Sections 9.2, 9.3 & Sections 9.2, 9.3 & 9.49.4The Mammalian Circulatory The Mammalian Circulatory

System, The Mammalian Heart & System, The Mammalian Heart & HomeostasisHomeostasis

The HeartThe HeartSize of your fist.Hardest-working muscle in your body.Contains four chambers:

Left and right atria (receiving chambers).Left and right ventricles (delivery chambers).

Left and right sides of the heart are separated by a muscular septum.

Heart AnatomyHeart Anatomy The heart is composed of 4 chambersThe heart is composed of 4 chambers

2 atria: receives blood from veins2 atria: receives blood from veins 2 ventricles: pumps blood into arteries2 ventricles: pumps blood into arteries

The heart contains 4 valves (prevents The heart contains 4 valves (prevents backflow of blood)backflow of blood) 2 atrioventricular valves (AV valves)2 atrioventricular valves (AV valves)

The tricuspid valve (b/w right atrium and ventricle)The tricuspid valve (b/w right atrium and ventricle) The bicuspid valve (b/w left atrium and ventricle)The bicuspid valve (b/w left atrium and ventricle)

2 semi-lunar valves2 semi-lunar valves The aortic valve (b/w left ventricle and aorta)The aortic valve (b/w left ventricle and aorta) The pulmonary valve (b/w right ventricle and The pulmonary valve (b/w right ventricle and

pulmonary artery)pulmonary artery)

External heart anatomyExternal heart anatomy

Internal view of the heartInternal view of the heart

The Anatomy of the Heart - Learning Activity -

Pathways of Blood through the HeartPathways of Blood through the Heart Pulmonary CircuitPulmonary Circuit

Right side of heart.Right side of heart. Low-pressure system.Low-pressure system. Route of blood taken from the heart to the Route of blood taken from the heart to the

lungs and backlungs and back Systemic CircuitSystemic Circuit

Left side of heart.Left side of heart. High-pressure system.High-pressure system. Route of blood taken throughout the body to Route of blood taken throughout the body to

the limbs and other organsthe limbs and other organs Cardiac CirculationCardiac Circulation

Route of blood throughout the heart muscleRoute of blood throughout the heart muscleCardiovascular System

The Pulmonary CircuitThe Pulmonary Circuit The The pulmonary circuitpulmonary circuit begins with the begins with the

pulmonary trunkpulmonary trunk from the right from the right ventricle which branches into two ventricle which branches into two pulmonary arteriespulmonary arteries that take oxygen- that take oxygen-poor blood to the lungs. poor blood to the lungs.

In the lungs, oxygen diffuses into the In the lungs, oxygen diffuses into the blood, and carbon dioxide diffuses out blood, and carbon dioxide diffuses out of the blood to be expelled by the of the blood to be expelled by the lungs.lungs.

Four Four pulmonary veinspulmonary veins return oxygen- return oxygen-rich blood to the left atrium.rich blood to the left atrium.

http://www.kscience.co.uk/animations/heart.swf

Pulmonary CircuitPulmonary Circuit

The right atrium receives oxygen-poor blood The right atrium receives oxygen-poor blood from the:from the: Superior vena cava.Superior vena cava. Inferior vena cava.Inferior vena cava.

Blood enters the Blood enters the right atrium right atrium & flows through & flows through the the tricuspid valvetricuspid valve or the or the rightright atrioventricular atrioventricular valve (AV- valve (AV-valve).valve).

Pulmonary CircuitPulmonary Circuit The blood passes through the The blood passes through the pulmonary semi-pulmonary semi-

lunar valvelunar valve & enters the & enters the pulmonary trunkpulmonary trunk, , which divides into the which divides into the leftleft & & right pulmonary right pulmonary arteriesarteries..

The pulmonary arteries divide into capillaries The pulmonary arteries divide into capillaries where external gas exchange occurs.where external gas exchange occurs.

Oxygenated blood travels from the capillariesOxygenated blood travels from the capillaries

to the to the leftleft & & rightright pulmonary veinspulmonary veins, which, which

return the blood to the return the blood to the left atrium.left atrium.

The Systemic CircuitThe Systemic Circuit The The systemic circuitsystemic circuit starts with starts with

the aorta carrying Othe aorta carrying O22-rich blood -rich blood from the left ventricle. from the left ventricle.

The aorta branches with an artery The aorta branches with an artery going to each specific organ. going to each specific organ.

Generally, an artery divides into Generally, an artery divides into arterioles and capillaries which arterioles and capillaries which then lead to venules. then lead to venules.

The vein that takes blood to the vena The vein that takes blood to the vena cava often has the same name as the cava often has the same name as the artery that delivered blood to the artery that delivered blood to the organ.organ.

In the adult systemic circuit, arteries In the adult systemic circuit, arteries carry blood that is relatively high in carry blood that is relatively high in oxygen and relatively low in carbon oxygen and relatively low in carbon dioxide, and veins carry blood that is dioxide, and veins carry blood that is relatively low in oxygen and relatively relatively low in oxygen and relatively high in carbon dioxide. high in carbon dioxide.

