the cardiovascular system: blood. list the components and functions of blood components. list the...
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CHAPTER 14THE CARDIOVASCULAR SYSTEM: BLOOD
List the components and functions of blood components.
List the components and functions of blood plasma.
Describe the various mechanisms that prevent blood loss.
Understand blood typing and transfusions.
OBJECTIVES
TRANSPORTATION◦ Oxygen
From lungs to cells◦ Carbon Dioxide
Waste product of cellular respiration◦ Nutrients
From gastrointestinal tract to body cells◦ Heat and Waste
Away from cells◦ Hormones
From endocrine glands to other body cells
FUNCTIONS OF BLOOD
REGULATION◦ pH
Of body fluids◦ Body temperature
Heat-absorbing and coolant properties of water in blood plasma
Flow of water through skin for cooling◦ Water content of cells
Through blood osmotic pressure
FUNCTIONS OF BLOOD
PROTECTION◦ Prevents blood loss through clotting◦ Combats microbes and toxins through action of
certain phagocytic white blood cells or specialized plasma proteins
◦ Interferon and complements are proteins that help protect against disease
FUNCTIONS OF BLOOD
Viscosity (stickiness or thickness; resistance to flow) ◦ greater than that of water
Temperature range 38C or 100.4F. pH range between 7.35 and 7.45
◦ Is this alkaline or acidic? 8% of total body weight.
Volume in average-sized adult male body ◦ 5 to 6 liters or 1.5 gallons.
Volume in average-sized adult female body◦ 4 to 5 liters or 1.2 gallons.
COMPONENTS OF WHOLE BLOOD
Whole blood composed of two portions◦ 55% blood plasma
Liquid containing dissolved substances◦ 45% formed elements
Cells and cell fragments
Hematocrit: percentage of total blood volume occupied by red blood cells (99% of formed elements are red blood cells)
Buffy coat: thin layer of platelets and pale colorless white blood cells; less than 1% of blood volume
COMPONENTS OF WHOLE BLOOD
Straw-colored liquid left when formed elements removed from blood blood plasma
Composition:◦ 91.5 % water◦ 7% proteins◦ 1.5% solutes
Principle solutes include:◦ Proteins (Albumins, Globulins, and Fibrinogen)◦ Nutrients ◦ Hormones ◦ Respiratory gases◦ Electrolytes◦ Waste products
Blood Plasma
Red Blood Cells (RBCs) White Blood Cells (WBCs)
◦ Granular leukocytes Neutrophils Eosinophils Basophils
◦ Agranular leukocytes T and B lymphocytes and natural killer cells Monocytes
Platelets
Formed Elements
Hemopoiesis: process through which formed elements develop from pluripotent stem cells in red bone marrow
Before birth hemopoiesis occurs in yolk sac of an
embryo Fetal hemopoiesis occurs in the liver, spleen,
thymus, and lymph nodes Hemopoiesis during the last three months before
birth occurs in red bone marrow and continues there throughout life
Formation of Blood Cells
Red bone marrow is derived from mesenchymal cells called pluripotent stem cells
Hormones stimulate pluripotent stem cells into two other types of stem cells:◦ Myeloid stem cells
Differentiate into red blood cells, platelets, eosinophils, basophils, neutrophils, and monocytes
◦ Lymphoid stem cells Differentiate into T and B lymphocytes
Formation of Blood Cells
Aka: ERYTHROCYTES
Hemoglobin oxygen-carrying pigment◦ Gives whole blood its red color
STRUCTURE OF RBCs:◦ Biconcave discs◦ 7-8µm in diameter (1µm = 1/25,000 of an inch)◦ No nuclei or other organelles◦ Cannot divide ◦ Do no carry on any extensive metabolic activity
Composed of : ◦ Selectively permeable plasma membrane◦ Cytosol◦ Hemoglobin
Healthy male has about 5.4 million RBCs/µL of blood Healthy female has about 4.8 million RBCs/µL of blood
Red Blood Cells(RBCs)
Live about 120 days◦ Wear and tear on plasma membrane squeezing
through capillaries necessitates replacement…
RBC LIFE CYCLE
(1) Macrophages in spleen, liver, and red bone marrow through the process of phagocytosis rupture worn-out red blood cells splitting apart the globin and heme portions of hemoglobin.
