LEUKOCYTES LEUKOCYTES (White blood (White blood cells)cells)

all fight infectionall fight infection BASOPHILSBASOPHILS

– MAST CELLMAST CELL EOSINOPHILSEOSINOPHILS NEUTROPHILSNEUTROPHILS MONOCYTESMONOCYTES

– MACROPHAGESMACROPHAGES LYMPHOCYTESLYMPHOCYTES

– B CELLSB CELLS– T CELLST CELLS

Basophils – only about Basophils – only about 0.5% of all leukocytes0.5% of all leukocytes– Granules secrete Granules secrete

histamineshistamines (vasodilation; (vasodilation; more WBCs can get to the more WBCs can get to the infection site)infection site)

– Antihistamines interfere Antihistamines interfere with the function of with the function of basophils.basophils.

– Mast Cell: a basophil that Mast Cell: a basophil that leaves the blood vessel leaves the blood vessel and enters the tissues. and enters the tissues.

BASOPHILSBASOPHILS

EosinophilsEosinophils

Eosinophils – Eosinophils – compose 1-4% of all compose 1-4% of all WBCsWBCs– Play roles in: Play roles in:

Ending Ending allergic allergic reactionsreactions, , parasitic parasitic infectionsinfections

During these During these conditions they conditions they increase in numbersincrease in numbers

Neutrophils – most Neutrophils – most numerous WBCnumerous WBC

First to respond to First to respond to infectioninfection– Phagocytize and destroy Phagocytize and destroy

bacteriabacteria– Also destroy bacterial Also destroy bacterial

toxins in body fluidstoxins in body fluids– Nucleus – has two to six Nucleus – has two to six

lobeslobes

NeutrophilsNeutrophils

MonocytesMonocytes Comprise about 5% of all Comprise about 5% of all

WBC’s.WBC’s. Like neutrophils, they Like neutrophils, they

phagocytize (eat) bacteria, old phagocytize (eat) bacteria, old cells, and foreign bodies.cells, and foreign bodies. They They have more types of lysosome have more types of lysosome enzymes than neutrophils so enzymes than neutrophils so they are better at killing they are better at killing difficult pathogens.difficult pathogens.

They also use antibodies for They also use antibodies for opsonization.opsonization.

When they leave the When they leave the bloodstream and enter the bloodstream and enter the tissues, they are calledtissues, they are called MACROPHAGES.MACROPHAGES.

20–45% of WBCs20–45% of WBCs– The most important cells of The most important cells of

the immune systemthe immune system– There are two types of There are two types of

lymphocytes; one type is lymphocytes; one type is effective in fighting infectious effective in fighting infectious organisms like body cells organisms like body cells infected with infected with virusesviruses

– Both types of lymphocytes act Both types of lymphocytes act against a against a specific foreign specific foreign molecule (antigen)molecule (antigen)

LymphocytesLymphocytes

Two main classes of lymphocyte Two main classes of lymphocyte – B cells – Originate in the bone marrow, B cells – Originate in the bone marrow,

mature into plasma cells. mature into plasma cells. A mature A mature plasma cell fights infection by plasma cell fights infection by producing antibodiesproducing antibodies

– T cells – Originate in the thymus gland. T cells – Originate in the thymus gland. They attack foreign cells directly They attack foreign cells directly ((including organ transplants!). including organ transplants!). They can also kill viruses.They can also kill viruses.

LymphocytesLymphocytes

B cells – mature into plasma cellsB cells – mature into plasma cells Plasma cells secrete antibodies; Plasma cells secrete antibodies;

the plasma cell’s antibodies are the plasma cell’s antibodies are what kills the attacking cell.what kills the attacking cell.

Antibodies attack in two ways:Antibodies attack in two ways:– They attach to bacteria and pop the cell They attach to bacteria and pop the cell

membranemembrane– They attach to encapsulated bacteria to They attach to encapsulated bacteria to

help neutrophils and macrophages to help neutrophils and macrophages to phagocytize them.phagocytize them.

LymphocytesLymphocytes

T cells are the cells that attack T cells are the cells that attack organ transplants!organ transplants!

Immunosuppression drugs are designed to Immunosuppression drugs are designed to inhibit the action of T cells. inhibit the action of T cells.

T cells are attacked by the HIV (AIDS) T cells are attacked by the HIV (AIDS) virus.virus.

The thymus gland secrets certain The thymus gland secrets certain hormones which can cause T cells to hormones which can cause T cells to become immunocompetent (makes become immunocompetent (makes the cells mature and start to work)the cells mature and start to work)

T-cell LymphocytesT-cell Lymphocytes

T CellsT CellsThere are several types of T cells. The main types areThere are several types of T cells. The main types are Cytotoxic (Killer) T cellsCytotoxic (Killer) T cells

– Go out and directly kill bacteria or infected host Go out and directly kill bacteria or infected host cells cells

Helper T cellsHelper T cells– Release chemicals called “cytokines” to call in Release chemicals called “cytokines” to call in

more white blood cells of all types to join in the more white blood cells of all types to join in the war. They also present the macrophage’s antigen war. They also present the macrophage’s antigen to a plasma cell, which causes the plasma cell to to a plasma cell, which causes the plasma cell to produce antibodies against that particular bacteria. produce antibodies against that particular bacteria.

Suppressor T cellsSuppressor T cells– Stop the immune process when it is over, and also "tell" Stop the immune process when it is over, and also "tell"

some plasma cells to "remember" how to destroy that some plasma cells to "remember" how to destroy that specific pathogen. Those plasma B-cells are then called specific pathogen. Those plasma B-cells are then called Memory B-Cells. They can react to the same pathogen faster, Memory B-Cells. They can react to the same pathogen faster, the next time it invades because Memory B-cells already the next time it invades because Memory B-cells already have the proper antibodies stored up for that pathogen.have the proper antibodies stored up for that pathogen.

Neutrophil

Macrophage(Monocyte in

bloodstream)

B-CellKiller

T-CellHelper T-Cell

Suppressor T-Cell

Plasma Cell

Lymphocytes

Phagocytosis

Bacteria

Virus

Presentation

Y Y

YAntibodies

Y

Y

Pops the cell

Capsule

Cytokines

Pops the cell

STOP

Opsonization

Bacteria

Presentation

PlateletsPlatelets Cell fragmentsCell fragments

– Break off from Break off from megakaryocytesmegakaryocytes

Function in clotting Function in clotting of bloodof blood

Megakaryocyte

Platelets

RBC DevelopmentRBC Development

A mature RBC is called an A mature RBC is called an ERYTHROCYTE,ERYTHROCYTE, which circulates in which circulates in the blood. the blood.

If the body makes too few If the body makes too few erythrocytes it can lead to one form erythrocytes it can lead to one form of of ANEMIA.ANEMIA.

ERYTHROBLASTSERYTHROBLASTS

These mature into These mature into RETICULOCYTESRETICULOCYTES, , a RBC with bits of a RBC with bits of nucleus material, nucleus material, which later which later dissolves to make dissolves to make room for more room for more Hgb. It is now Hgb. It is now called an called an EERYTHROCYTERYTHROCYTE. .

AnemiaAnemia

Characteristic sign of anemia: see Characteristic sign of anemia: see reticulocytes in the blood reticulocytes in the blood (immature red blood cells). (immature red blood cells).

Remnants of the nucleus are still in Remnants of the nucleus are still in the cell.the cell.

Disorders of RBCsDisorders of RBCs

Polycythemia Polycythemia AnemiaAnemia

– Too few RBC’sToo few RBC’s– Iron deficiencyIron deficiency– Hemorrhagic anemia (person lost blood)Hemorrhagic anemia (person lost blood)– Pernicious anemia (lack of vitamin B12 or intrinsic Pernicious anemia (lack of vitamin B12 or intrinsic

factor)factor)– Excess RBC destruction (immune disorder or Excess RBC destruction (immune disorder or

infection)infection)– Hemoglobin abnormalitiesHemoglobin abnormalities

ThalassemiaThalassemia Sickle cell disease Sickle cell disease Megaloblastic anemia (pernicious anemia)Megaloblastic anemia (pernicious anemia)

More Causes of Anemia

Hemorrhagic anemia: loss of blood Pernicious anemia: lack of vitamin B12

or intrinsic factor, which is needed to make the hemoglobin in a RBC

Excess RBC destruction (from an autoimmune disease, infection, etc)

Genetic defect in Hemoglobin (deforms the cell)

TEAR DROP

SPHEROCYTE

TARGET CELLS

ThalassemiaThalassemia A form of anemia where the RBCs have abnormal A form of anemia where the RBCs have abnormal

hemoglobin that deforms the cellshemoglobin that deforms the cells

Sickle Cell DiseaseSickle Cell Disease

Present in Present in African AmericansAfrican Americans more more than in other groups, and is always than in other groups, and is always characterized by sickled characterized by sickled erythrocytes.erythrocytes.

Megaloblastic AnemiaMegaloblastic Anemia(Large RBCs: Note that the lymphocyte is the same size as the huge RBCs)

HematocritHematocrit A quick screening test for anemia is the A quick screening test for anemia is the

hematocrit.hematocrit. A drop of blood is drawn up a small glass capillary A drop of blood is drawn up a small glass capillary

tube and the tube is centrifuged to pack the red tube and the tube is centrifuged to pack the red blood cells at the bottom with the plasma on top. blood cells at the bottom with the plasma on top.

Hematocrit measures the percentage of blood Hematocrit measures the percentage of blood volume that consists of erythrocytes.volume that consists of erythrocytes.

The hematocrit is the ratio of packed red blood The hematocrit is the ratio of packed red blood cells to total blood volume.cells to total blood volume.

Normal is about 45% (46% for men and 38% for Normal is about 45% (46% for men and 38% for women.)women.)

Disorders of WBCsDisorders of WBCs Disorders of leukocytesDisorders of leukocytes

– Leukemia – too few mature WBC’s (may Leukemia – too few mature WBC’s (may see increase in immature forms); a form see increase in immature forms); a form of cancerof cancer

– Classified as Classified as lymphoblastic lymphoblastic (too many (too many immature lymphocytes) or immature lymphocytes) or myeloblasticmyeloblastic (too many immature (too many immature neutrophils)neutrophils)

Disorders of PlateletsDisorders of Platelets

– Thrombocytopenia Thrombocytopenia Abnormally low Abnormally low

concentration of concentration of plateletsplatelets

Blood does not clot Blood does not clot properly properly

HEMOPHILIAHEMOPHILIA

A hereditary disease of males, where they A hereditary disease of males, where they are unable to clot properly because they are unable to clot properly because they are missing some clotting factors.are missing some clotting factors.

When they get even a slight bump or When they get even a slight bump or bruise they have to have an intravenous bruise they have to have an intravenous infusion of clotting factors or they will infusion of clotting factors or they will bleed to death. bleed to death.

This is probably the disease that was in This is probably the disease that was in the genes of Henry VIII, which caused all of the genes of Henry VIII, which caused all of his male children to become weak and die his male children to become weak and die in infancy.in infancy.

Blood ClotsBlood Clots

ThrombusThrombus– A clot in a vessel A clot in a vessel

EmbolismEmbolism– a thrombus that broke away a thrombus that broke away

and travels in the blood and travels in the blood stream. stream.

– It usually lodges in a smaller It usually lodges in a smaller blood vessel and blocks blood vessel and blocks circulation distal to that point.circulation distal to that point.

BLOOD TYPINGBLOOD TYPING

These proteins are called antigens (something These proteins are called antigens (something that causes an allergic reaction). There are two that causes an allergic reaction). There are two types of blood antigens: Type A and Type B.types of blood antigens: Type A and Type B.

A person with Type A antigens on their blood A person with Type A antigens on their blood cells have Type A blood.cells have Type A blood.

A person with Type B antigens have Type B A person with Type B antigens have Type B blood.blood.

A person with both types has type AB blood.A person with both types has type AB blood. A person with neither antigen has type O blood.A person with neither antigen has type O blood.

RH FACTORRH FACTOR

The reason this is so important is that if The reason this is so important is that if an Rh- mother has an Rh+ fetus in her an Rh- mother has an Rh+ fetus in her womb (from an Rh+ father), her womb (from an Rh+ father), her antibodies will attack the red blood antibodies will attack the red blood cells of the fetus because her body cells of the fetus because her body detects the Rh protein on the baby’s detects the Rh protein on the baby’s red blood cells and thinks they are red blood cells and thinks they are foreign objects. This is called Hemolytic foreign objects. This is called Hemolytic Disease of the Newborn (HDN).Disease of the Newborn (HDN).

IMMUNE SYSTEMIMMUNE SYSTEM

INFLAMMATORY REACTION: INFLAMMATORY REACTION: When you When you get stuck by a thorn or have an infected get stuck by a thorn or have an infected cut, the body goes through a series of cut, the body goes through a series of events called an inflammatory reaction. events called an inflammatory reaction.

