Transcript CHAPTER 14

THE CARDIOVASCULAR SYSTEM: BLOOD
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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.
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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
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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
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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
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Viscosity (stickiness or thickness; resistance to
flow)
◦ greater than that of water
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Temperature range 38C or 100.4F.
pH range between 7.35 and 7.45
◦ Is this alkaline or acidic?
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8% of total body weight.
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Volume in average-sized adult male body
◦ 5 to 6 liters or 1.5 gallons.
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Volume in average-sized adult female body
◦ 4 to 5 liters or 1.2 gallons.
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Whole blood composed of two portions
◦ 55% blood plasma
 Liquid containing dissolved substances
◦ 45% formed elements
 Cells and cell fragments
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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
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Straw-colored liquid left when formed elements
removed from blood  blood plasma
Composition:
◦ 91.5 % water
◦ 7% proteins
◦ 1.5% solutes
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Principle solutes include:
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Proteins (Albumins, Globulins, and Fibrinogen)
Nutrients
Hormones
Respiratory gases
Electrolytes
Waste products
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Red Blood Cells (RBCs)
White Blood Cells (WBCs)
◦ Granular leukocytes
 Neutrophils
 Eosinophils
 Basophils
◦ Agranular leukocytes
 T and B lymphocytes and natural killer cells
 Monocytes
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Platelets
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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
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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
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Aka: ERYTHROCYTES
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Hemoglobin oxygen-carrying pigment
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STRUCTURE OF RBCs:
◦ Gives whole blood its red color
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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
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Live about 120 days
◦ Wear and tear on plasma membrane squeezing
through capillaries necessitates replacement…
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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.
Globin broken down into amino acids (to be used in protein synthesis).
Iron removed from heme portion associates with plasma protein called
transferrrin.
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)
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Erythropoiesis is the process in red bone marrow that results in
production of new red blood cells.
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.
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.
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Erythropoiesis formation of only RBCs in
the red bone marrow of adults
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Hypoxia  DEFICIENCY OF OXYGEN
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Also called: leukocytes
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Have nuclei but do not contain hemoglobin
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Classified as granular or agranular depending on whether or not
they contain granules.
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Granular leukocytes include:
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Agranular leukocytes include:
◦ Neutrophils
◦ Eosinophils
◦ Basophils
◦ Monocytes
◦ Lymphocytes
 B cells
 T cells
 Natural Killer Cells
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Main function:
Combat inflammation and
infection
Through processes of :
◦ Phagocytosis
◦ Antibody production
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Life span = few hours to a few days
Normal blood contains 5000 to 10,000 WBCs
per µL
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Developed in red bone marrow leukocytes
Monocytes and granular leukocytes develop
from  myeloid stem cells
T and B cells develop from  lymphoid stem
cells
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Are derived from:
◦ Pluripotent stem cells
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Structure:
◦ Disk-shaped fragment
◦ Lack a nucleus
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Normal blood contains 250,000 to 400,000
platelets/µL
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Hemostasis  sequence of responses that stops
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bleeding when blood vessels are injured
Three mechanisms that reduce blood loss:
◦ Vascular Spasm
◦ Platelet Plug Formation
◦ Blood Clotting (Coagulation)
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Hemostasis averts hemorrhage in smaller blood vessels
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Complete notes for ‘Vascular Spasm’, ‘Platelet
Plug Formation’, and ‘Blood Clotting’
BUT first…let’s watch this
http://www.mhhe.com/biosci/esp/2002_gener
al/Esp/folder_structure/tr/m1/s7/trm1s7_3.ht
m
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Blood vessel damaged
Its smooth muscle wall contracts immediately
◦ Initiated by pain receptors
◦ Reduces blood loss
 Few minutes to several hours
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Then other hemostatic mechanisms begin to
operate
Vasoconstriction narrowing of blood vessel;
platelets accumulate at damage site-release
chemicals to maintain vascular spasm
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Plugs form when platelets come into contact with
parts of a damaged blood vessel
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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
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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
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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
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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.
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Heparin  _Anticoagulant; prevents blood clots
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Warfarin (Coumadin)  Antagonist to Vitamin K thus blocking
synthesis of 4 clotting factors; also prevents clotting
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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
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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.
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Based on two glycolipid isoantigens called A and
B found on surface of RBCs.
If RBCs
display
display
display
display
only antigen A  blood type A
only antigen B  blood type B
both antigens A & B  blood type AB
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
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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.
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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
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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
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