This is the reverse of the pulmonary This is the reverse of the pulmonary circuit.circuit.

Systemic CircuitSystemic Circuit

Blood passes from the Blood passes from the left atriumleft atrium through through the the left AV-valveleft AV-valve or or bicuspid (mitral) valvebicuspid (mitral) valve to the to the left ventricle.left ventricle. Left ventricular walls are two times thicker Left ventricular walls are two times thicker

than in the right ventricle.than in the right ventricle. Blood travels through the Blood travels through the aortic aortic

semi-lunar valve semi-lunar valve to the to the aortaaorta..

Systemic CircuitSystemic Circuit

The aorta branches into smaller The aorta branches into smaller systemic arteriessystemic arteries, which branch into , which branch into arteriolesarterioles & then & then capillariescapillaries..

At the capillaries, internal gas exchange At the capillaries, internal gas exchange occurs with the body cells.occurs with the body cells.

Capillaries rejoin as Capillaries rejoin as venules venules & then as & then as veinsveins..

Deoxygenated blood returns to the right Deoxygenated blood returns to the right atrium via the superior & inferior vena atrium via the superior & inferior vena cava.cava.

Animation: Gas Exchange During Respiration

Major arteries and veins of Major arteries and veins of the systemic circuitthe systemic circuit

The Blood VesselsThe Blood Vessels

The The cardiovascular systemcardiovascular system has has three types of blood vessels:three types of blood vessels:

ArteriesArteries (and (and arteriolesarterioles) – carry ) – carry blood away from the heartblood away from the heart

CapillariesCapillaries – where nutrient and – where nutrient and gas exchange occur (distribution gas exchange occur (distribution pipes)pipes)

VeinsVeins (and (and venulesvenules) – carry blood ) – carry blood toward the heart, contain valves. toward the heart, contain valves.

Blood VesselsBlood Vessels Arteries: thick-walled blood vessels that Arteries: thick-walled blood vessels that

ALWAYS carry blood AWAY from the ALWAYS carry blood AWAY from the heart.heart.

Veins: thin-walled blood vessels that Veins: thin-walled blood vessels that ALWAYS carry blood TOWARD the heart.ALWAYS carry blood TOWARD the heart.

Arteries Arteries Arterioles Arterioles Capillaries Capillaries Venules Venules Veins Veins

Blood VesselsBlood Vessels

The ArteriesThe Arteries ArteriesArteries and arterioles take blood and arterioles take blood

away from the heart. away from the heart. The largest artery is the The largest artery is the aortaaorta. . The middle layer of an artery wall The middle layer of an artery wall

consists of consists of smooth musclesmooth muscle that can that can constrict to regulate blood flow and constrict to regulate blood flow and blood pressure. blood pressure.

ArteriolesArterioles (smaller branches of the (smaller branches of the arteries) can constrict or dilate, arteries) can constrict or dilate, changing blood pressure.changing blood pressure.

Blood Flow in ArteriesBlood Flow in Arteries Blood pressureBlood pressure due to the pumping of due to the pumping of

the heart accounts for the flow of the heart accounts for the flow of blood in the arteries. blood in the arteries.

Systolic pressureSystolic pressure is high when the is high when the heart expels the blood. heart expels the blood.

Diastolic pressureDiastolic pressure occurs when the occurs when the heart ventricles are relaxing. heart ventricles are relaxing.

Both pressures decrease with Both pressures decrease with distance from the left ventricle distance from the left ventricle because blood enters more and more because blood enters more and more arterioles and arteries.arterioles and arteries.

Arterial SystemArterial System Transports blood under pressure.Transports blood under pressure. When the heart empties, the blood moves in a When the heart empties, the blood moves in a

pulse-like wave throughout the circulatory pulse-like wave throughout the circulatory system.system.

Arterioles have a smaller diameter than Arterioles have a smaller diameter than arteries & are less elastic BUT the contraction arteries & are less elastic BUT the contraction & relaxation of arterioles is the major & relaxation of arterioles is the major determinant of the overall blood pressure.determinant of the overall blood pressure.

Arterial layers:Arterial layers: Inner layer of epithelial tissue (endothelium).Inner layer of epithelial tissue (endothelium). Middle layer of smooth muscle.Middle layer of smooth muscle. Outer layer of elastic connective tissue.Outer layer of elastic connective tissue.

The Aorta: connects the heart to the arteries The Aorta: connects the heart to the arteries that extend throughout the bodythat extend throughout the body

The CapillariesThe Capillaries CapillariesCapillaries have walls only one cell have walls only one cell

thick to allow exchange of gases and thick to allow exchange of gases and nutrients with tissue fluid. nutrients with tissue fluid.

Capillary beds are present in all Capillary beds are present in all regions of the body but not all regions of the body but not all capillary beds are open at the same capillary beds are open at the same time. time.

Contraction of a Contraction of a sphinctersphincter musclemuscle closes off a bed and blood can flow closes off a bed and blood can flow through an through an arteriovenous shuntarteriovenous shunt that that bypasses the capillary bed.bypasses the capillary bed.