(2) Globin broken down into amino acids (to be used in protein synthesis).(3) Iron removed from heme portion associates with plasma protein called
transferrrin.(4) Iron-transferrin complex goes to red bone marrow for RBC precursor cells
to use in hemoglobin synthesis. IRON NEEDED FOR HEME PORTION OF HEMOGLOBIN, AMINO ACID NEEDED FOR GLOBIN.
◦ Also needed: Vitamin B12_ and Intrinsic factor. Intrinsic Factor protein produced in stomach lining
(5) Erythropoiesis is the process in red bone marrow that results in production of new red blood cells.
(6) Iron removed from heme, non-iron portion converted to hiliverdin, a green pigment, and then into bilirubin, a yellow-orange pigment. Bilirubin enters blood and is transported to the liver, where it is secreted into bile. Bile goes to small intestine then large intestine.(7) Bacteria in large intestine converts bilirubin into urobilinogen, which is absorbed back into the blood, and converted to a yellow pigment called urobilin, which is excreted in urine. Urobilinogen is eliminated in feces in the form of a brown pigment called stercobilin.
Erythropoiesis formation of only RBCs in the red bone marrow of adults
RBC PRODUCTION
Hypoxia DEFICIENCY OF OXYGEN
RBC PRODUCTION
Also called: leukocytes
Have nuclei but do not contain hemoglobin
Classified as granular or agranular depending on whether or not they contain granules.
Granular leukocytes include: ◦ Neutrophils◦ Eosinophils◦ Basophils
Agranular leukocytes include: ◦ Monocytes◦ Lymphocytes
B cells T cells Natural Killer Cells
WBC STRUCTURE AND TYPESSOME REVIEW…
Main function: Combat inflammation and infection
Through processes of :◦ Phagocytosis◦ Antibody production
WBC FUNCTIONS
Natural Killer Cells…FYI
Life span = few hours to a few days Normal blood contains 5000 to 10,000
WBCs per µL
WBC LIFE SPAN
Developed in red bone marrow leukocytes
Monocytes and granular leukocytes develop from myeloid stem cells
T and B cells develop from lymphoid stem cells
WBC PRODUCTION
Are derived from: ◦ Pluripotent stem cells
Structure:◦ Disk-shaped fragment◦ Lack a nucleus
Normal blood contains 250,000 to 400,000 platelets/µL
Platelets
Hemostasis sequence of responses that stops bleeding when blood vessels are injured
Three mechanisms that reduce blood loss:◦ Vascular Spasm
◦ Platelet Plug Formation
◦ Blood Clotting (Coagulation)
Hemostasis averts hemorrhage in smaller blood vessels
HEMOSTASIS
Complete notes for ‘Vascular Spasm’, ‘Platelet Plug Formation’, and ‘Blood Clotting’
BUT first…let’s watch this
http://www.mhhe.com/biosci/esp/2002_general/Esp/folder_structure/tr/m1/s7/trm1s7_3.htm
Read pages 387-388
Blood vessel damaged Its smooth muscle wall contracts immediately
◦ Initiated by pain receptors◦ Reduces blood loss
Few minutes to several hours Then other hemostatic mechanisms begin to
operate
Vasoconstriction narrowing of blood vessel; platelets accumulate at damage site-release chemicals to maintain vascular spasm
Vascular Spasm
Plugs form when platelets come into contact with parts of a damaged blood vessel
Platelet Plug Formation process:◦ Platelet Adhesion
Platelets contact and stick to damaged blood vessel (collagen fibers of connective tissue underlying damaged endothelial cells)
◦ Platelet Release Reaction Result of adhesion = platelets activated; characteristics change;
extend projections to connect and interact; interaction triggers release of chemicals from their vesicles; chemicals activate nearby platelets to sustain vascular spasm= decreased blood flow through injured vessel
◦ Platelet Aggregation Chemicals made platelets sticky so they stick together and gather
(aggregation); eventually enough to form a mass called platelet plug; completely covers hole in damaged vessel; blood loss ceases
Platelet Plug Formation