Four outward signs:Four outward signs:– Redness (erythema or rubor)Redness (erythema or rubor)– Heat (calor)Heat (calor)– Swelling (edema)Swelling (edema)– Pain (dolor)Pain (dolor)

ADAPTIVE IMMUNITYADAPTIVE IMMUNITY

Two types of Adaptive Two types of Adaptive ImmunityImmunity– ACTIVE immunityACTIVE immunity

Naturally AcquiredNaturally Acquired Artificially AcquiredArtificially Acquired

– PASSIVE PASSIVE immunityimmunity Naturally Naturally

AcquiredAcquired Artificially Artificially

AcquiredAcquiredYou can also think of it this way

ALLERGIESALLERGIES

From a hypersensitivity to From a hypersensitivity to substances such as pollen or animal substances such as pollen or animal hair that would not ordinarily cause a hair that would not ordinarily cause a reaction. There are two types of reaction. There are two types of allergic responses:allergic responses:

Immediate Immediate DelayedDelayed

AUTOIMMUNE DISEASEAUTOIMMUNE DISEASE

A hereditary problem where the body A hereditary problem where the body thinks its own tissues are foreign thinks its own tissues are foreign bodies, and it constantly tries to kill bodies, and it constantly tries to kill off its own tissues.off its own tissues.

Tunica intima Endothelium SubendotheliumTunica media Smooth muscles Elastic fibersTunica adventitia

Vasa vasorum

Types of Blood VesselsTypes of Blood Vessels

Arteries – carry blood away from the heartArteries – carry blood away from the heart– It does not matter if it is oxygenated or deoxy It does not matter if it is oxygenated or deoxy

blood. If it is leaving the heart, it is an artery.blood. If it is leaving the heart, it is an artery. Capillaries – smallest blood vesselsCapillaries – smallest blood vessels

– The site of exchange of molecules between The site of exchange of molecules between blood and tissue fluidblood and tissue fluid

Veins – carry blood toward the heartVeins – carry blood toward the heartIt does not matter if it is oxygenated or deoxy blood. It does not matter if it is oxygenated or deoxy blood. If it is entering the heart, it is a vein.If it is entering the heart, it is a vein.

ArteriesArteries ARTERIES ARTERIES carry carry

blood away from the blood away from the heart.heart.

Arteries have a Arteries have a smaller lumen than smaller lumen than veins of similar size. veins of similar size.

Arterial walls are Arterial walls are thicker than venous thicker than venous walls.walls.

Arteries have more Arteries have more elastin than veins.elastin than veins.

Arteries have no Arteries have no valves because the valves because the blood pressure in blood pressure in arteries is high arteries is high enough that there is enough that there is no backflow of no backflow of blood.blood.

ARTERIOLESARTERIOLES

These are microscopic; they are the These are microscopic; they are the smallest type of artery. smallest type of artery.

Large ones look like muscular arteries.Large ones look like muscular arteries. Small ones only have two layers: Small ones only have two layers:

endothelium and tunica media. endothelium and tunica media. One of the characteristics of an One of the characteristics of an

arteriole is that when it contracts, the arteriole is that when it contracts, the lumen closes completely.lumen closes completely.

AneurysmAneurysm A sac-like outpouching of A sac-like outpouching of an arteryan artery– Can rupture at any Can rupture at any

time; in aorta or brain time; in aorta or brain can cause death can cause death within a few seconds. within a few seconds.

– Symptoms: Swelling or Symptoms: Swelling or throbbing throbbing (asymptomatic in (asymptomatic in brain)brain)

Some common locations Some common locations for aneurysms include:for aneurysms include:– AortaAorta– Brain Brain – Leg Leg – Intestine Intestine

(mesenteric artery (mesenteric artery aneurysm) aneurysm)

– Splenic artery Splenic artery aneurysm (can form aneurysm (can form during pregnancy) during pregnancy)

AneurysmAneurysm

Causes of an aneurysm:Causes of an aneurysm:– Defect in part of the artery wallDefect in part of the artery wall– High blood pressure (abdominal aortic High blood pressure (abdominal aortic

aneurysms)aneurysms)– Congenital (present at birth)Congenital (present at birth)

Usually not detected except by an Usually not detected except by an angiogram or ultrasound.angiogram or ultrasound.

Treatment: surgical repairTreatment: surgical repair

Some clinically significant Some clinically significant arteriesarteries

Femoral artery: easy to find pulse, Femoral artery: easy to find pulse, but susceptible to injury.but susceptible to injury.

Circle of Willis: loop of arteries Circle of Willis: loop of arteries around pituitary and optic chiasma. around pituitary and optic chiasma. Common area for stroke to cause Common area for stroke to cause blindness.blindness.

Types of CapillariesTypes of Capillaries

CONTINUOUS CAPILLARIESCONTINUOUS CAPILLARIES FENESTRATED CAPILLARIESFENESTRATED CAPILLARIES DISCONTINUOUS CAPILLARIESDISCONTINUOUS CAPILLARIES

PRE-CAPILLARY PRE-CAPILLARY SPHINCTERSPHINCTER

A small muscle in front of each capillary, A small muscle in front of each capillary, controls the flow of blood to individual controls the flow of blood to individual capillaries.capillaries.

ARTERIOLESARTERIOLES direct the blood flow to the direct the blood flow to the specific specific tissuetissue. PRE-CAPILLARY SPHINCTERS . PRE-CAPILLARY SPHINCTERS direct the blood flow to specific direct the blood flow to specific cellscells. .

If one cell is starving, the capillary next to it If one cell is starving, the capillary next to it will open. The sphincter opens and closes will open. The sphincter opens and closes depending on the needs of individual cells.depending on the needs of individual cells.

VeinsVeins

Veins take blood TO the heart. Two Veins take blood TO the heart. Two types:types:– Venuole: from the capillary to the veinVenuole: from the capillary to the vein– Vein: takes blood to the heart.Vein: takes blood to the heart.

Thinner walls (less pressure here)Thinner walls (less pressure here) Larger lumen (blood moves more slowly)Larger lumen (blood moves more slowly) Skeletal muscle pushes on the vein to move Skeletal muscle pushes on the vein to move

the blood uphill. the blood uphill. Need valves in veins Need valves in veins

Valves in VeinsValves in Veins

How does blood get uphill back to the How does blood get uphill back to the heart? Veins need valves. heart? Veins need valves.

Veins are the only BLOOD vessels that Veins are the only BLOOD vessels that have valves (although LYMPH vessels also have valves (although LYMPH vessels also have valves). have valves).

Valves in veins allow blood to move in only Valves in veins allow blood to move in only one direction. What pushes the blood? one direction. What pushes the blood? The muscles of the body constrict, The muscles of the body constrict, squeezing the vessels. This is a type of squeezing the vessels. This is a type of blood pump.blood pump.

Clinically Significant VeinsClinically Significant Veins

Greater Saphenous veinGreater Saphenous vein: used for : used for coronary bypass; most likely becomes coronary bypass; most likely becomes varicose. varicose.

Facial veinFacial vein: “Danger triangle” : “Danger triangle” infection spreads to meninges in infection spreads to meninges in brain.brain.

Renal vein: oxygen poor, and Renal vein: oxygen poor, and contains the lowest concentration contains the lowest concentration of nitrogen waste.of nitrogen waste.

Veins that are rich in Veins that are rich in oxygen and nutrientsoxygen and nutrients

Umbilical vein Umbilical vein Hepatic Portal veinHepatic Portal vein Pulmonary veinPulmonary vein

Varicose VeinsVaricose Veins

The valves become incompetent:The valves become incompetent: They can’t close all the way because They can’t close all the way because

too much fluid has built up in them too much fluid has built up in them and the lumen has stretched too and the lumen has stretched too wide. wide.

They might be asymptomatic or they They might be asymptomatic or they may be painful (phlebitis).may be painful (phlebitis).

EdemaEdema If the veins are varicose for a long time, If the veins are varicose for a long time,

plasma may leak out into the tissues, plasma may leak out into the tissues, causing edema. causing edema.

Edema means swelling anywhere in the Edema means swelling anywhere in the body (including from an injury or from body (including from an injury or from hanging your legs down too long like hanging your legs down too long like when on an airplane), but it frequently when on an airplane), but it frequently occurs from incompetent veins in the legs. occurs from incompetent veins in the legs. There are two types of edema:There are two types of edema:– PittingPitting– Non-pittingNon-pitting

PHLEBITISPHLEBITIS

Inflammation of a veinInflammation of a vein Usually in the legs.Usually in the legs. When phlebitis is associated with the When phlebitis is associated with the

formation of blood clots (thrombosis), formation of blood clots (thrombosis), usually in the deep veins of the legs, usually in the deep veins of the legs, the condition is called Deep Vein the condition is called Deep Vein Thrombophlebitis (DVT)Thrombophlebitis (DVT)..

DEEP VEIN DEEP VEIN THROMBOPHLEBITISTHROMBOPHLEBITIS

Signs and SymptomsSigns and Symptoms Redness (erythema) and warmth Redness (erythema) and warmth

with a temperature elevation of a with a temperature elevation of a degree or more above the baseline degree or more above the baseline

Pain or burning along the length of Pain or burning along the length of the vein the vein

Swelling (edema) Swelling (edema) Vein being hard, and cordlike Vein being hard, and cordlike Need ER if all symptoms are presentNeed ER if all symptoms are present

Spider VeinsSpider Veins Small superficial veins become varicose Small superficial veins become varicose

and do not function properly.and do not function properly. Cause an unsightly appearance but are Cause an unsightly appearance but are

not dangerous.not dangerous. Injections of alcohol or saline into the Injections of alcohol or saline into the

vein will sclerose them (scar them shut).vein will sclerose them (scar them shut). A laser can also be used to do the same.A laser can also be used to do the same. After treatment, macrophages will After treatment, macrophages will

eventually phagocytize them and they eventually phagocytize them and they will disappear.will disappear.

Tissue NecrosisTissue Necrosis

Necrosis = deadNecrosis = dead Caused by infection, toxins, or Caused by infection, toxins, or

traumatrauma Almost always detrimental and can Almost always detrimental and can

be fatalbe fatal

Peripheral Vascular Disease Peripheral Vascular Disease (PVD)(PVD)

Refers to the obstruction of large arteries, frequently Refers to the obstruction of large arteries, frequently in the lower extremity. Usually caused from in the lower extremity. Usually caused from atherosclerosis (fatty plaques).atherosclerosis (fatty plaques).

SymptomsSymptoms– Claudication: pain, weakness, numbness, or Claudication: pain, weakness, numbness, or

cramping in muscles due to decreased blood flowcramping in muscles due to decreased blood flow– Sores, wounds, or ulcers that heal slowly or not at Sores, wounds, or ulcers that heal slowly or not at

allall– Change in color (blueness or paleness) or Change in color (blueness or paleness) or

temperature (coolness) when compared to the temperature (coolness) when compared to the other limbother limb

– Diminished hair and nail growth on affected limb Diminished hair and nail growth on affected limb and digits (shiny, hairless skin)and digits (shiny, hairless skin)

Lymph SystemLymph System The lymph system retrieves excess tissue The lymph system retrieves excess tissue

fluid (plasma that leaks out of the blood fluid (plasma that leaks out of the blood vessels) and filters it and cleans it and vessels) and filters it and cleans it and returns it to the blood.returns it to the blood.

This plasma is now called lymphatic fluid. It is This plasma is now called lymphatic fluid. It is sent through the lymph nodes throughout the sent through the lymph nodes throughout the body. body.

There are hundreds of lymph nodes in the body, There are hundreds of lymph nodes in the body, occurring in clusters. occurring in clusters.

Each lymph node filters the lymph fluid to get rid Each lymph node filters the lymph fluid to get rid of bacteria and viruses, and returns the fluid back of bacteria and viruses, and returns the fluid back into the blood.into the blood.

How does lymph move?How does lymph move?

All of the following mechanisms help All of the following mechanisms help move lymph through the lymphatic move lymph through the lymphatic vesselsvessels

Body movements during exerciseBody movements during exercise Contraction of skeletal musclesContraction of skeletal muscles Contractions of smooth muscle in the Contractions of smooth muscle in the

wall of the lymph vessels.wall of the lymph vessels.

Network of lymph vesselsNetwork of lymph vessels

Lymph vessels drain into the right Lymph vessels drain into the right thoracic duct near the clavicle. thoracic duct near the clavicle.

Lymph NodeLymph Node

Figure 20.4a

GIANT LYMPH NODESGIANT LYMPH NODES

Considered as lymph organsConsidered as lymph organs 1. TONSILS and ADENOIDS1. TONSILS and ADENOIDS 2. THYMUS2. THYMUS 3. PAYER’S PATCHES3. PAYER’S PATCHES 4. APPENDIX4. APPENDIX 5. SPLEEN5. SPLEEN

Lymph DisordersLymph Disorders Hodgkin’s Disease:Hodgkin’s Disease: cancer of lymph node; cancer of lymph node;

does NOT feel tender does NOT feel tender LymphangitisLymphangitis: inflammation of lymph vessels, : inflammation of lymph vessels,

usually from infection usually from infection Mononucleosis:Mononucleosis: Epstein-Barr virus attacks B- Epstein-Barr virus attacks B-

lymphocytes; characterized by inflammation of lymphocytes; characterized by inflammation of lymph vessels (lymphangitis).lymph vessels (lymphangitis).