Blood Flow in CapillariesBlood Flow in Capillaries Blood moves Blood moves

slowly in slowly in capillaries capillaries because there are because there are more capillaries more capillaries than arterioles. than arterioles.

This allows time This allows time for substances to for substances to be exchanged be exchanged between the between the blood and tissues.blood and tissues.

CapillariesCapillaries

Narrowest of all blood vessels.Narrowest of all blood vessels. RBCs travel in single file.RBCs travel in single file. Branching of the capillaries increases the Branching of the capillaries increases the

surface area available for diffusion.surface area available for diffusion. Connects the arterial & venous systems.Connects the arterial & venous systems.

Capillary ExchangeCapillary Exchange At the arteriole end of a capillary, At the arteriole end of a capillary,

water moves out of the blood due to water moves out of the blood due to the force of the force of blood pressureblood pressure. .

At the venule end, water moves into At the venule end, water moves into the blood due to the blood due to osmotic pressureosmotic pressure of of the blood.the blood.

Substances that leave the blood Substances that leave the blood contribute to contribute to tissue fluidtissue fluid, the fluid , the fluid between the body’s cells.between the body’s cells.

In the midsection of the capillary, In the midsection of the capillary, nutrients diffuse out and wastes nutrients diffuse out and wastes diffuse into the blood. diffuse into the blood.

Since plasma proteins are too large Since plasma proteins are too large to readily pass out of the capillary, to readily pass out of the capillary, tissue fluid tends to contain all tissue fluid tends to contain all components of plasma except it has components of plasma except it has lesser amounts of protein.lesser amounts of protein.

Excess tissue fluid is returned to the Excess tissue fluid is returned to the bloodblood stream as stream as lymphlymph in in lymphatic lymphatic vesselsvessels..

The VeinsThe Veins VenulesVenules drain blood from capillaries, drain blood from capillaries,

then join to form then join to form veinsveins that take that take blood to the heart. blood to the heart.

Veins have much less smooth muscle Veins have much less smooth muscle and connective tissue than arteries. and connective tissue than arteries.

Veins often have Veins often have valvesvalves that prevent that prevent the backward flow of blood when the backward flow of blood when closed.closed.

Veins carry about 70% of the body’s Veins carry about 70% of the body’s blood and act as a blood and act as a reservoirreservoir during during hemorrhagehemorrhage..

Blood Flow in VeinsBlood Flow in Veins

Venous blood flow is dependent Venous blood flow is dependent upon:upon:

1)1) skeletal muscle contraction, skeletal muscle contraction,

2)2) presence of valves in veins, and presence of valves in veins, and

3)3) respiratory movements. respiratory movements. Compression of veins causes blood to Compression of veins causes blood to

move forward past a valve that then move forward past a valve that then prevents it from returning backward. prevents it from returning backward.

Venous SystemVenous System Thinner walls, larger diameters & less muscle than Thinner walls, larger diameters & less muscle than

arteries.arteries. Contains 70% of total blood volume.Contains 70% of total blood volume. Most veins must work against gravity.Most veins must work against gravity.

Valves allow one-way flow of blood.Valves allow one-way flow of blood. Contraction of skeletal muscles pushes blood toward Contraction of skeletal muscles pushes blood toward

heart.heart. If veins are constantly stretched, they will lose their If veins are constantly stretched, they will lose their

elasticity & elasticity & varicose veinsvaricose veins will form. will form. Superior Vena CavaSuperior Vena Cava: returns deoxygenated blood : returns deoxygenated blood

to the heart from the upper half of the bodyto the heart from the upper half of the body Inferior Vena CavaInferior Vena Cava: returns deoxygenated blood : returns deoxygenated blood

to the heart from the lower half of the bodyto the heart from the lower half of the body

ArteriesArteries CapillariCapillarieses

VeinsVeins

Blood Blood directiondirection

From From HeartHeart

Joins Joins arteries arteries to veinsto veins

To heartTo heart

Muscle Muscle layerlayer

Thick Thick elasticelastic

NoneNone Thin elasticThin elastic

SemilunSemilunar valvesar valves

NoneNone NoneNone PresentPresent

PressurePressure High, with High, with pulsepulse

Less, no Less, no pulsepulse

Very low Very low with pulsewith pulse

Oxygen Oxygen concentrconcentra-tiona-tion

OxygenateOxygenatedd

Mixed (OMixed (O22 and COand CO22))

DeoxygenatedDeoxygenated

Differences between arteries Differences between arteries and veinsand veins

Arteries are vessels that are very muscular and Arteries are vessels that are very muscular and elasticelastic

Veins contain connective tissue and muscle, but Veins contain connective tissue and muscle, but veins are much less elastic and tend to have veins are much less elastic and tend to have larger internal diameters.larger internal diameters.

Pressure in veins < pressure in arteriesPressure in veins < pressure in arteries Veins contain one-way valves that keep blood Veins contain one-way valves that keep blood

flowing in one direction. These valves open flowing in one direction. These valves open under the pressure of blood going toward the under the pressure of blood going toward the heart, and close when it begins to go backward.heart, and close when it begins to go backward.