Serum: plasma minus clotting proteins◦ Clots are composed of a network of insoluble fibers (fibrin) filled with trapped
formed elements
Coagulation: formation of fibrin threads in a series of chemical reactions
Thrombosis: if blood clots too easily may result in a clot in an unbroken blood vessel
Hemorrhage: if blood takes too long to clot = uncontrolled bleeding Three stages of the clotting process:
◦ Prothrombinase formed◦ It is then converted to prothrombin (plasma protein formed in liver with help
of Vitamin K); then converted to thrombin◦ Thrombin converts soluble fibrinogen (plasma protein formed by liver) into
soluble fibrin; fibrin forms threads of clot
CLOTTING FACTORS: Calcium ions, enzymes, and molecules associated with platelets or damaged tissues activate each other throughout the clotting process
Clotting
Clot Retraction: consolidation or tightening of fibrin to reduce further damage
Blood Vessel Repair: fibrin threads attached to damaged surfaces of blood vessels gradually contract as platelets pull them in; as clot retracts it pulls edges of vessel closer together = decreasing risk of further injury
Clear Retraction and Blood Vessel Repair
Small, inappropriate clots dissolve through the process of fibrinolysis
What is the relationship between plasminogen and plasmin? PLASMINOGEN IS AN INACTIVE PLASMA ENZYME; IS
INCORPAORATED INTO A CLOT. PLASMINOGEN IS ACTIVATED TO PLASMIN BY CERTAIN
SUBSTANCES FOUND IN BOTH BODY TISSUES AND BLOOD. PLASMIN IS AN ACTIVE PLASMA ENZYME, WHEN PLASMA IS
FORMED IT CAN DISSOLVE CLOTS BY DIGESTING FIBRIN THREADS.
Heparin _Anticoagulant; prevents blood clots
Warfarin (Coumadin) Antagonist to Vitamin K thus blocking synthesis of 4 clotting factors; also prevents clotting
Hemostatic Control Mechanisms
Atherosclerosis accumulation of fatty substances on arterial walls; result = roughening of endothelial surfaces of blood vessels; now possibility to blood clots forming when blood flows too slowly (allows clotting factors to accumulate)
Pulmonary Embolism embolism in the lungs; blood clot, bubble of air, fat from broken bones, or piece of debris are causes
Clotting in Blood Vessels
RBC surfaces are marked by genetically determined glycolipids and glycoproteins called isoantigens or agglutinogens.◦ distinguishes at least 24 different blood groups
i.e. ABO, Rh, etc.
BLOOD GROUPS AND BLOOD TYPES
Based on two glycolipid isoantigens called A and B found on surface of RBCs.
If RBCs display only antigen A blood type Adisplay only antigen B blood type Bdisplay both antigens A & B blood type ABdisplay neither antigen blood type O
Plasma contains isoantibodies or agglutinins to the A or B antigens not found in your blood
anti-A antibody reacts with antigen A anti-B antibody reacts with antigen B
ABO Blood Group
Rh Blood Group Antigen was discovered in blood of Rhesus
monkey
People with Rh isoantigens on RBC surface are Rh+.
People with no Rh isoantigens on RBC surface are Rh-. ◦ Normal plasma contains no anti-Rh antibodies.
Rh negative mom and Rh+ fetus will have mixing of blood at birth thus the Mom's body creates Rh antibodies unless she receives a RhoGam shot soon after first delivery, miscarriage or abortion. In 2nd child, hemolytic disease of the newborn may develop causing hemolysis of the fetal RBCs
RISK ASSOCIATED WITH Rh- MOTHERS
Universal Donors and Recipients: People with type AB blood called “UNIVERSAL
RECIEPIENT” since have no antibodies in plasma.
People with type O blood cell called “UNIVERSAL DONOR” since have no antigens on their cells theoretically can be given to anyone.
Transfusion transfer of whole blood or blood components (RBCs only or plasma only) into the bloodstream
Transfusions
A B AB O
ANTIGEN A B A and B NEITHER
ANTIBODY B A NEITHER A and B
MAY RECEIVE FROM
A and O B and O ALL O
MAY DONATE TO
A and AB B and AB AB ALL
Transfusion chart