Edema:Edema: accumulation of fluid in connective accumulation of fluid in connective tissuetissue

Bubo:Bubo: infected node with trapped pathogens that infected node with trapped pathogens that are not destroyed are not destroyed

Layers of tissues around the heart:Layers of tissues around the heart:

Parietal pericardium

Visceralpericardium

PERICARDIUM1) Parietal pericardium2) Pericardial cavity3) Visceral pericardium

HEART1) Epicardium (same as visceral pericardium)2) Myocardium3) Endocardium

PERICARDITISPERICARDITIS

Inflamed outer layer of heart. Inflamed outer layer of heart. Fluid accumulates in pericardial cavity, Fluid accumulates in pericardial cavity,

putting pressure on heart putting pressure on heart improper beat improper beat Pericarditis can be caused by damage to Pericarditis can be caused by damage to

the blood vessels the blood vessels blood leaks into blood leaks into pericardial cavity pericardial cavity pressure pressure improper improper beat. beat.

Pericarditis can lead to pericardial friction Pericarditis can lead to pericardial friction rub, adhesions, and additional excess fluid rub, adhesions, and additional excess fluid in the pericardial cavity.in the pericardial cavity.

PERICARDITISPERICARDITIS CARDIAC TAPENADECARDIAC TAPENADE: In severe cases of : In severe cases of

pericarditis, or if there is a stab wound to the pericarditis, or if there is a stab wound to the heart wall that causes fluid to exude into the heart wall that causes fluid to exude into the pericardial cavity. pericardial cavity.

The excess fluid compresses the heart and The excess fluid compresses the heart and diminishes the heart’s ability to pump.diminishes the heart’s ability to pump.

Don’t get this confused with arrhythmia that is Don’t get this confused with arrhythmia that is caused from a problem with the SA or AV node. caused from a problem with the SA or AV node. The irregular heart beat from cardiac tapenade The irregular heart beat from cardiac tapenade is caused from fluid entering the pericardial is caused from fluid entering the pericardial cavity and putting pressure on the heart. cavity and putting pressure on the heart.

Treatment is to stick a needle in the cavity and Treatment is to stick a needle in the cavity and drain the fluid.drain the fluid.

ENDOCARDITISENDOCARDITIS More serious: More serious: Bacteria enter bloodstream (dental Bacteria enter bloodstream (dental

procedures, IV drug abuse, catheter) procedures, IV drug abuse, catheter) damage to lining and valves damage to lining and valves blood clots.blood clots.

Those who already have damaged Those who already have damaged heart valves need prophylactic heart valves need prophylactic antibiotics.antibiotics.

Don’t get endocarditis (bacterial Don’t get endocarditis (bacterial infection) mixed up with pericarditis, infection) mixed up with pericarditis, which can lead to cardiac tapenade.which can lead to cardiac tapenade.

Blood FlowBlood Flow

When the ventricles relax, the When the ventricles relax, the PULMONARY SEMILUNAR VALVE PULMONARY SEMILUNAR VALVE closes to prevent blood from going closes to prevent blood from going from the pulmonary artery back into from the pulmonary artery back into the right ventricle.the right ventricle.

Do the semilunar valves have a chordae Do the semilunar valves have a chordae tendonae? tendonae?

No; the blood is not being forced back No; the blood is not being forced back (with a contraction), it just falls back with (with a contraction), it just falls back with gravity, so there’s not as much pressure.gravity, so there’s not as much pressure.

• Therefore, the left ventricle is the chamber which is responsible for generating the largest pressure upon contraction.

LA

LV

IVC

Pulmonary artery

Aorta

Pulmonary vein

SVC

RA

RV

Tricuspid valve

Bicuspid valve (Mitral)

Pulmonary semilunar valve

• The blood then goes past the AORTIC SEMILUNAR VALVE, into the AORTA, and back to the body.

LA

LV

IVC

Pulmonary artery

Aorta

Pulmonary vein

SVC

RA

RV

Tricuspid valve

Bicuspid valve (Mitral)

Aortic semilunar valve

Pulmonary semilunar valve

Body

The semilunar valves are located between the ventricles and the great arteries.

SUMMARY OF BLOOD SUMMARY OF BLOOD FLOWFLOW

Deoxy blood Deoxy blood sup/inf vena cava sup/inf vena cava R atrium R atrium tricuspid valve tricuspid valve R R ventricle ventricle pulmonary semilunar pulmonary semilunar valve valve pulmonary artery pulmonary artery lungs lungs pulmonary veins pulmonary veins Left atrium Left atrium mitral (bicuspid) valve mitral (bicuspid) valve Left Left ventricle ventricle aortic semilunar valve aortic semilunar valve aorta aorta rest of body. rest of body.

Mitral Valve Stenosis • If there is stenosis (blockage) of the mitral valve, where will

the blood back up into?

• Answer: the pulmonary circulation.

LA

LV

IVC

Pulmonary artery

Aorta

Pulmonary vein

SVC

RA

RV

Tricuspid valve

Bicuspid valve (Mitral)

Aortic semilunar valve

Pulmonary semilunar valve

Body

Lungs

HEART BEATSHEART BEATS The pressure of blood against blood vessel The pressure of blood against blood vessel

walls is called blood pressure.walls is called blood pressure. Blood pressure is recorded systole over Blood pressure is recorded systole over

diastole. Normal resting blood pressure is diastole. Normal resting blood pressure is said to be 120/80. When blood pressure is said to be 120/80. When blood pressure is too high, it is called too high, it is called HYPERTENSION.HYPERTENSION.

The sound your heart makes when it is The sound your heart makes when it is beating is the sound of the blood hitting the beating is the sound of the blood hitting the valves after they are closed.valves after they are closed.

The heart normally beats at a rate of 60-80 The heart normally beats at a rate of 60-80 beats per minute. A faster (beats per minute. A faster (tachycardiatachycardia) or ) or slower (slower (bradycardiabradycardia) heart rate is an ) heart rate is an indication of a problem.indication of a problem.

HEART BEATSHEART BEATS

SYSTOLE: SYSTOLE: – Ventricles contract Ventricles contract – Atria relaxAtria relax

DIASTOLE:DIASTOLE:– Ventricles relaxVentricles relax– Atria contractAtria contract

Valve ProblemsValve Problems

HEART MURMURHEART MURMUR – If the valve leaks, it doesn’t close If the valve leaks, it doesn’t close

all the wayall the way– ““Lub-squirt”Lub-squirt”– Most murmurs are benign; fairly Most murmurs are benign; fairly

common, esp. in babies and some common, esp. in babies and some adults.adults.

Valve ProblemsValve Problems PROLAPSED VALVEPROLAPSED VALVE is more serious. is more serious. Mitral valve is most likely to prolapse because it Mitral valve is most likely to prolapse because it

pumped the hardest. See how much thicker the pumped the hardest. See how much thicker the left ventricle is? Mitral Valve Prolapse is the most left ventricle is? Mitral Valve Prolapse is the most common heart valve disorder. Might need common heart valve disorder. Might need artificial valve.artificial valve.

What controls the heart What controls the heart beat?beat? There is a small region in the right There is a small region in the right

atrium = SA NODE (Sino-atrium node) atrium = SA NODE (Sino-atrium node) = pacemaker of the heart. Its job is = pacemaker of the heart. Its job is to speed up or slow down the heart to speed up or slow down the heart rate as needed. rate as needed.

SA node sends an electrical signal SA node sends an electrical signal (action potential) to the AV NODE (action potential) to the AV NODE (atrio-ventricular node) (atrio-ventricular node) atrium atrium contraction contraction then the signal pauses then the signal pauses while the signal is transmitted to both while the signal is transmitted to both ventricles (atria are now relaxing) ventricles (atria are now relaxing) sends the action potential to all parts sends the action potential to all parts of the heart so it can contract.of the heart so it can contract.

Conducting SystemConducting System

Heart BeatsHeart Beats

The heart does not need a nerve to stimulate it to The heart does not need a nerve to stimulate it to contract; rather, specialized heart cells can contract; rather, specialized heart cells can spontaneously start an action potential that spontaneously start an action potential that spreads to depolarize the rest of the cardiac spreads to depolarize the rest of the cardiac muscle cells. These are the specialized cells:muscle cells. These are the specialized cells:– A. SA nodeA. SA node– B. AV nodeB. AV node– C. Bundle of His (AV bundle)C. Bundle of His (AV bundle)– D. left and right bundle branchesD. left and right bundle branches– E. Purkinje fibersE. Purkinje fibers

Heart BeatsHeart Beats This is the orderThis is the order in which these specialized cells function: in which these specialized cells function:

First the Sinoatrial First the Sinoatrial (SA) node(SA) node starts an action potential which causes starts an action potential which causes the atria to depolarize. the atria to depolarize.

This depolarization will then reach the This depolarization will then reach the AV nodeAV node at the bottom portion of at the bottom portion of the right atrium and there is a delay here because these cells are so the right atrium and there is a delay here because these cells are so small in diameter. small in diameter.

Another delay in the transmission of the depolarization at the Another delay in the transmission of the depolarization at the bundle of bundle of His (AV bundle)His (AV bundle) because these special heart cells travel through the because these special heart cells travel through the atrioventricular septum which is non-conductive fibrous connective atrioventricular septum which is non-conductive fibrous connective tissue.tissue.

The Bundle of His slows down the electrical pathway to give the atria a The Bundle of His slows down the electrical pathway to give the atria a chance to finish contacting.chance to finish contacting.

Next, the depolarizing event travels through the Next, the depolarizing event travels through the left and right bundle left and right bundle branches,branches, found in the interventricular septum, to finally arrive at the found in the interventricular septum, to finally arrive at the Purkinje fibersPurkinje fibers in the lateral walls of the myocardium of the ventricles. in the lateral walls of the myocardium of the ventricles.

ProblemsProblems

ARRHYTHMIAARRHYTHMIA Problem with the SA or AV node Problem with the SA or AV node

improper heart beat. improper heart beat. Treatment is medicines or a Treatment is medicines or a

pacemaker.pacemaker.

Ventricular FibrillationVentricular Fibrillation FIBRILLATIONFIBRILLATION is when the heart is when the heart

beat is not really present…it just beat is not really present…it just vibrates. vibrates.

A heart in fibrillation does not A heart in fibrillation does not contract rhythmically; it just quivers contract rhythmically; it just quivers without pumping blood.without pumping blood.

The ventricles are unable to pump The ventricles are unable to pump blood efficiently due to rapid, random blood efficiently due to rapid, random contraction of cardiac muscle fibers.contraction of cardiac muscle fibers.

The muscle doesn’t contract as a unit. The muscle doesn’t contract as a unit. Treatment is defibrillate with electric Treatment is defibrillate with electric shock shock closes down heart closes down heart maybe maybe it will restart. it will restart.

Coronary VesselsCoronary Vessels

1)1) Right coronary arteryRight coronary arteryThe left one is too short to be countedThe left one is too short to be counted

2) Circumflex artery2) Circumflex artery

3) Anterior Interventricular artery3) Anterior Interventricular artery

4) Posterior Interventricular artery4) Posterior Interventricular artery

The The coronary sinus coronary sinus is a collection of veins joined is a collection of veins joined together to form a large vessel that collects blood together to form a large vessel that collects blood from the myocardium of the heart and delivers it from the myocardium of the heart and delivers it into the right atrium.into the right atrium.

THE HEART NEEDS ITS THE HEART NEEDS ITS OWN BLOOD/O2OWN BLOOD/O2

If one of the four coronary arteries If one of the four coronary arteries becomes clogged, becomes clogged, ISCHEMIAISCHEMIA (lack of (lack of oxygen) to part of the heart muscle will oxygen) to part of the heart muscle will result. result.

This is a painful condition, and the pain of This is a painful condition, and the pain of it is called it is called ANGINAANGINA (heart pain). (heart pain).

If nothing is done immediately to increase If nothing is done immediately to increase the blood flow, the myocardial tissue can the blood flow, the myocardial tissue can die; this condition is called a die; this condition is called a HEART HEART ATTACK.ATTACK.

Coronary BypassCoronary Bypass

People who have an angina attack People who have an angina attack can take nitroglycerine as a tablet can take nitroglycerine as a tablet under the tongue that dissolves under the tongue that dissolves quickly. quickly.

This medicine will dilate the blood This medicine will dilate the blood vessels. vessels.

Coronary BypassCoronary Bypass

When a person has their first When a person has their first angina attack, the doctor will angina attack, the doctor will order an order an ANGIOGRAMANGIOGRAM to look to look for a narrowing in an artery, for a narrowing in an artery, especially in one of the coronary especially in one of the coronary arteries. arteries.

Coronary BypassCoronary Bypass

If a coronary artery is found to have If a coronary artery is found to have a severe blockage, they can do a a severe blockage, they can do a CORONARY BYPASSCORONARY BYPASS. .

In this procedure, the doctor takes In this procedure, the doctor takes another blood vessel graft (from the another blood vessel graft (from the greater saphenous vein in the thigh) greater saphenous vein in the thigh) and sews it in around the blockage.and sews it in around the blockage.

For double or triple bypasses, that’s For double or triple bypasses, that’s how many vessels are affected. how many vessels are affected.