The walls of varicose veins are weak and allow The walls of varicose veins are weak and allow blood to collect and distend them so that the blood to collect and distend them so that the edges of the valve flaps cannot meet; blood may edges of the valve flaps cannot meet; blood may then move backwards and circulation is then move backwards and circulation is impaired.impaired.

Blood VesselsBlood Vessels

Passage of Blood Through the Passage of Blood Through the HeartHeart

Blood follows this sequence through the Blood follows this sequence through the heart: superior and inferior vena cava heart: superior and inferior vena cava →→ right atrium right atrium → tricuspid valve →→ tricuspid valve → right right ventricle ventricle → pulmonary semilunar valve →→ pulmonary semilunar valve → pulmonary trunk and arteries to the lungs pulmonary trunk and arteries to the lungs →→ pulmonary veins leaving the lungs pulmonary veins leaving the lungs →→ left left atrium atrium → bicuspid valve →→ bicuspid valve → left ventricle left ventricle → → aortic semilunar valve →aortic semilunar valve → aorta aorta → to the → to the bodybody. .

N.B.N.B. The pulmonary artery is the only artery The pulmonary artery is the only artery in the body that carries deoxygenated blood.in the body that carries deoxygenated blood. The Pulmonary vein is the only vein that carries The Pulmonary vein is the only vein that carries

oxygenated blood.oxygenated blood. http://www.bishopstopford.com/faculties/science/arthur/Heart%20drag&drop.swf

The pumping of the heart sends out The pumping of the heart sends out blood under pressure to the arteries.blood under pressure to the arteries.

Blood pressureBlood pressure is greatest in the is greatest in the aorta; the wall of the left ventricle is aorta; the wall of the left ventricle is thicker than that of the right ventricle thicker than that of the right ventricle and pumps blood to the entire body.and pumps blood to the entire body.

Blood pressure then decreases as the Blood pressure then decreases as the cross-sectional area of arteries and cross-sectional area of arteries and then arterioles increases.then arterioles increases.

Path of blood through the Path of blood through the heartheart

Blood Flow through the Human Heart

Blood circulation

Coronary CirculationCoronary Circulation Delivers oxygenated blood directly to the heart Delivers oxygenated blood directly to the heart

muscle.muscle. Consists of the Consists of the leftleft & & right coronary artery right coronary artery..MedMovie

Media Player

Coronary CirculationCoronary Circulation Coronary artery diseaseCoronary artery disease prevents the heart prevents the heart

from receiving enough oxygen.from receiving enough oxygen. After a heart attack the affected myocardium is After a heart attack the affected myocardium is

damaged & is permanently scarred.damaged & is permanently scarred. The functional The functional

myocardium will myocardium will compensate for the compensate for the damaged muscle. damaged muscle.

Compromised Coronary CirculationCompromised Coronary Circulation

Cardiovascular system Cardiovascular system diagramdiagram

Anatomy of the Heart Animation Sample

An Overview of Pulmonary and Systemic Circulati

The Heart CycleThe Heart Cycle

The heart of a healthy individual beats 75 The heart of a healthy individual beats 75 times per minute. The 2 sides of the heart times per minute. The 2 sides of the heart beat in unison, 1beat in unison, 1stst the 2 atria contract, the 2 atria contract, then the 2 ventricles.then the 2 ventricles.

The cardiac cycle is a continuous cycle of The cardiac cycle is a continuous cycle of relaxation & contraction.relaxation & contraction. DiastoleDiastole

Heart relaxation Heart relaxation SystoleSystole

Heart contraction (venticles contract)Heart contraction (venticles contract)

The HeartbeatThe Heartbeat

Each heartbeat is called a Each heartbeat is called a cardiac cyclecardiac cycle.. When the heart beats, the two atria When the heart beats, the two atria

contract together, then the two contract together, then the two ventricles contract; then the whole ventricles contract; then the whole heart relaxes.heart relaxes.

SystoleSystole is the contraction of heart is the contraction of heart chambers; chambers; diastolediastole is their relaxation. is their relaxation.

The The heart soundsheart sounds, lub-dub, are due to , lub-dub, are due to the closing of the atrioventricular the closing of the atrioventricular valves, followed by the closing of the valves, followed by the closing of the semilunar valves.semilunar valves.

DiastoleDiastole Blood enters all four Blood enters all four

chambers.chambers. Enters left atrium from Enters left atrium from

pulmonary veins.pulmonary veins. Enters right atrium from Enters right atrium from

inferior & superior vena cava.inferior & superior vena cava. Tricuspid & bicuspid valves Tricuspid & bicuspid valves

open, allowing blood to flow open, allowing blood to flow into the left & right ventricles.into the left & right ventricles.

Pulmonary & aortic semi-Pulmonary & aortic semi-lunar valves close due to a lunar valves close due to a decrease in ventricular decrease in ventricular pressure.pressure.

Blood pressure is reduced (80 Blood pressure is reduced (80 mm Hg).mm Hg).

SystoleSystole Aria contract to further fill Aria contract to further fill

the ventricles.the ventricles. Ventricles contract to force Ventricles contract to force

blood from the heart.blood from the heart. Blood leaves the right Blood leaves the right

ventricle through the open ventricle through the open pulmonary semi-lunar valve pulmonary semi-lunar valve into the pulmonary trunk & into the pulmonary trunk & pulmonary arteries.pulmonary arteries.

Blood leaves the left ventricle Blood leaves the left ventricle through the open aortic semi-through the open aortic semi-lunar valve into the aorta.lunar valve into the aorta.

Tricuspid & bicuspid valves Tricuspid & bicuspid valves forced closed due to an forced closed due to an increase in ventricular increase in ventricular pressure.pressure.

Blood pressure is increased Blood pressure is increased (120 mm Hg).(120 mm Hg).Animation: The

Cardiac Cycle (Quiz 1)

Heart Valves and Heart SoundsHeart Valves and Heart Sounds

Heart valves open & close at different Heart valves open & close at different times to ensure blood flows in the proper times to ensure blood flows in the proper direction.direction.

The “lub-dub” sound that you hear when The “lub-dub” sound that you hear when you use a stethoscope to listen to the you use a stethoscope to listen to the heart is caused by the closing of different heart is caused by the closing of different pairs of valves.pairs of valves.

““Lub”: Lub”: tricuspid & bicuspid valves close tricuspid & bicuspid valves close (beginning of systole).(beginning of systole).

““Dub”Dub”: pulmonary and aortic semi-lunar : pulmonary and aortic semi-lunar valves close (end of systole).valves close (end of systole).

Heart Valves and Heart SoundsHeart Valves and Heart Sounds

chmc_valves

http://www.wellesley.edu/Biology/Courses/111/HeartValves.MOV

Extrinsic Control of HeartbeatExtrinsic Control of Heartbeat A A cardiac control centercardiac control center in the in the medulla medulla

oblongataoblongata speeds up or slows down the speeds up or slows down the heart rate by way of the autonomic heart rate by way of the autonomic nervous system branches: nervous system branches: parasympathetic system – vagus nerveparasympathetic system – vagus nerve (slows heart rate) and the (slows heart rate) and the sympathetic sympathetic system – spinal cordsystem – spinal cord (increases heart (increases heart rate). rate).

Hormones Hormones epinephrineepinephrine and and norepinephrinenorepinephrine from the adrenal from the adrenal medulla also stimulate faster heart rate.medulla also stimulate faster heart rate.

Intrinsic Control of HeartbeatIntrinsic Control of Heartbeat The The SASA ((sinoatrialsinoatrial) ) nodenode, or , or pacemakerpacemaker, ,

initiates the heartbeat and causes the initiates the heartbeat and causes the atria to contract on average every 0.85 atria to contract on average every 0.85 seconds. seconds.

The The AVAV ( (atrioventricularatrioventricular) ) nodenode conveys conveys the stimulus and initiates contraction of the stimulus and initiates contraction of the ventricles. the ventricles.

The signal for the ventricles to contract The signal for the ventricles to contract travels from the AV node through travels from the AV node through specialized fibers called thespecialized fibers called the Bundle of HisBundle of His which eventually stimulate the smaller which eventually stimulate the smaller Purkinje fibersPurkinje fibers causes the ventricles causes the ventricles to contractto contractchmc_00_electricbeat

Cardiac Contractions and Cardiac Contractions and conductionconduction

The heart and circulation. Animated heart structure.

Chris Becker

Animation: Conducting System of the Heart

Blood PressureBlood Pressure

The pressure exerted on the arterial The pressure exerted on the arterial walls.walls.

The elastic property of vessels The elastic property of vessels allows for continuous blood flow allows for continuous blood flow throughout the circulatory system.throughout the circulatory system.

The difference between your systolic The difference between your systolic pressure & your diastolic pressure is pressure & your diastolic pressure is called your called your pulse pressure.pulse pressure.

Blood PressureBlood Pressure Blood pressure is Blood pressure is

highest in the aorta.highest in the aorta. Blood pressure & Blood pressure &

velocity both decline as velocity both decline as blood enters the blood enters the arterioles.arterioles.

The drop in pressure The drop in pressure results from the results from the resistance (friction) to resistance (friction) to blood flow.blood flow.

Low blood pressure Low blood pressure reduces your capacity to reduces your capacity to transport blood.transport blood.