TERMSTERMS

ANGINA: ANGINA: heart pain, usually caused heart pain, usually caused from not enough oxygen to the from not enough oxygen to the myocardium (ischemia)myocardium (ischemia)

ISCHEMIA: ISCHEMIA: lack of blood/oxygenlack of blood/oxygen MYOCARDIAL INFARCTION: MYOCARDIAL INFARCTION: heart heart

attack from blood clot in coronary attack from blood clot in coronary artery, causing ischemia, which artery, causing ischemia, which causes anginacauses angina

HEART ATTACKHEART ATTACK

Not enough blood to the heart’s Not enough blood to the heart’s myocardium layer myocardium layer MILD ISCHEMIAMILD ISCHEMIA severe pain: severe pain: ANGINA (angina pectoris)ANGINA (angina pectoris)– Treatment is nitroglycerine to open arteriesTreatment is nitroglycerine to open arteries

Complete blockage Complete blockage not enough O2 to not enough O2 to that area = that area = SEVERE ISCHEMIA SEVERE ISCHEMIA that that part of heart muscle diespart of heart muscle dies = = MYOCARDIAL MYOCARDIAL INFARCTIONINFARCTION. .

Heart muscle never regenerates. If a large Heart muscle never regenerates. If a large area dies, person will die.area dies, person will die.

Heart MedicinesHeart Medicines

t-PA (dissolves blood clots)t-PA (dissolves blood clots) Beta-blockers (slows heart rate)Beta-blockers (slows heart rate) Aspirin (prevents blood clots)Aspirin (prevents blood clots) Nitroglycerine (dilates coronary Nitroglycerine (dilates coronary

arteries) arteries)

Causes of High Blood Causes of High Blood PressurePressure

ARTERIOSCLEROSIS ARTERIOSCLEROSIS (hardening of the arteries): (hardening of the arteries): caused by a build-up of calcium deposits in the caused by a build-up of calcium deposits in the artery wall; artery cannot expand with blood artery wall; artery cannot expand with blood surges. Tends to be hereditary. surges. Tends to be hereditary.

The blood vessel becomes hard like a rock; The blood vessel becomes hard like a rock; it can’t expand or contract, causes it can’t expand or contract, causes increase in blood pressure. increase in blood pressure.

Diet and exercise don’t help this much. Diet and exercise don’t help this much. Both arteriosclerosis and atherosclerosis Both arteriosclerosis and atherosclerosis cause high blood pressure. cause high blood pressure.

Causes of High Blood Causes of High Blood PressurePressure

ATHEROSCLEROSISATHEROSCLEROSIS (a build-up of (a build-up of fat in the arteries): caused from fat in the arteries): caused from eating eating fatty food fatty food narrowing of narrowing of artery artery Spasm shut or blood clot. Spasm shut or blood clot.

EMBOLISMEMBOLISM

When fat builds up in a lump in one When fat builds up in a lump in one place, it is called aplace, it is called a PLAQUE. PLAQUE. It It causes the lumen to narrow, causes the lumen to narrow, restricting blood flow. restricting blood flow.

If this If this fatty fatty plaque breaks off and plaque breaks off and travels in the bloodstream, it is now travels in the bloodstream, it is now called an called an EMBOLISMEMBOLISM. An embolism . An embolism can also be made of can also be made of bloodblood instead of instead of fat.fat.

How a thrombus becomes How a thrombus becomes embolismembolism

If a platelet catches on a piece of this fat, If a platelet catches on a piece of this fat, it can start a it can start a bloodblood clot (thrombus). clot (thrombus).

If a piece of the clot If a piece of the clot (thrombus)(thrombus) breaks breaks off and enters the circulation, it is off and enters the circulation, it is now called an embolismnow called an embolism, it can lodge in , it can lodge in a smaller blood vessel and block the a smaller blood vessel and block the oxygen to all the tissue past that point, oxygen to all the tissue past that point, and the tissue dies.and the tissue dies.

Blockage of blood vesselBlockage of blood vessel

If the embolism lodges in the If the embolism lodges in the coronary arteries coronary arteries myocardial myocardial infarct (Heart attack).infarct (Heart attack).

If the embolism lodges in an artery in If the embolism lodges in an artery in the brain the brain stroke stroke

If the embolism lodges in the lungs If the embolism lodges in the lungs pulmonary embolism pulmonary embolism

ANGIOGRAMANGIOGRAM

An An ANGIOGRAMANGIOGRAM is a procedure to is a procedure to inject dye into the arteries and x-ray inject dye into the arteries and x-ray to see if there is narrowing (sclerosis) to see if there is narrowing (sclerosis) of a vessel. This can be done of a vessel. This can be done anywhere in the body that is of anywhere in the body that is of interest, but frequently it is done to interest, but frequently it is done to check the coronary arteries. check the coronary arteries.

ANGIOGRAMANGIOGRAM

If an artery is too narrow, an If an artery is too narrow, an ANGIOPLASTYANGIOPLASTY can be performed to can be performed to open it up. This involves sticking a open it up. This involves sticking a balloon into the artery and inflating balloon into the artery and inflating it, causing the vessel to enlarge a it, causing the vessel to enlarge a little to increase blood flow. This can little to increase blood flow. This can be done anywhere in the body, but is be done anywhere in the body, but is frequently done in coronary arteries.frequently done in coronary arteries.

CORONARY BYPASSCORONARY BYPASS

For a coronary artery that has become For a coronary artery that has become extremely narrow from plaques, you can extremely narrow from plaques, you can do a do a CORONARY BYPASSCORONARY BYPASS..

People who exercise have the same People who exercise have the same number of heart attacks as those who number of heart attacks as those who don’t, but they tend to survive them.don’t, but they tend to survive them.

VENTRICULAR FIBRILLATIONVENTRICULAR FIBRILLATION

Even a small clot can be a problem. If Even a small clot can be a problem. If it happens to enter the interior of the it happens to enter the interior of the heart and lodge in the wall of the heart and lodge in the wall of the atrium, it can block the conduction of atrium, it can block the conduction of the signal of the AV node the signal of the AV node VENTRICULAR FIBRILLATION.VENTRICULAR FIBRILLATION.

ANEURYSMANEURYSM High blood pressure is due to high High blood pressure is due to high

pressure of blood against the walls of the pressure of blood against the walls of the blood vessels; the blood vessels blood vessels; the blood vessels compensate by developing a thicker wall. compensate by developing a thicker wall.

The vessels can no longer expand during The vessels can no longer expand during systole, so the vessel gets thicker and systole, so the vessel gets thicker and thicker, and the blood pressure goes up thicker, and the blood pressure goes up more. more.

If the blood pressure gets too high, an If the blood pressure gets too high, an ANEURYSMANEURYSM can form, which is a can form, which is a weakening in the wall of the blood vessel, weakening in the wall of the blood vessel, causing it to expand like a balloon. causing it to expand like a balloon.

Coronary artery disease Coronary artery disease termsterms

Coronary artery diseaseCoronary artery disease– Atherosclerosis – fatty depositsAtherosclerosis – fatty deposits– Angina pectoris – chest painAngina pectoris – chest pain– Myocardial infarction – blocked coronary Myocardial infarction – blocked coronary

arteryartery– Silent ischemia – lack of blood flow that Silent ischemia – lack of blood flow that

happens to not cause any pain or other happens to not cause any pain or other symptoms; leads to an unexpected heart symptoms; leads to an unexpected heart attack.attack.

– Stroke – ruptured blood vessel in the Stroke – ruptured blood vessel in the brain. Also called Cerebral Vascular brain. Also called Cerebral Vascular Accident (CVA)Accident (CVA)

Other Heart ConditionsOther Heart Conditions

Congestive Heart failureCongestive Heart failure– Progressive weakening of the heartProgressive weakening of the heart– Blood backs up into lungs (may cough Blood backs up into lungs (may cough

up blood)up blood)– Cannot meet the body’s demands for Cannot meet the body’s demands for

oxygenated bloodoxygenated blood Hypertrophic cardiomyopathyHypertrophic cardiomyopathy

– Congenital condition where the walls of Congenital condition where the walls of the left ventricle are so thick that the the left ventricle are so thick that the lumen is too small to hold much blood. lumen is too small to hold much blood.

Disorders of ConductionDisorders of Conduction

Ventricular fibrillation Ventricular fibrillation – Rapid, random firing of electrical Rapid, random firing of electrical

impulses in the ventricles of the AV impulses in the ventricles of the AV nodenode

Atrial fibrillation Atrial fibrillation – Rapid, random firing of electrical Rapid, random firing of electrical

impulses of the SA nodeimpulses of the SA node

Most Common Heart Most Common Heart Problems Problems

ATHEROSCLEROSISATHEROSCLEROSIS VENTRICULAR FIBRILLATIONVENTRICULAR FIBRILLATION Congestive heart failure Congestive heart failure Hypertrophic cardiomyopathyHypertrophic cardiomyopathy

FORAMEN OVALEFORAMEN OVALE The lung tissue needs some oxygenated blood, The lung tissue needs some oxygenated blood,

but only a little. Therefore, there is an opening but only a little. Therefore, there is an opening from the right to the left atrium called the from the right to the left atrium called the FORAMEN OVALE FORAMEN OVALE which shunts blood from the which shunts blood from the right to the left side of the heart to bypass the right to the left side of the heart to bypass the lungs.lungs.

There is a foramen ovale in the skull and another There is a foramen ovale in the skull and another one in the heart. The foramen ovale in the heart one in the heart. The foramen ovale in the heart normally closes shortly after birth, and is then normally closes shortly after birth, and is then called the called the FOSSA OVALISFOSSA OVALIS..

A ‘blue baby” has low oxygen levels in the blood A ‘blue baby” has low oxygen levels in the blood that may be due to failure of the foramen ovale to that may be due to failure of the foramen ovale to close at birth: close at birth: Patent foramen ovale.Patent foramen ovale.

DUCTUS ARTERIOSISDUCTUS ARTERIOSIS

Another shunt: between the pulmonary Another shunt: between the pulmonary artery and the aortic arch so that most of artery and the aortic arch so that most of the blood bypasses the immature lungs the blood bypasses the immature lungs Therefore, there are two shunts to take Therefore, there are two shunts to take blood away from the lungs.blood away from the lungs.

If the electrical signals from the atria were If the electrical signals from the atria were conducted directly into the ventricles across conducted directly into the ventricles across the AV septum, the ventricles would start to the AV septum, the ventricles would start to contract at the top (base). Then the blood contract at the top (base). Then the blood would be squeezed downward and trapped would be squeezed downward and trapped at the bottom of the ventricle. at the bottom of the ventricle.

The apex to base contraction squeezes blood The apex to base contraction squeezes blood toward the arterial opening at the base of toward the arterial opening at the base of the heart.the heart.

The AV node also delays the transmission of The AV node also delays the transmission of action potentials slightly, allowing the atria action potentials slightly, allowing the atria to complete their contraction before the to complete their contraction before the ventricles begin their contraction. This ventricles begin their contraction. This AV AV nodal delaynodal delay is accomplished by the is accomplished by the naturally slow conduction through the AV naturally slow conduction through the AV node cells. (node cells. (Why are they slow Why are they slow conductors? Small diameter cells, conductors? Small diameter cells, fewer channelsfewer channels))

Fibers within the Fibers within the heartheart

Specialized FibersSpecialized Fibers– are the fibers that can spontaneously initiate are the fibers that can spontaneously initiate

an AP all by themselves!an AP all by themselves!– The AP will spread to all other fibers via gap The AP will spread to all other fibers via gap

junctionsjunctions– AKA “leading cells”AKA “leading cells”– But they are also muscle, so they do contract, But they are also muscle, so they do contract,

albeit feebly!albeit feebly!– They are not nerves!!!!They are not nerves!!!!

Contractile FibersContractile Fibers– These maintain their RMP forever, unless These maintain their RMP forever, unless

brought to threshold by some other cellbrought to threshold by some other cell– They cannot generate an AP by themselvesThey cannot generate an AP by themselves– AKA “following cells”AKA “following cells”– But they do have gap junctions, so once But they do have gap junctions, so once

they’re triggered, they will help spread the AP they’re triggered, they will help spread the AP to neighbors.to neighbors.

Pathway of HeartbeatPathway of Heartbeat Begins in the sinoatrial Begins in the sinoatrial (S-(S-

A) nodeA) node Internodal pathwayInternodal pathway to to

atrioventricular (A-V) node atrioventricular (A-V) node Impulse delayed in Impulse delayed in A-V A-V

nodenode (allows atria to (allows atria to contract before ventricles)contract before ventricles)

A-V bundleA-V bundle takes impulse takes impulse into ventriclesinto ventricles

Left and right bundles of Left and right bundles of Purkinje fibersPurkinje fibers take take impulses to all parts of impulses to all parts of ventriclesventricles

KEY Red = specialized cells;

all else = contractile cells

How can these Specialized How can these Specialized fibers spontaneously “fire?”fibers spontaneously “fire?”

Can’t hold stable resting Can’t hold stable resting membrane potentialmembrane potential

Potentials drift (gradual Potentials drift (gradual depolarization) depolarization)

During this time, they have a During this time, they have a gradually increasing perm to gradually increasing perm to Na+Na+ and less leaky to K+ and less leaky to K+ (more “+” inside causes cell (more “+” inside causes cell to depolarize, remember?). to depolarize, remember?). OnlyOnly specialized fibers of the specialized fibers of the heart can depolarize on their heart can depolarize on their own.own.

This is what gives the heart This is what gives the heart it’s rhythm.it’s rhythm. Na+

Specialized fibers Specialized fibers of conductive of conductive

systemsystem These rhythms can These rhythms can

ALSO be modified ALSO be modified by the ANSby the ANS

Neurotransmitters can Neurotransmitters can cause faster or slower rise cause faster or slower rise to threshold by altering ion to threshold by altering ion permeability.permeability.