High blood pressure can High blood pressure can weaken & rupture your weaken & rupture your arterial walls.arterial walls.http://132.241.10.14/bp/bp.swf

How does heart rate How does heart rate change?change? Heart rate increases as impulses from the Heart rate increases as impulses from the

vagus nerve (inhibitory nerves) decrease.vagus nerve (inhibitory nerves) decrease. Heart rate decreases as impulses from the Heart rate decreases as impulses from the

vagus nerve increasevagus nerve increase When large volumes of blood are passing When large volumes of blood are passing

through the vena cava, a message is sent to the through the vena cava, a message is sent to the heart rate centre to increase heart rateheart rate centre to increase heart rate

When large volumes of blood pass through the When large volumes of blood pass through the carotid artery and aorta, an impulse is sent to carotid artery and aorta, an impulse is sent to the heart rate centre to decrease heart ratethe heart rate centre to decrease heart rate

Temperature: high body temp increases Temperature: high body temp increases heart rateheart rate

Acidity: increase COAcidity: increase CO22 levels in the blood will levels in the blood will increase heart rateincrease heart rate

Hormones: adrenaline, thyroxin, insulin and Hormones: adrenaline, thyroxin, insulin and sex hormones all affect heart ratesex hormones all affect heart rate

Cardiac Output and FitnessCardiac Output and Fitness Cardiac outputCardiac output

A measure of the volume of blood pumped from each A measure of the volume of blood pumped from each ventricle per unit of timeventricle per unit of time

Heart rate and stroke volume affect cardiac outputHeart rate and stroke volume affect cardiac output Cardiac output = stroke volume x heart rateCardiac output = stroke volume x heart rate

Stroke volumeStroke volume The amount of blood forced out of the heart with each The amount of blood forced out of the heart with each

heartbeatheartbeat This is dependent on 2 factors:This is dependent on 2 factors:

How easily the heart fills with blood: depends on How easily the heart fills with blood: depends on the stretchiness of the ventriclesthe stretchiness of the ventricles

How readily the heart empties again: depends on How readily the heart empties again: depends on the strength of the ventricular contraction and the the strength of the ventricular contraction and the pressure exerted by the artery wallspressure exerted by the artery walls

Regular cardiovascular exercise will increase the Regular cardiovascular exercise will increase the resting stroke volume of your heart by enlarging resting stroke volume of your heart by enlarging the ventricular chambers, increasing distensibility the ventricular chambers, increasing distensibility and strengthening ventricular wallsand strengthening ventricular walls

Heart DefectsHeart Defects A A septal defectseptal defect is a hole in the is a hole in the

septum, the wall that separates the septum, the wall that separates the right and left ventricles. This defect right and left ventricles. This defect allows oxygenated and deoxygenated allows oxygenated and deoxygenated blood to mix in the heart.blood to mix in the heart.

Heart murmursHeart murmurs occur when one or occur when one or more of the heart valves does not open more of the heart valves does not open or close properly. This defect is called or close properly. This defect is called a murmur from the characteristic a murmur from the characteristic whooshing or rasping sound caused by whooshing or rasping sound caused by the blood escaping from the valve.the blood escaping from the valve.

Blood: The Transport MediumBlood: The Transport Medium Transport nutrient molecules from digestive tract Transport nutrient molecules from digestive tract

to cellsto cells Transport of oxygen from lungsTransport of oxygen from lungs Transport of wastes from respiration and other Transport of wastes from respiration and other

body reactionsbody reactions Clotting to prevent excessive blood lossClotting to prevent excessive blood loss

The Composition of Blood

The Plasma (Fluid) The Plasma (Fluid) makes up 55% of the makes up 55% of the blood volume.blood volume.

The Solids (Cells) The Solids (Cells) make up 45% of the make up 45% of the blood volume.blood volume. 0

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Blood Composition

Plasma Solids

Blood cell formation in red Blood cell formation in red bone marrowbone marrow

Composition of bloodComposition of blood

White Blood Cells - Learning Activity - Flash Player Installation

Blood SolidsBlood Solids

Red Blood CellsRed Blood Cells -Carry oxygen-Carry oxygen -Contain Hemoglobin-Contain Hemoglobin White Blood CellsWhite Blood Cells -Attack bacteria & other -Attack bacteria & other invadersinvaders PlateletsPlatelets -Control the blood clotting-Control the blood clotting processprocess

The Red Blood CellsThe Red Blood Cells Red blood cellsRed blood cells ((erythrocytes erythrocytes oror

RBCsRBCs) are made in the ) are made in the red bone red bone marrowmarrow of the skull, ribs, vertebrae, of the skull, ribs, vertebrae, and the ends of long bones.and the ends of long bones.

Normally there are 4 to 6 million Normally there are 4 to 6 million RBCs per mmRBCs per mm33 of whole blood. of whole blood.

Red blood cells contain the pigment Red blood cells contain the pigment hemoglobinhemoglobin for oxygen transport; for oxygen transport; hemogobin contains hemogobin contains hemeheme, a complex , a complex iron-containing group that transports iron-containing group that transports oxygen in the blood. oxygen in the blood.

Physiology of red blood Physiology of red blood cellscells

The air pollutant The air pollutant carbon carbon monoxidemonoxide combines more readily combines more readily with hemoglobin than does with hemoglobin than does oxygen, resulting in oxygen oxygen, resulting in oxygen deprivation and possible death.deprivation and possible death.

Red blood cells lack a nucleus Red blood cells lack a nucleus and have a 120 day life span. and have a 120 day life span.

When worn out, the red blood When worn out, the red blood cells are dismantled in the liver cells are dismantled in the liver and spleen. and spleen.

Iron is reused by the red bone marrow Iron is reused by the red bone marrow where stem cells continually produce where stem cells continually produce more red blood cells; the remainder of more red blood cells; the remainder of the heme portion undergoes chemical the heme portion undergoes chemical degradation and is excreted as bile degradation and is excreted as bile pigments into the bile. pigments into the bile.

Lack of enough hemoglobin results in Lack of enough hemoglobin results in anemiaanemia. .

The kidneys produce the hormone The kidneys produce the hormone erythropoietinerythropoietin to increase blood cell to increase blood cell production when oxygen levels are low.production when oxygen levels are low.

Disorder: AnemiaDisorder: Anemia Anemia occurs when there is a Anemia occurs when there is a

decreased number of RBCs, the RBCs decreased number of RBCs, the RBCs are deformed, or insufficient iron (due are deformed, or insufficient iron (due to missing heme groups)to missing heme groups)

Symptoms: tired, lack of energy, get ill Symptoms: tired, lack of energy, get ill easilyeasily

Rationale: low # of healthy RBCs Rationale: low # of healthy RBCs means less hemoglobin and insufficient means less hemoglobin and insufficient iron means less oxygen binding sitesiron means less oxygen binding sites

Treatment: increase the amount of iron Treatment: increase the amount of iron in your dietin your diet

The White Blood CellsThe White Blood Cells White blood cellsWhite blood cells ( (leukocytesleukocytes) have ) have

nuclei, are fewer in number than nuclei, are fewer in number than RBCs, with 5,000 – 10,000 cells per RBCs, with 5,000 – 10,000 cells per mmmm33, and defend against disease. , and defend against disease.

Two main types of WBCs: Two main types of WBCs: macrophagesmacrophages and and lymphocyteslymphocytes

Macrophages Macrophages (phagocytic cells) pass (phagocytic cells) pass through the walls of the capillaries to through the walls of the capillaries to engulf and digest pathogens.engulf and digest pathogens.

Macrophage engulfing bacteriaMacrophage engulfing bacteria

Disorder: LeukemiaDisorder: Leukemia

Leukemia is a cancerous disease where Leukemia is a cancerous disease where there is an increased number of immature there is an increased number of immature WBCs produced and a decrease in the WBCs produced and a decrease in the number of RBCs.number of RBCs.

Symptoms: increased risk of illness to Symptoms: increased risk of illness to infection, fatigue and low energyinfection, fatigue and low energy

Rationale: an increase in defective WBCs Rationale: an increase in defective WBCs due to radition, toxins… means that the due to radition, toxins… means that the WBCs are incapable of fighting infectionWBCs are incapable of fighting infection

Treatment: drug therapyTreatment: drug therapy

The Platelets and Blood The Platelets and Blood ClottingClotting

Platelets play an important role in Platelets play an important role in blood clotting and therefore help to blood clotting and therefore help to protect the body from excessive blood protect the body from excessive blood loss after injury.loss after injury.

Red bone marrow produces large cells Red bone marrow produces large cells called called megakaryocytesmegakaryocytes that fragment that fragment into into plateletsplatelets at a rate of 200 billion at a rate of 200 billion per day; blood contains 150,000–per day; blood contains 150,000–300,000 platelets per mm300,000 platelets per mm33. .

Twelve Twelve clotting factorsclotting factors in the blood in the blood help platelets form blood clots.help platelets form blood clots.

Human Blood GroupsHuman Blood Groups Blood type is determined by the presence or Blood type is determined by the presence or

absence of a protein, called an antigen on the absence of a protein, called an antigen on the surface of our RBCs.surface of our RBCs.

Antigen: a foreign macromolecule that does not Antigen: a foreign macromolecule that does not belong to the host organism and that induces an belong to the host organism and that induces an immune responseimmune response

Antibody: a protein that binds an antigen, Antibody: a protein that binds an antigen, produced by B cells, works to get rid of the produced by B cells, works to get rid of the antigenantigen

Blood Types, Antibodies and Blood Types, Antibodies and AntigensAntigens

Blood TypeBlood Type AntigenAntigen AntibodiesAntibodies

AA Protein AProtein A Anti-BAnti-B

BB Protein BProtein B Anti-AAnti-A

ABAB Protein A & BProtein A & B NoneNone

O O NoneNone Anti-A & Anti-Anti-A & Anti-BB

Blood Transfusions:•The antigen types of the recipient blood and the donor blood must be known.•In emergencies, type O is the universal donor since they do not have any antigens•Type AB is the universal recipient since they have no antibodies.•A second factor that affects the compatibility of human blood is the Rhesus factor, another protein marker.

Rhesus FactorRhesus Factor People who carry the protein are Rh-positive, People who carry the protein are Rh-positive,

while people without the protein are Rh-while people without the protein are Rh-negativenegative

Anti-Rh antibody is manufactured in the body Anti-Rh antibody is manufactured in the body only after an exposure to the Rh protein only after an exposure to the Rh protein markermarker

Therefore, a transfusion of Rh-positive blood Therefore, a transfusion of Rh-positive blood into an Rh-negative person is usually safe, into an Rh-negative person is usually safe, since the anti-Rh antibodies develop 2-4 since the anti-Rh antibodies develop 2-4 months after the transfusion. A second months after the transfusion. A second transfusion of Rh-positive blood will cause transfusion of Rh-positive blood will cause agglutination of the blood since the patient has agglutination of the blood since the patient has now developed Anti-Rh antibodies.now developed Anti-Rh antibodies.