Acetylcholine (ACh) slows Acetylcholine (ACh) slows the heart rate the heart rate (parasympathetic division (parasympathetic division of ANS)of ANS)

Norepinephrine (NE) Norepinephrine (NE) speeds up the heart rate speeds up the heart rate (sympathetic division of (sympathetic division of ANS)ANS)

K+ efflux

Sympathetic – speeds heart rate by Sympathetic – speeds heart rate by Ca++ & Na+ channel influx and Ca++ & Na+ channel influx and K+ K+ permeability/effluxpermeability/efflux

((increases sodium and calcium permeabilityincreases sodium and calcium permeability)) Parasympathetic – slows rate by Parasympathetic – slows rate by K+ efflux & K+ efflux & Ca++ influx ( Ca++ influx (decreases sodium and decreases sodium and

calcium permeabilitycalcium permeability))

Which neurotransmitter will cause your heart to pound rapidly?Which neurotransmitter will cause your heart to pound rapidly?– NorepinephrineNorepinephrine

Sympathetic and Sympathetic and ParasympatheticParasympathetic

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Blood Flow (L/min)Blood Flow (L/min)

Blood flow Blood flow is the quantity is the quantity of blood that passes a of blood that passes a given point in the given point in the circulation in a given circulation in a given period of time.period of time.

Overall flow in the Overall flow in the circulation of an adult is 5 circulation of an adult is 5 liters/min which is the liters/min which is the cardiac output.cardiac output.

HR = heart rateHR = heart rate

SV = stroke volumeSV = stroke volume

CO= HR X SVCO= HR X SV

70 b/min x 70 ml/beat 70 b/min x 70 ml/beat =4900ml/min=4900ml/min

Ventricular Ejection Volume = Ventricular Ejection Volume = Stroke VolumeStroke Volume

Stroke Volume (SV)Stroke Volume (SV)– amount ejected, ~ 70 amount ejected, ~ 70

mlml End Diastolic Volume (EDV)End Diastolic Volume (EDV) SV/EDV= ejection fraction, SV/EDV= ejection fraction,

– at rest ~ 60% at rest ~ 60% – during vigorous during vigorous

exercise as high as 90%exercise as high as 90%– diseased heart < 50%diseased heart < 50%

End-systolic volume: End-systolic volume: amount left in heart (50ml)amount left in heart (50ml)

Cardiac Output (CO)Cardiac Output (CO) Amount ejected by a ventricle in Amount ejected by a ventricle in 1 minute1 minute CO = HR x SVCO = HR x SV Resting values, 4- 6 L/minResting values, 4- 6 L/min Vigorous exercise, 21 L/min Vigorous exercise, 21 L/min Cardiac reserve: difference Cardiac reserve: difference

between maximum and resting between maximum and resting COCO

If resting CO = 6 L/min and after exercise increases to 21 L/min, what is the cardiac reserve?CR = 21 – 6CR = 15 L/min

Volumes and Fraction

• End diastolic volume = 120 ml

• End systolic volume = 50 ml

• Ejection volume (stroke volume) = 70 ml

• Ejection fraction = 70ml/120ml = 58% (normally 60%)

• If heart rate (HR) is 70 beats/minute, what is cardiac output?

• Cardiac output = HR * stroke volume = 70/min. * 70 ml

= 4900ml/min.

Questions

• If EDV = 120 ml and ESV = 50 ml:

• What is the SV?• 120-50 = 70 ml

• What is the EF?• 70/120 = 58%

• What is the CO if HR is 70 bpm?• 70/bpm * 70 ml = 4900ml/min.

Ohm’s Law: Q=Ohm’s Law: Q=P/RP/R FlowFlow (Q) through a blood vessel which is the same (Q) through a blood vessel which is the same

thing as saying Cardiac Output (CO). It is usually 5.thing as saying Cardiac Output (CO). It is usually 5. The pressure difference (The pressure difference (P) is normally 100.P) is normally 100. ResistanceResistance (R) of the vessel needs to be calculated. (R) of the vessel needs to be calculated. Therefore, applying Ohm’s Law (Q=Therefore, applying Ohm’s Law (Q=P/R) to a P/R) to a

normalnormal person, we get this: person, we get this:5 = 100/R5 = 100/RSolving for R:Solving for R:R = 100/5R = 100/5R = 20 PRUR = 20 PRU

That means that the normal amount of resistance in That means that the normal amount of resistance in the blood vessels is 20 PRU (peripheral resistance the blood vessels is 20 PRU (peripheral resistance units).units).

Overall, the values for a normal person are:Overall, the values for a normal person are:5 = 100/205 = 100/20

Factors Affecting COFactors Affecting CO Blood viscosity (decreases CO)Blood viscosity (decreases CO) Total vessel length (longer Total vessel length (longer

decreases CO)decreases CO) Vessel diameter (larger increases Vessel diameter (larger increases

CO)CO)

Regulation of Blood FlowRegulation of Blood Flow

Vasodilators Vasodilators increase blood increase blood flowflow

Vasoconstrictors Vasoconstrictors decrease blood decrease blood flowflow

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Vasomotor control: Sympathetic Vasomotor control: Sympathetic InnervationInnervation

of Blood Vesselsof Blood Vessels SympatheticSympathetic nerve fibers nerve fibers innervate innervate all all vessels vessels exceptexcept capillaries and precapillary capillaries and precapillary sphincters (precapillary sphincters (precapillary

sphincters follow local control)sphincters follow local control)

Innervation of small arteries and Innervation of small arteries and arterioles allow sympathetic arterioles allow sympathetic nerves to nerves to increase vascular increase vascular resistance.resistance.

Large veins Large veins and and the heart the heart are are also sympathetically innervated.also sympathetically innervated.

Figure 18-2; Guyton and Hall

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Baroreceptors respond to Baroreceptors respond to changeschanges in in arterial pressure.arterial pressure.

As blood pressureAs blood pressure increases increases the number of impulses from carotid the number of impulses from carotid sinus sinus increasesincreases which results in: which results in:1) inhibition of vasoconstricton (so the blood vessels 1) inhibition of vasoconstricton (so the blood vessels

dilate, which lowers blood pressure)dilate, which lowers blood pressure)2) activation of the vagal center (lowers blood pressure)2) activation of the vagal center (lowers blood pressure)

As blood pressure decreases the number of impulses from carotid sinus decreases which results in:

1) Increased sympathetic activity (which causes blood vessels to constrict)2) vasoconstricton (which raises blood pressure)

Drugs Affecting CODrugs Affecting CO AtropineAtropine- blocks - blocks

parasympathetic system parasympathetic system (increase in sympathetic (increase in sympathetic responses)responses)

PilocarpinePilocarpine- drug that causes - drug that causes skeletal muscle neurons to skeletal muscle neurons to release ACH, which release ACH, which decreases heart rate.decreases heart rate.

PropranalolPropranalol- blocks - blocks sympathetic effect of heart. sympathetic effect of heart. This causes decreased heart This causes decreased heart rate and force of contraction, rate and force of contraction, and lowers blood pressure. and lowers blood pressure.

Drugs Affecting CO (2)Drugs Affecting CO (2) Digoxin (shorter ½ Digoxin (shorter ½

life) or Digitoxinlife) or Digitoxin- - come from group of come from group of drugs derived from drugs derived from digitalis. Digitalis digitalis. Digitalis derived from derived from foxglove plant. Slows foxglove plant. Slows heart rate but heart rate but increases force of increases force of contraction. Is only contraction. Is only drug with this effect drug with this effect on heart. on heart. – Disadvantage of using Disadvantage of using

digitalis is that it’s digitalis is that it’s extremely toxic. The extremely toxic. The optimal dose is very close optimal dose is very close to lethal dose- stops heartto lethal dose- stops heart

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Causes of EdemaCauses of Edema Excessive accumulation of Excessive accumulation of

tissue fluid.tissue fluid. Edema may result from:Edema may result from:

– High arterial blood High arterial blood pressure.pressure.

– Venous obstruction.Venous obstruction.– Leakage of plasma proteins Leakage of plasma proteins

into interstitial fluid.into interstitial fluid.– Valve problemsValve problems– Cardiac failureCardiac failure– Decreased plasma protein.Decreased plasma protein.– Obstruction of lymphatic Obstruction of lymphatic

drainage. drainage. – ElephantiasisElephantiasis

Control of Hormones Release: Three MechanismsControl of Hormones Release: Three Mechanisms

Figure 25.2a-c

The Pituitary Gland The Pituitary Gland

Secretes nine major hormonesSecretes nine major hormones Attached to the hypothalamus by the Attached to the hypothalamus by the

infundibulum infundibulum Two basic divisions of the pituitary Two basic divisions of the pituitary

glandgland– Adenohypophysis (anterior lobe)Adenohypophysis (anterior lobe)– Neurohypophysis (posterior lobe)Neurohypophysis (posterior lobe)

The AdenhypophysisThe Adenhypophysis

Growth hormone (GH)Growth hormone (GH)– Causes the body to growCauses the body to grow

Prolactin (PRL)Prolactin (PRL)– Stimulates lactation (milk production) in Stimulates lactation (milk production) in

femalesfemales– Produces desire to cry Produces desire to cry – Decreased in adolescent males so it Decreased in adolescent males so it

decreases desire to crydecreases desire to cry

Thyroid Stimulating Hormone (TSH)Thyroid Stimulating Hormone (TSH)– Causes the thyroid gland to release thyroid Causes the thyroid gland to release thyroid

hormonehormone

The AdenhypophysisThe Adenhypophysis Adrenocorticotropic hormone (ACTH)Adrenocorticotropic hormone (ACTH)

– Acts on adrenal cortex to stimulate the release of Acts on adrenal cortex to stimulate the release of cortisol cortisol

– Helps people cope with stressHelps people cope with stress Melanocyte-stimulating hormone (MSH)Melanocyte-stimulating hormone (MSH)

– Darkens skin pigmentationDarkens skin pigmentation– Increases during pregnancyIncreases during pregnancy– Also has effects on appetite and sexual arousalAlso has effects on appetite and sexual arousal

Follicle-stimulating hormone (FSH) Follicle-stimulating hormone (FSH) – Present in males and females, affects bothPresent in males and females, affects both– Stimulates maturation of sex cellsStimulates maturation of sex cells

Luteinizing hormone (LH)Luteinizing hormone (LH)– Induces ovulationInduces ovulation

Study Tip to remember the hormones Study Tip to remember the hormones secreted by the pituitary glandsecreted by the pituitary gland

““Melons grow and produce through late fall” stands for the Melons grow and produce through late fall” stands for the hormones made in the anterior pituitary. hormones made in the anterior pituitary.

Melanocyte stimulating hormone (MSH)Melanocyte stimulating hormone (MSH) Growth Hormone (GH) Growth Hormone (GH) Adrenal corticotropic Hormone (ACTH)Adrenal corticotropic Hormone (ACTH) Prolactin (stimulates the production of breast milk)Prolactin (stimulates the production of breast milk) Thyroid stimulating hormone (TSH)Thyroid stimulating hormone (TSH) Luteinizing Hormone (LH) Luteinizing Hormone (LH) Follicle stimulating Hormone (FSH)Follicle stimulating Hormone (FSH)

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The NeurohypophysisThe Neurohypophysis

This is a continuation of the brain; cell This is a continuation of the brain; cell bodies of special neurons in the bodies of special neurons in the hypothalamus have axons which go to hypothalamus have axons which go to the neurohypophysis and synapse on the neurohypophysis and synapse on capillaries there. Instead of releasing capillaries there. Instead of releasing neurotransmitter, they release neurotransmitter, they release hormones. hormones.

Oxytocin Oxytocin – Childbirth contractionsChildbirth contractions

Antidiuretic hormone (ADH)Antidiuretic hormone (ADH)– Signals kidneys to increase water Signals kidneys to increase water

reabsorptionreabsorption

Figure 25.6

Hypothalamus RegulationHypothalamus Regulation The hypothalamus produces hormones The hypothalamus produces hormones

which affect the pituitary, for example:which affect the pituitary, for example: Thyroid Stimulating Hormone Releasing Hormone Thyroid Stimulating Hormone Releasing Hormone

(TSH-RH)(TSH-RH)– Causes adenohypophysis to secrete TSHCauses adenohypophysis to secrete TSH– TSH affects thyroid gland to secrete THTSH affects thyroid gland to secrete TH

Thyroid Stimulating Hormone Inhibiting Hormone Thyroid Stimulating Hormone Inhibiting Hormone (TSH-IH)(TSH-IH)– Causes adenohypophysis to stop secreting TSH Causes adenohypophysis to stop secreting TSH

so thyroid gland stops secreting thyroid so thyroid gland stops secreting thyroid hormonehormone

The hypothalamus affects the adenohypophysis, The hypothalamus affects the adenohypophysis, and that’s about it.and that’s about it.

Pituitary DisordersPituitary Disorders

Gigantism and AcromegalyGigantism and Acromegaly– Hypersecretion of GH in childrenHypersecretion of GH in children– Gigantism is overall growthGigantism is overall growth– Acromegaly is enlarged hands and feetAcromegaly is enlarged hands and feet

Pituitary dwarfismPituitary dwarfism– Hyposecretion of GHHyposecretion of GH– Proportions are normal, overall size is smallProportions are normal, overall size is small

Diabetes insipidusDiabetes insipidus– Not enough ADH (anti-diuretic hormone; a Not enough ADH (anti-diuretic hormone; a

diuretic takes out excess fluid from the body) diuretic takes out excess fluid from the body)

The Thyroid GlandThe Thyroid Gland

Thyroid hormone (TH)Thyroid hormone (TH)– Acts on most cells of the bodyActs on most cells of the body– Increases metabolic rate Increases metabolic rate – Controlled by humeral (blood) elementsControlled by humeral (blood) elements– Iodine is needed to make THIodine is needed to make TH

Calcitonin Calcitonin – Lowers blood calcium levels in childrenLowers blood calcium levels in children– Slows osteoclasts to allow for bone depositionSlows osteoclasts to allow for bone deposition(Vitamin D is synthesized and secreted by bone (Vitamin D is synthesized and secreted by bone

cells) cells)

Thyroid HormoneThyroid Hormone The major stimulus for the release of thyroid The major stimulus for the release of thyroid

hormone is humeral (blood elements tell the body hormone is humeral (blood elements tell the body it needs more thyroid hormone). it needs more thyroid hormone).

Thyroid hormone is partly made of iodine. Iodine Thyroid hormone is partly made of iodine. Iodine is essential for the formation of thyroxin. If a is essential for the formation of thyroxin. If a person doesn’t eat enough iodine, they can’t person doesn’t eat enough iodine, they can’t make thyroid hormone. make thyroid hormone.

The hypothalamus responds by putting out more The hypothalamus responds by putting out more TSH-RH.TSH-RH.

The pituitary will respond by releasing TSH. The pituitary will respond by releasing TSH. But the thyroid can’t respond by releasing TH if it But the thyroid can’t respond by releasing TH if it

does not have the iodine to make the hormone, does not have the iodine to make the hormone, so it the size of the follicle grows so it the size of the follicle grows gland grows gland grows GOITERGOITER. .

Problems with ThyroidProblems with Thyroid

GoiterGoiter– Too little iodine in the dietToo little iodine in the diet

Hyperthyroidism (Graves’ Disease)Hyperthyroidism (Graves’ Disease)– Caused by autoimmune disorderCaused by autoimmune disorder– Leads to nervousness, weight loss, Leads to nervousness, weight loss,

sweating, and rapid heart ratesweating, and rapid heart rate HypothyroidismHypothyroidism

– Decreases metabolism, causes obesityDecreases metabolism, causes obesity

HypothyroidismHypothyroidism

Hashimodo’s ThyroiditisHashimodo’s Thyroiditis– Antibodies attack and destroy thyroid Antibodies attack and destroy thyroid

tissuetissue– Low metabolic rate and weight gain are Low metabolic rate and weight gain are

common symptomscommon symptoms Cretinism – hypothyroidism in Cretinism – hypothyroidism in

childrenchildren– Short, disproportionate body, thick Short, disproportionate body, thick

tongue and mental retardation tongue and mental retardation

Parathyroid GlandsParathyroid Glands

Parathyroid hormone (PTH)Parathyroid hormone (PTH) Increases blood concentration of CaIncreases blood concentration of Ca2+2+

Tells osteoclasts to release calcium from boneTells osteoclasts to release calcium from bone Tells kidneys to decrease secretion of calciumTells kidneys to decrease secretion of calcium Activates vitamin D which increases calcium uptake Activates vitamin D which increases calcium uptake

by intestinesby intestines Does NOT metabolize calciumDoes NOT metabolize calcium

THYMUS GLANDTHYMUS GLAND

Hormones produced by this organ Hormones produced by this organ stimulate the production of T cells.stimulate the production of T cells.

The Adrenal GlandsThe Adrenal Glands

Located on the superior surface of Located on the superior surface of the kidneysthe kidneys

Two endocrine glands in oneTwo endocrine glands in one– Adrenal cortex – bulk of the adrenal Adrenal cortex – bulk of the adrenal

glandgland– Adrenal medulla – a knot of nervous Adrenal medulla – a knot of nervous

tissue within the glandtissue within the gland

The Adrenal CortexThe Adrenal Cortex Secretes a variety of hormones; All are steroidsSecretes a variety of hormones; All are steroids CORTISONE CORTISONE reduces inflammation reduces inflammation CORTISOL CORTISOL helps the body deal with stressful situations helps the body deal with stressful situations

like fasting, anxiety, trauma, and infection. It keeps the like fasting, anxiety, trauma, and infection. It keeps the blood protein and glucose levels high enough to support blood protein and glucose levels high enough to support

the brain’s activities and affects the metabolic rate.the brain’s activities and affects the metabolic rate. When the brain perceives a stressful situation, the When the brain perceives a stressful situation, the hypothalamus tells the pituitary to secrete ACTH, which hypothalamus tells the pituitary to secrete ACTH, which travels to the adrenal gland and signals it to release travels to the adrenal gland and signals it to release cortisol to most of the cells of the body.cortisol to most of the cells of the body.

ALDOSTERONE ALDOSTERONE increases blood volume during increases blood volume during hemorrhage or drop in blood pressure. It causes kidney to hemorrhage or drop in blood pressure. It causes kidney to reabsorb more sodium; water follows with it, so the blood reabsorb more sodium; water follows with it, so the blood volume increases.volume increases.

SEX HORMONES SEX HORMONES for the opposite sex: Males produce for the opposite sex: Males produce estrogen here, and females produce testosterone. estrogen here, and females produce testosterone.

The Adrenal MedullaThe Adrenal Medulla

Secretes catecholamines:Secretes catecholamines:ADRENALIN ADRENALIN (AKA epinephrine “above the (AKA epinephrine “above the

kidney”; Greek). kidney”; Greek).

This is the neurotransmitter for the sympathetic This is the neurotransmitter for the sympathetic nervous system. nervous system.

The adrenal medulla also has sympathetic The adrenal medulla also has sympathetic neurons which synapse on it, so when you are neurons which synapse on it, so when you are spooked, the neurons fire and stimulates the spooked, the neurons fire and stimulates the adrenal medulla to release more epinephrine adrenal medulla to release more epinephrine to increase the effects of the sympathetic to increase the effects of the sympathetic nervous system.nervous system.

Adrenal Gland DisordersAdrenal Gland Disorders

Cushing’s syndromeCushing’s syndrome– hypersecretion of cortisol hypersecretion of cortisol – Round “moon” face and “buffalo hump”Round “moon” face and “buffalo hump”

Addison’s diseaseAddison’s disease– Hyposecretion of cortisolHyposecretion of cortisol– Low blood pressure resultsLow blood pressure results– Also get hyperpigmentation Also get hyperpigmentation

The Pineal GlandThe Pineal Gland

Pinealocytes secrete melatonin Pinealocytes secrete melatonin – A hormone that regulates circadian A hormone that regulates circadian

rhythms (sense of daytime and night; rhythms (sense of daytime and night; it regulates sleep cycle)it regulates sleep cycle)

Endocrine Hormones Endocrine Hormones of the Pancreasof the Pancreas

GlucagonGlucagon Signals liver to break down glycogen into Signals liver to break down glycogen into

glucoseglucose Raises blood sugarRaises blood sugar

Insulin Insulin Signals most body cells to take up glucose Signals most body cells to take up glucose

from the bloodfrom the blood Promotes storage of glucose as glycogen in Promotes storage of glucose as glycogen in

liverliver Lowers blood sugarLowers blood sugar

DiabetesDiabetes

DIABETES INSIPIDUSDIABETES INSIPIDUS– pituitary gland does not secrete antidiuretic hormone, or pituitary gland does not secrete antidiuretic hormone, or

the kidney does not respond to the hormone. the kidney does not respond to the hormone.

DIABETES MELLITUSDIABETES MELLITUS – hereditary lack of insulin secretion in the pancreas, or hereditary lack of insulin secretion in the pancreas, or

resistance to insulin by the body’s cells.resistance to insulin by the body’s cells. Type I diabetesType I diabetes (insulin dependent, develops in children) (insulin dependent, develops in children)

– Destruction of pancreatic islets by autoimmune Destruction of pancreatic islets by autoimmune disorders. disorders.

– Need insulin injections daily throughout life.Need insulin injections daily throughout life. Type II diabetesType II diabetes (not insulin dependent, develops in (not insulin dependent, develops in

adults)adults)– Consequence of obesity: cells are less sensitive to Consequence of obesity: cells are less sensitive to

insulin. insulin. – Initially treated with diet and exercise.Initially treated with diet and exercise.– Oral medicines or injected insulin may be needed.Oral medicines or injected insulin may be needed.

The GonadsThe Gonads

OvariesOvaries– Secrete progesteroneSecrete progesterone

Prepares uterus for pregnancyPrepares uterus for pregnancy

– Secrete estrogenSecrete estrogen Female secondary characteristicsFemale secondary characteristics Stores enough for several monthsStores enough for several months

TestesTestes– Secrete androgens (e.g. testosterone)Secrete androgens (e.g. testosterone)

Promotes the formation of spermPromotes the formation of sperm Maintains secondary sex characteristicsMaintains secondary sex characteristics Testes are the primary sex organs in the male, NOT Testes are the primary sex organs in the male, NOT

the penisthe penis

This is what happens in the body:This is what happens in the body:

Hypothalamus (the boss) makes Hypothalamus (the boss) makes TSH-RHTSH-RH (thyroid stimulating (thyroid stimulating hormone releasing hormone)hormone releasing hormone)

Pituitary (the manager) makes Pituitary (the manager) makes TSHTSH (thyroid stimulating hormone) (thyroid stimulating hormone)

Thyroid gland (the worker) Thyroid gland (the worker) makes THmakes TH (thyroid hormone) (thyroid hormone)

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Thyroid HormoneThyroid Hormone The hypothalamus releases its hormone (TSH-RH) to The hypothalamus releases its hormone (TSH-RH) to

the pituitary, telling the pituitary to release its the pituitary, telling the pituitary to release its hormone (TSH), which tells the thyroid gland to hormone (TSH), which tells the thyroid gland to release thyroid hormone (TH). release thyroid hormone (TH).

When thyroid hormone is released, it will circulate When thyroid hormone is released, it will circulate throughout the body, causing an increase in throughout the body, causing an increase in metabolism in all of those cells. Some of the TH will metabolism in all of those cells. Some of the TH will bind to receptors in the hypothalamus, and then the bind to receptors in the hypothalamus, and then the hypothalamus knows there is enough TH, and it will hypothalamus knows there is enough TH, and it will stop releasing TSH-RH. Until the receptors in the stop releasing TSH-RH. Until the receptors in the hypothalamus are bound with the resulting thyroid hypothalamus are bound with the resulting thyroid hormone, the hypothalamus is not satisfied that there hormone, the hypothalamus is not satisfied that there is enough thyroid hormone present. is enough thyroid hormone present.

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What if the hypothalamus released its signal and What if the hypothalamus released its signal and the thyroid released too much hormone?the thyroid released too much hormone?

The hypothalamus will stop secreting The hypothalamus will stop secreting its releasing hormone. This is a its releasing hormone. This is a negative feedback signal. negative feedback signal.

  When very few TH receptors are When very few TH receptors are bound on the hypothalamus, it will bound on the hypothalamus, it will keep releasing its hormone. When its keep releasing its hormone. When its thyroid receptors are saturated, will thyroid receptors are saturated, will stop.stop.

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What if a gland disobeys the negative What if a gland disobeys the negative feedback?feedback?

Example: Thyroid gland is impaired by a tumor. Example: Thyroid gland is impaired by a tumor. A thyroid tumor might cause it to over-secrete or under-A thyroid tumor might cause it to over-secrete or under-

secrete TH. secrete TH. Under-secreting thyroid tumor:Under-secreting thyroid tumor: what happens to the what happens to the

other hormone levels? Start with the problem area (in this other hormone levels? Start with the problem area (in this case, the thyroid is the place with the tumor), and then case, the thyroid is the place with the tumor), and then evaluate the other glands.evaluate the other glands. (Start with the problem area, (Start with the problem area, the thyroid gland)the thyroid gland)– TH will be low (hypothyroidism)TH will be low (hypothyroidism)– TSH-RH will be high, since only a few hypothalamus TSH-RH will be high, since only a few hypothalamus

receptors are boundreceptors are bound– TSH levels will be high. TSH levels will be high.

Over-secreting thyroid tumorOver-secreting thyroid tumor: : – TH will be high (hyperthyroidism)TH will be high (hyperthyroidism)– TSH-RH will be lowTSH-RH will be low– TSH levels will be lowTSH levels will be low. This combination tells you the . This combination tells you the

source of the problem is the thyroidsource of the problem is the thyroid.. 146146

Another Example: Pituitary Another Example: Pituitary tumortumor

  Under-secreting pituitary tumor (Start with the Under-secreting pituitary tumor (Start with the problem area, the pituitary)problem area, the pituitary)– TSH is lowTSH is low– TH is low (hypothyroidism)TH is low (hypothyroidism)– TSH-RH is highTSH-RH is high

Over-secreting pituitary tumorOver-secreting pituitary tumor– TSH is highTSH is high– TH is high (hyperthyroidism)TH is high (hyperthyroidism)– TSH-RH is low TSH-RH is low

   NOTE: If the problem is the TSH, we don’t bother injecting NOTE: If the problem is the TSH, we don’t bother injecting

TSH, we just give the hormone that is lacking: Thyroid TSH, we just give the hormone that is lacking: Thyroid hormone. hormone.