Cardiovascular DisordersCardiovascular Disorders

Cardiovascular diseaseCardiovascular disease ( (CVDCVD) is the ) is the leading cause of death in Western leading cause of death in Western countries.countries.

Modern research efforts have improved Modern research efforts have improved diagnosis, treatment, and prevention.diagnosis, treatment, and prevention.

Major cardiovascular disorders include Major cardiovascular disorders include atherosclerosis, stroke, heart attack, atherosclerosis, stroke, heart attack, aneurysm, and hypertension.aneurysm, and hypertension.

AtherosclerosisAtherosclerosis AtherosclerosisAtherosclerosis is due to is due to

a build-up of fatty a build-up of fatty material (material (plaqueplaque), ), mainly cholesterol, mainly cholesterol, under the inner lining of under the inner lining of arteries. arteries.

The plaque can cause a The plaque can cause a thrombusthrombus (blood clot) to (blood clot) to form.form.

The thrombus can The thrombus can dislodge as an dislodge as an embolusembolus and lead to and lead to thromboembolismthromboembolism..

Atherosclerosis Calcification

Stroke, Heart Attack, and Stroke, Heart Attack, and AneurysmAneurysm

A A cerebrovascular accidentcerebrovascular accident, or , or strokestroke, results when an embolus , results when an embolus lodges in a cerebral blood vessel or a lodges in a cerebral blood vessel or a cerebral blood vessel bursts; a cerebral blood vessel bursts; a portion of the brain dies due to lack portion of the brain dies due to lack of oxygen. of oxygen.

A A myocardial infarctionmyocardial infarction, or , or heart heart attackattack, occurs when a portion of , occurs when a portion of heart muscle dies due to lack of heart muscle dies due to lack of oxygen.oxygen.

Partial blockage of a coronary artery Partial blockage of a coronary artery causes causes angina pectorisangina pectoris, or chest pain. , or chest pain.

An An aneurysmaneurysm is a ballooning of a is a ballooning of a blood vessel, usually in the abdominal blood vessel, usually in the abdominal aorta or arteries leading to the brain.aorta or arteries leading to the brain.

Death results if the aneurysm is in a Death results if the aneurysm is in a large vessel and the vessel bursts.large vessel and the vessel bursts.

Atherosclerosis and hypertension Atherosclerosis and hypertension weaken blood vessels over time, weaken blood vessels over time, increasing the risk of aneurysm.increasing the risk of aneurysm.

Coronary Bypass Coronary Bypass OperationsOperations

A A coronary bypass operationcoronary bypass operation involves removing a segment of involves removing a segment of another blood vessel and replacing another blood vessel and replacing a clogged coronary artery. a clogged coronary artery.

It may be possible to replace this It may be possible to replace this surgery with surgery with gene therapygene therapy that that stimulates new blood vessels to stimulates new blood vessels to grow where the heart needs more grow where the heart needs more blood flow. blood flow.

Coronary bypass operationCoronary bypass operation

Clearing Clogged ArteriesClearing Clogged Arteries

AngioplastyAngioplasty uses a long tube threaded uses a long tube threaded through an arm or leg vessel to the through an arm or leg vessel to the point where the coronary artery is point where the coronary artery is blocked; inflating the tube forces the blocked; inflating the tube forces the vessel open. vessel open.

Small metal Small metal stentsstents are expanded are expanded inside the artery to keep it open.inside the artery to keep it open.

Stents are coated with Stents are coated with heparinheparin to to prevent blood clotting and with prevent blood clotting and with chemicals to prevent arterial closing.chemicals to prevent arterial closing.

AngioplastyAngioplasty Habits of the Heart

Heart Transplants and Heart Transplants and Artificial HeartsArtificial Hearts

Heart transplantsHeart transplants are routinely are routinely performed but immunosuppressive performed but immunosuppressive drugs must be taken thereafter. drugs must be taken thereafter.

There is a shortage of human organ There is a shortage of human organ donors. donors.

Work is currently underway to Work is currently underway to improve self-contained improve self-contained artificial artificial heartshearts, and muscle cell transplants , and muscle cell transplants may someday be usefulmay someday be useful..

HypertensionHypertension About 20% of Americans suffer from About 20% of Americans suffer from

hypertensionhypertension ( (high blood pressurehigh blood pressure).). Hypertension is present when systolic Hypertension is present when systolic

pressure is 140 or greater or diastolic pressure is 140 or greater or diastolic pressure is 100 or greater; diastolic pressure is 100 or greater; diastolic pressure is emphasized when medical pressure is emphasized when medical treatment is considered.treatment is considered.

A genetic predisposition for A genetic predisposition for hypertension occurs in those who have a hypertension occurs in those who have a gene that codes for gene that codes for angiotensinogenangiotensinogen, a , a powerful vasoconstrictor.powerful vasoconstrictor.