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Example: Hypothalamic Example: Hypothalamic TumorTumor

  Under-secreting hypothalamic tumor Under-secreting hypothalamic tumor (Start with the problem area, the (Start with the problem area, the hypothalamus)hypothalamus)– TSH-RH is lowTSH-RH is low– TSH is lowTSH is low– TH is low (hypothyroidism)TH is low (hypothyroidism)

Over-secreting hypothalamic tumorOver-secreting hypothalamic tumor– TSH-RH is high TSH-RH is high – TSH is highTSH is high– TH is high (hyperthyroidism)TH is high (hyperthyroidism)

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Other Hormone CyclesOther Hormone Cycles The adrenal cortex has the same The adrenal cortex has the same

cycle as thyroid hormone; it needs cycle as thyroid hormone; it needs ACTH-RH (adrenocorticotropic ACTH-RH (adrenocorticotropic releasing hormone), ACTH, CH releasing hormone), ACTH, CH (cortisol hormone).(cortisol hormone).

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Hormone LevelsHormone Levels

Know what would happen to the three Know what would happen to the three hormone levels (TSH-RH, TSH, TH) in hormone levels (TSH-RH, TSH, TH) in the following conditions:the following conditions:

Antibodies attacking thyroid gland, Antibodies attacking thyroid gland, destroying the glanddestroying the gland

Antibodies binding to the TSH receptor, Antibodies binding to the TSH receptor, stimulating itstimulating it

Graves’ DiseaseGraves’ Disease Hashimoto’s ThyroiditisHashimoto’s Thyroiditis

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Regulation of Blood Glucose Regulation of Blood Glucose LevelsLevels

When blood glucose is high, the pancreas secretes When blood glucose is high, the pancreas secretes insulininsulin, , which tells the cells to take in the sugar from the bloodstream. which tells the cells to take in the sugar from the bloodstream. If the blood sugar levels remain high, the excess sugar is taken If the blood sugar levels remain high, the excess sugar is taken to the liver and converted to glycogen for storage.to the liver and converted to glycogen for storage.

When blood glucose is low, the pancreas secretes When blood glucose is low, the pancreas secretes glucagonglucagon, , which tells the liver to take the glycogen and break it back which tells the liver to take the glycogen and break it back down into glucose and release it into the bloodstream.down into glucose and release it into the bloodstream.

Gluconeogenesis is when the liver takes fatty acids (leftover Gluconeogenesis is when the liver takes fatty acids (leftover from fat metabolism) and joins them to amino acids (from from fat metabolism) and joins them to amino acids (from broken down proteins), and makes new glucose molecules that broken down proteins), and makes new glucose molecules that you did not get from eating glucose. These new glucose you did not get from eating glucose. These new glucose molecules are then released into the bloodstream to elevate molecules are then released into the bloodstream to elevate blood glucose levels.blood glucose levels.

Summary:Summary:– When blood glucose is high, When blood glucose is high, insulininsulin lowers blood glucose levels. lowers blood glucose levels.– When blood glucose is low, glucagon causes When blood glucose is low, glucagon causes glycogen breakdown glycogen breakdown and and

gluconeogenesis gluconeogenesis toto raise blood glucose levels.raise blood glucose levels.

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Hyperthyroidism Hyperthyroidism (Most commonly caused by Graves (Most commonly caused by Graves

Disease)Disease)

Signs include thinness, eyes that stick Signs include thinness, eyes that stick out like a bug (exophthalmoses). out like a bug (exophthalmoses).

Graves Disease is a person who has Graves Disease is a person who has antibodies that bind to thyroid gland, antibodies that bind to thyroid gland, tricks it into making tricks it into making excess TH, excess TH, while TSH-RH and TSH levels are while TSH-RH and TSH levels are decreased.decreased. You can also get You can also get hyperthyroidism from over-secreting hyperthyroidism from over-secreting thyroid tumors.thyroid tumors.

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Disorders of the thyroid-- hyperthyroidism

HypothalamusHypothalamus

PituitaryPituitary

ThyroidThyroid

TT33, T, T44

TRHTRH

TSHTSH

__

+

__

+

Abs

+

•Graves disease•Tumor (of the hypothalamus, pituitary, or thyroid)

Figure 76-8 Patient with exophthalmic hyperthyroidism. Note protrusion of the eyes

and retraction of the superior eyelids. The basal metabolic rate was +40. (Courtesy Dr.

Leonard Posey.)

Draw the disrupted pathways!

HypothyroidismHypothyroidism

This can be caused by This can be caused by Hashimoto’s thyroiditisHashimoto’s thyroiditis Iodine deficiencyIodine deficiency TumorTumor

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CretinismCretinism (diminished mental ability) (diminished mental ability)

This term describes babies whose This term describes babies whose MOTHER had the lack of iodine. Baby MOTHER had the lack of iodine. Baby now cannot get iodine, and the baby now cannot get iodine, and the baby will have reduced growth and will have reduced growth and intellectual ability. Once it is born intellectual ability. Once it is born and gets a healthy diet, it still won’t and gets a healthy diet, it still won’t go back to normal because TH is go back to normal because TH is necessary for proper myelination and necessary for proper myelination and synaptic formation. synaptic formation.

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Congenital HypothyroidismCongenital Hypothyroidism

Congenital hypothyroidismCongenital hypothyroidism is the is the term for a baby whose thyroid gland term for a baby whose thyroid gland is not working correctly (not is not working correctly (not secreting enough TH). The problem is secreting enough TH). The problem is only with baby, not with the mom. only with baby, not with the mom.

Congenital hypothyroidism and cretin Congenital hypothyroidism and cretin babies have similar symptoms. Child babies have similar symptoms. Child will stay tiny because GH does not will stay tiny because GH does not work without TH.work without TH.

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Hashimoto’s thyroiditisHashimoto’s thyroiditis Hashimoto’s thyroiditisHashimoto’s thyroiditis is an autoimmune disorder, is an autoimmune disorder,

where antibodies attack and destroy the thyroid gland, where antibodies attack and destroy the thyroid gland, and and TH goes down while TSH-RH and TSH are TH goes down while TSH-RH and TSH are elevated.elevated. The healthy remaining thyroid tissue will The healthy remaining thyroid tissue will enlarge.enlarge.

MyxedemaMyxedema is non-pitting edema. Touch it, feels solid, is non-pitting edema. Touch it, feels solid, and does not leave a fingerprint when you push on it. It and does not leave a fingerprint when you push on it. It is a common symptom in Hashimoto’s thyroiditis. A few is a common symptom in Hashimoto’s thyroiditis. A few people (4%) with Graves’ Disease get myxedema also.people (4%) with Graves’ Disease get myxedema also.

People with Hashimoto’s thyroiditis have depressed People with Hashimoto’s thyroiditis have depressed mental and emotional activity, may have psychosis, not mental and emotional activity, may have psychosis, not in touch with reality, detached. They gain weight easily, in touch with reality, detached. They gain weight easily, are tired and sleep a lot.are tired and sleep a lot.

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The Adrenal GlandsThe Adrenal Glands Located on the superior surface of the kidneysLocated on the superior surface of the kidneys

Two endocrine glands in one (different embryological origin)Two endocrine glands in one (different embryological origin)

– ADRENAL MEDULLA – a knot of sympathetic ADRENAL MEDULLA – a knot of sympathetic nervous tissuenervous tissue Secretes catecholamines (mostly epinephrine)Secretes catecholamines (mostly epinephrine)

– Active in “fight, flight, and fright” responseActive in “fight, flight, and fright” response

– ADRENAL CORTEX – bulk of the adrenal glandADRENAL CORTEX – bulk of the adrenal gland Secretes aldosterone Secretes aldosterone (salt and water balance for (salt and water balance for

blood pressure)blood pressure) Secretes androgens and estrogens Secretes androgens and estrogens (sex (sex

hormones)hormones) Secretes cortisol Secretes cortisol (anti-stress and anti-inflammation (anti-stress and anti-inflammation

hormone)hormone)

Adrenal MedullaAdrenal Medulla

The adrenal medulla releases The adrenal medulla releases catecholamines (epinephrine and catecholamines (epinephrine and norepinephrine)norepinephrine)..

These catecholamines are released when the sympathetic nervous system is These catecholamines are released when the sympathetic nervous system is activated (“fight or flight”).activated (“fight or flight”).

When you run from a predator, is that when you want insulin to take glucose from When you run from a predator, is that when you want insulin to take glucose from blood? No, you want to keep it there so the brain can get the glucose. The brain blood? No, you want to keep it there so the brain can get the glucose. The brain needs to think of a way to escape, and thinking burns glucose. needs to think of a way to escape, and thinking burns glucose.

Therefore, epinephrine is antagonistic to insulinTherefore, epinephrine is antagonistic to insulin Cells that don’t get the glucose during fight or flight break down fatty acids to get Cells that don’t get the glucose during fight or flight break down fatty acids to get

their ATP. These fatty acids will be taken to the liver for gluconeogenesis to their ATP. These fatty acids will be taken to the liver for gluconeogenesis to elevate the depleted blood glucose levels. Glycogen will also be broken down to elevate the depleted blood glucose levels. Glycogen will also be broken down to glucose to elevate the depleted blood glucose levels.glucose to elevate the depleted blood glucose levels.

Epinephrine has the same effect as the sympathetic nervous system:Epinephrine has the same effect as the sympathetic nervous system:– Heart rate and force increases. Heart rate and force increases. – Digestion slowsDigestion slows– respiratory passages open (bronchiole dilation)respiratory passages open (bronchiole dilation)– BP goes up (from vasoconstriction in less-needed organs). BP goes up (from vasoconstriction in less-needed organs).

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Adrenal CortexAdrenal Cortex Secretes a variety of hormones- Secretes a variety of hormones- all are steroids all are steroids

(steroids are made from cholesterol) and are grouped (steroids are made from cholesterol) and are grouped into three main categories:into three main categories:– Mineralocorticoids Mineralocorticoids

AldosteroneAldosterone -Sodium/water reabsorbed -Sodium/water reabsorbed– Androgens and EstrogensAndrogens and Estrogens

Male sex hormones (Androgens)Male sex hormones (Androgens) Female sex hormones (estrogen)Female sex hormones (estrogen)

– Glucocorticoids Glucocorticoids CortisolCortisol – secreted in response to ACTH from the – secreted in response to ACTH from the

pituitary gland. Cortisol stimulates fat and protein pituitary gland. Cortisol stimulates fat and protein catabolism to use for gluconeogenesis.catabolism to use for gluconeogenesis.

Adrenal Cortex HormonesAdrenal Cortex Hormones

AldosteroneAldosterone Testosterone and EstrogenTestosterone and Estrogen CortisolCortisol

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AldosteroneAldosteroneAldosterone Aldosterone (a mineralocorticoid) targets (a mineralocorticoid) targets the cells of kidney, increases the amount of the cells of kidney, increases the amount of salt and water that is reabsorbed, and that salt and water that is reabsorbed, and that increases blood volume, which elevates increases blood volume, which elevates blood pressure. blood pressure.

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How Low BP is RaisedHow Low BP is Raised When When baroreceptorsbaroreceptors detect low blood pressure, the detect low blood pressure, the

kidney releases an enzyme called kidney releases an enzyme called reninrenin, which cuts , which cuts Angiotensinogen into angiotensin-1 (A1), which Angiotensinogen into angiotensin-1 (A1), which travels through blood to the pulmonary capillary bed, travels through blood to the pulmonary capillary bed, where cells have angiotensin converting enzyme that where cells have angiotensin converting enzyme that cuts A1 into A2 (the active form). cuts A1 into A2 (the active form). – Any word that ends in –ogen means it is a longer, inactive Any word that ends in –ogen means it is a longer, inactive

protein, called a zymogen.protein, called a zymogen.– To become activated, they need to be cut by an enzyme into To become activated, they need to be cut by an enzyme into

a smaller segment. a smaller segment. These These high levels of A2 high levels of A2 stimulates the adrenal stimulates the adrenal

cortex to make more cortex to make more aldosteronealdosterone, and also , and also stimulates the hypothalamus to release stimulates the hypothalamus to release ADHADH. .

This will raise the blood pressure.This will raise the blood pressure.

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Prednisone, cortisone, cortisol, and aldosterone are all similar in structure. One can be used to make the others.If ACTH is

demanding more cortisol, but the body cannot make enough, it may start making androgens instead.

AndrogensAndrogens Androgens are called male sex hormones because they Androgens are called male sex hormones because they

cause male secondary sexual characteristics to develop, such cause male secondary sexual characteristics to develop, such as facial hair and low voice. as facial hair and low voice.

The main androgen secreted by the adrenal gland is called The main androgen secreted by the adrenal gland is called DHEA. DHEA.

DHEA can be converted into DHEA can be converted into testosterone or estrogentestosterone or estrogen.. A large amount of testosterone is made in the testes in A large amount of testosterone is made in the testes in

males.males. A small amount of testosterone is made in adrenal cortex in A small amount of testosterone is made in adrenal cortex in

males and females.males and females. If the adrenal cortex hyper-secretes testosterone and other If the adrenal cortex hyper-secretes testosterone and other

androgens, it won’t impact a male, because the testes make androgens, it won’t impact a male, because the testes make more than that already. more than that already.

However, in females, hypersecretion causes masculinization However, in females, hypersecretion causes masculinization (such as facial hair and low voice).(such as facial hair and low voice).

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EstrogenEstrogen Estrogens are one of the female sex hormones because Estrogens are one of the female sex hormones because

they cause female secondary sexual characteristics to they cause female secondary sexual characteristics to develop, such as breasts. develop, such as breasts.

A large amount of estrogen is made in the ovaries in A large amount of estrogen is made in the ovaries in females.females.

A small amount of estrogen is made in adrenal cortex in A small amount of estrogen is made in adrenal cortex in males and females.males and females.

The androgen, DHEA, can be converted into The androgen, DHEA, can be converted into estrogenestrogen.. If the adrenal cortex hypersecretes estrogen, it won’t If the adrenal cortex hypersecretes estrogen, it won’t

impact a female’s sex characteristics, because the ovaries impact a female’s sex characteristics, because the ovaries make more than that already. make more than that already.

However, in males, hypersecretion causes feminization However, in males, hypersecretion causes feminization (such as breast development).(such as breast development).

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Cortisol: Hormonal Cortisol: Hormonal MechanismMechanism

ACTH-RH is released by the hypothalamus.ACTH-RH is released by the hypothalamus. ACTH is released by pituitary.ACTH is released by pituitary. Cortisol (also called corticotropic hormone or CT). Cortisol (also called corticotropic hormone or CT). Cortisol affects almost all cells in body. Cortisol affects almost all cells in body.

Note: When ACTH plus cholesterol is present, you Note: When ACTH plus cholesterol is present, you can take cortisol and turn it into aldosterone if you can take cortisol and turn it into aldosterone if you need to.need to.– It does not do this unless the blood pressure is too low, It does not do this unless the blood pressure is too low,

because aldosterone is under a because aldosterone is under a humeralhumeral mechanism mechanism (turned on by high (turned on by high bloodblood levels of potassium or A2). levels of potassium or A2).

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Glucocorticoids (cortisol)Glucocorticoids (cortisol)

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Glucocorticoids (GC) are a class of steroid hormones Glucocorticoids (GC) are a class of steroid hormones that bind to the glucocorticoid receptor (GR), which is that bind to the glucocorticoid receptor (GR), which is present in almost every cell in the body. present in almost every cell in the body.

The name glucocorticoid (glucose + cortex + steroid) The name glucocorticoid (glucose + cortex + steroid) derives from their role in the regulation of the derives from their role in the regulation of the metabolism of glucose, their synthesis in the adrenal metabolism of glucose, their synthesis in the adrenal cortex, and their steroidal structure. They suppress the cortex, and their steroidal structure. They suppress the immune system (they are anti-inflammatory).immune system (they are anti-inflammatory).

Cortisol (also known as hydrocortisone) is one of the Cortisol (also known as hydrocortisone) is one of the most important glucocorticoids.most important glucocorticoids.

Others are prednisone, prednisolone, dexamethasone, Others are prednisone, prednisolone, dexamethasone, and triamcinolone, which are also commonly used and triamcinolone, which are also commonly used medicines for anti-inflammation. medicines for anti-inflammation.

Effects of Increased Effects of Increased GlucocorticoidsGlucocorticoids

Cortisol is called an anti-stress hormone because it does Cortisol is called an anti-stress hormone because it does several things: several things:

Stimulates Stimulates protein and fat catabolism (breakdown)protein and fat catabolism (breakdown)– The breakdown products are then taken to the liver for The breakdown products are then taken to the liver for

gluconeogenesis gluconeogenesis in the liverin the liver Inhibits glucose uptake by the body but not the brainInhibits glucose uptake by the body but not the brain It elevates blood glucose (diabetogenic effect)It elevates blood glucose (diabetogenic effect) It inhibits It inhibits non essential functions like non essential functions like reproduction and reproduction and

growthgrowth It suppresses the immune responseIt suppresses the immune response

– That means it is an That means it is an anti-inflammatory agentanti-inflammatory agent It is prescribed as a medicine to suppress inflammation and It is prescribed as a medicine to suppress inflammation and

the immune system. the immune system.

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CortisolCortisol Cortisol (also known as corticosterol and also Cortisol (also known as corticosterol and also

known as hydrocortisone)known as hydrocortisone) The hypothalamus releases ACTH-RH, pituitary The hypothalamus releases ACTH-RH, pituitary

releases ACTH, adrenal gland releases cortisol. The releases ACTH, adrenal gland releases cortisol. The adrenal gland also can release androgens.adrenal gland also can release androgens.

When there is an intense need to make cortisol When there is an intense need to make cortisol in response to stress, and if the body cannot in response to stress, and if the body cannot keep up with the demand for cortisol, excess keep up with the demand for cortisol, excess ACTH might be shunted into the androgen ACTH might be shunted into the androgen production pathway, so that androgens are production pathway, so that androgens are secreted instead of cortisol. Excess androgens secreted instead of cortisol. Excess androgens do not affect males, but females might develop do not affect males, but females might develop more masculine features.more masculine features.

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PrednisonePrednisone If a person has a lot of cortisol or prednisone in their If a person has a lot of cortisol or prednisone in their

body, blood sugar levels rise too much, and sugar body, blood sugar levels rise too much, and sugar spills out in the urine. They have symptoms of spills out in the urine. They have symptoms of diabetes, although that is not their disease. You have diabetes, although that is not their disease. You have some cortisol in you now to some cortisol in you now to help maintain normally help maintain normally elevated blood glucose levels between mealselevated blood glucose levels between meals, , and glucocorticoids and glucocorticoids stimulate smooth muscle in stimulate smooth muscle in the vasculature to maintain BPthe vasculature to maintain BP. .

In high doses only, prednisone may be given for In high doses only, prednisone may be given for asthma because it suppresses smooth muscle asthma because it suppresses smooth muscle from constrictingfrom constricting, and bronchioles cannot close up. , and bronchioles cannot close up. What would you predict their natural prednisone What would you predict their natural prednisone hormone levels to be, without the inhaler? highhormone levels to be, without the inhaler? high

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ADDISON’S DISEASEADDISON’S DISEASE Also called Also called Primary Adrenal InsufficiencyPrimary Adrenal Insufficiency and and

hypoadrenalism; mainly see effects in the hands, fingers, hypoadrenalism; mainly see effects in the hands, fingers, and gums. and gums.

Addison’s disease may be caused by anything that disturbs Addison’s disease may be caused by anything that disturbs the production of adrenal hormones (for some reason, the production of adrenal hormones (for some reason, Tuberculosis attacks the adrenal glands as well as the Tuberculosis attacks the adrenal glands as well as the lungs, and can cause hypoadrenalism). lungs, and can cause hypoadrenalism).

In Addison’s disease, the adrenal cortex does not respond In Addison’s disease, the adrenal cortex does not respond to pituitary orders. to pituitary orders. Cortisol levels are low, but pituitary Cortisol levels are low, but pituitary ACTH and hypothalamus ACTH-RH hormones are ACTH and hypothalamus ACTH-RH hormones are high. high.

Symptoms of Addison’s disease are decreased Symptoms of Addison’s disease are decreased glucose levels, a drop in blood pressure from water glucose levels, a drop in blood pressure from water and salt imbalance, and darkening of the skin.and salt imbalance, and darkening of the skin.

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CUSHING’S DISEASECUSHING’S DISEASE

Excess ACTH caused only by a Excess ACTH caused only by a pituitary pituitary tumortumor. Patient has . Patient has excess cortisol, high excess cortisol, high blood pressure, high blood glucoseblood pressure, high blood glucose, , and too much aldosterone is produced. and too much aldosterone is produced. More salt and water is reabsorbed by the More salt and water is reabsorbed by the kidney, so the blood volume increases. In kidney, so the blood volume increases. In this disorder, the this disorder, the hypothalamus (ACTH-hypothalamus (ACTH-RH) levels are low, the other hormone RH) levels are low, the other hormone levels (ACTH, cortisol, androgens, and levels (ACTH, cortisol, androgens, and aldosterone) are high.aldosterone) are high.

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Symptoms of Cushing’s Disease and Cushing’s Symptoms of Cushing’s Disease and Cushing’s SyndromeSyndrome

Fat deposition around waist, scapula (Fat deposition around waist, scapula (buffalo buffalo humphump), and “), and “moon” shaped facemoon” shaped face. There is . There is muscle lossmuscle loss and weakness (cortisol tells muscles and weakness (cortisol tells muscles to break down), thin skin with to break down), thin skin with striaestriae, (High levels of , (High levels of cortisol leads to destruction of collagen, get thin cortisol leads to destruction of collagen, get thin and striae on skin), and striae on skin), hyperglycemia, immune hyperglycemia, immune suppressionsuppression. Excessive amounts of adrenal . Excessive amounts of adrenal stimulation causes release of male steroids, causing stimulation causes release of male steroids, causing male secondary characteristics, but only in females. male secondary characteristics, but only in females. Adult onset disease in females causes Adult onset disease in females causes masculinizationmasculinization, including facial hair, thicker jaw , including facial hair, thicker jaw

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GROWTH HORMONE GROWTH HORMONE (SOMATOTROPIN)(SOMATOTROPIN)

GH needs TH to be present. GH stimulates all GH needs TH to be present. GH stimulates all cells to increase protein synthesis, fat utilization, cells to increase protein synthesis, fat utilization, and gluconeogenesis.and gluconeogenesis.

Gigantism Gigantism is the result of excess GH during pre-is the result of excess GH during pre-puberty and puberty and acromegalyacromegaly is the result of excess is the result of excess GH after growth plates closed. GH after growth plates closed.

The genetic determination of a person’s height The genetic determination of a person’s height has multiple genes involved, so parents might be has multiple genes involved, so parents might be tall and have smaller children. There are no rules tall and have smaller children. There are no rules to predict it. A child may also be small due to a to predict it. A child may also be small due to a defect in the placenta, blocking nutrients during defect in the placenta, blocking nutrients during development. development.

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PARATHYROID GLANDSPARATHYROID GLANDS There are several of these glands, embedded in There are several of these glands, embedded in

the thyroid gland on the posterior surface. the thyroid gland on the posterior surface. The parathyroid glands are the ones that are the The parathyroid glands are the ones that are the

most responsible for most responsible for maintaining blood maintaining blood calcium levels.calcium levels.

They accomplish this by releasing They accomplish this by releasing parathyroid parathyroid hormonehormone, which stimulates osteoclasts to chew , which stimulates osteoclasts to chew away bone, away bone, releasing the bone’s calcium into releasing the bone’s calcium into the bloodstreamthe bloodstream. .

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PARATHYROID GLANDSPARATHYROID GLANDS The antagonist of parathyroid hormone is The antagonist of parathyroid hormone is

calcitonin, calcitonin, which is produced in the thyroid which is produced in the thyroid gland, and stimulates osteoblasts to take calcium gland, and stimulates osteoblasts to take calcium from the blood and deposit it in bone. from the blood and deposit it in bone.

Parathyroid levels are released by a Parathyroid levels are released by a humeral humeral mechanism.mechanism.

If blood calcium levels are low, parathyroid If blood calcium levels are low, parathyroid hormone is released. hormone is released.

If blood calcium levels are high, parathyroid If blood calcium levels are high, parathyroid levels are low. levels are low.

NOTE: Parathyroid glands are do not actually NOTE: Parathyroid glands are do not actually metabolize (use up) calcium.metabolize (use up) calcium.

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PARATHYROID GLANDSPARATHYROID GLANDS

There are three ways that the There are three ways that the parathyroid gland raises blood parathyroid gland raises blood calcium levelscalcium levels

Stimulates osteoclasts to move bone Stimulates osteoclasts to move bone calcium into the bloodstreamcalcium into the bloodstream

Stimulates the intestines to absorb Stimulates the intestines to absorb more calcium from dietmore calcium from diet

Stimulates the kidneys to stop Stimulates the kidneys to stop excreting calciumexcreting calcium

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Other Endocrine GlandsOther Endocrine Glands Many of the glands we talked about have no other function Many of the glands we talked about have no other function

than to make hormones. But almost all organs are than to make hormones. But almost all organs are endocrine glands in addition to their other functions.endocrine glands in addition to their other functions.

HeartHeart pumps blood and produces hormones pumps blood and produces hormones GI tractGI tract digests food and produces hormones. digests food and produces hormones. Liver Liver makes enzymes, produces hormones, is involved in makes enzymes, produces hormones, is involved in

calcium metabolismcalcium metabolism Kidney: Kidney: excretes wastes, makes hormones, is involved in excretes wastes, makes hormones, is involved in

calcium metabolism and RBC productioncalcium metabolism and RBC production Dermis Dermis Involved in calcium metabolism, vitamin D Involved in calcium metabolism, vitamin D

synthesissynthesis– Epithelial glands that have ducts are NOT endocrine glandsEpithelial glands that have ducts are NOT endocrine glands

LungsLungs oxygenates and produces hormones. oxygenates and produces hormones. Bones Bones synthesize and secrete Vitamin D.synthesize and secrete Vitamin D. PlacentaPlacenta oxygenates and produces hormones. oxygenates and produces hormones. The only thing that does NOT make hormones are epithelial The only thing that does NOT make hormones are epithelial

glands that have ducts (hormone glands are by definition glands that have ducts (hormone glands are by definition without ducts).without ducts).