Chapter 11
Lecture Outline
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11.1 The Composition and
Functions of Blood
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A. Composition of blood
1.
Layers after centrifuging
a. Top layer – plasma; water and dissolved
substances
b. Bottom layer – formed elements
1) Upper – buffy coat – white blood cells
and platelets
2) Lower – red blood cells
2. Hematocrit – percent of blood volume
consisting of red blood cells
a. Normal – 45%
b. Males usually have a higher hematocrit
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Hematocrit
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B. Functions of blood
1.
Transport
a. Carries oxygen to tissues
b. Carries carbon dioxide and other wastes away
from tissues
c. Carries hormones and other chemicals
2.
Defense
a. Defends body against pathogens
b. Removes dead and dying cells
c. Blood clotting
3.
Regulation
a. Body temperature
b. Water-salt balance
c. Body pH
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11.2 Components of Blood
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A. Plasma
1.
2.
3.
Liquid portion of blood
About 92% is water
About 8% is composed various salts and organic
molecules
4.
Plasma proteins – help maintain homeostasis
a. Albumins – osmotic pressure and transport
b. Globulins
1) Alpha and beta – produced by the liver;
transport
2) Gamma – antibodies
c. Fibrinogen and prothrombin – functions in blood
clotting
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Blood Plasma Solutes
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B. Formed Elements
1.
Produced continuously in the red bone
marrow of the:
a. Skull
b. Ribs
c. Vertebrae
d. Iliac crests
e. Ends of long bones
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Composition of Blood
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2. Hematopoiesis
a.
Multipotent stem cells – red bone marrow
cells
b. Multipotent cells replicate by mitosis
c. Each daughter cell then differentiates
1) Myeloid stem cells further differentiate
a) Red blood cells
b) Granular leukocytes
c) Monocytes
d) Megakaryocytes
2) Lymphatic stem cells differentiate to
produce the lymphocytes and NK cells
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C. Red blood cells (erythrocytes)
1.
Introduction
a. Small, biconcave disks; anucleated
b. 4 to 6 million per mm3
c. Transport oxygen
d. Contain hemoglobin – 200 million/RBC
1) Respiratory pigment
2) Oxyhemoglobin is formed when
oxygen binds with hemoglobin – bright
red
3) Hemoglobin that is not combined with
oxygen is called deoxyhemoglobin –
dark maroon
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2. Erythropoiesis – production of RBCs
a. Myeloid stem cells give rise to erythroblasts
b. Erythroblasts divide many times
c. As they mature, erythroblasts gain many
molecules of hemoglobin and lose their
nucleus and most of their organelles
d. Reticulocytes released into circulation
e. Mature RBCs live about 120 days
f. About 2 million RBCs are produced per
second to keep RBC count in balance
g. Erythropoietin stimulates production and
maturation of RBCs
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Regulation of red blood cell production
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3. Destruction of red blood cells
a. Destroyed in the liver and spleen by
macrophages
b. Hemoglobin is released
1) Globin portion is broken down into amino
acids that are recycled by the body
2) Iron is recovered and returned to the
bone marrow for reuse
3) Heme portion is degraded and is
excreted as bile pigments bilirubin and
biliverdin by the liver
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4. Abnormal red blood cell counts
a. Anemia
1) Illness characterized by tiredness
2) Cells are not getting enough oxygen due
to decreased hemoglobin or decreased
number of red blood cells
3) Types
a) Hemolytic – increased rate of RBC
destruction
b) Sickle-cell – abnormal hemoglobin
c) Iron deficiency – low iron
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Types of anemia, cont
b.
d) Pernicious – lack of vitamin B12
e) Aplastic – bone marrow damage
f) Hemorrhagic – blood loss
Polycythemia – excessive RBCs
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D. White blood cells (leukocytes)
1.
Introduction
a. Usually larger than RBCs
b. Nucleated
c. Do not contain hemoglobin
d. About 5,000-11,000 per mm3
e. Functions include
1) Fighting infection
2) Destroying dead or dying body cells
3) Recognizing and killing cancerous cells
f. Derived from stem cells in the red bone
marrow
g. Able to leave the blood stream
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Mobility of white blood cells
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2. Types of white blood cells
a. Granular leukocytes
1) Neutrophils
a) Most abundant of the WBCs
b) First type of WBC to respond to an
infection
c) Engulf pathogens during phagocytosis
2) Eosinophils
a) Increase in number during parasitic
worm infections
b) Lessen an allergic reaction during an
allergic attack
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Granular leukocytes, cont
3) Basophils
a) Release histamines – dilates blood
vessels and causes contraction of
smooth muscle
b) Release heparin – prevents clotting and
promotes blood flow
4) Natural killer cells (NK cells) – destroy
mutated cells
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b. Agranular leukocytes
1) Lymphocytes
a) Specific immunity against particular pathogens
and their toxins
b) Recognize and destroy cancer cells
c) B lymphocytes produce antibodies
d) T lymphocytes attack and destroy any cell with a
foreign antigen
2) Monocytes
a) Largest of the WBCs
b) Differentiate into macrophages that phagocytize
pathogens, old cells, and cellular debris
1. Stimulate other WBCs to defend the body
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Hematopoiesis
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3. Abnormal white cell counts
a.
b.
c.
d.
Leukopenia – low count
Leukocytosis – high count
Leukemia – cancer
Differential count – count of individual
types of white blood cells
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11.3 Platelets and Hemostasis
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A. Platelets (thrombocytes)
1.
2.
3.
Fragments of megakaryocytes
150,000-300,000 per mm3 of blood
Lifespan about 10 days
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B. Hemostasis
1.
Cessation of bleeding; self-limiting and
confined to area of damage
2. Three events:
a. Vascular spasm – constriction of a
broken blood vessel; platelets also
release serotonin
b. Platelet plug formation
1) In a broken blood vessel, collagen
fibers are exposed
2) Platelets adhere to collagen and
aggregation of platelets result in a
platelet plug
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c. Coagulation – blood clotting
1) Requires many protein clotting factors
2) Two mechanisms for activation of clotting
a) Intrinsic mechanism – clotting factors
intrinsic to the blood – exposed collagen
b) Extrinsic mechanism – clotting factors
extrinsic to the blood (from damaged
tissue) - thromboplastin
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3) Four steps of coagulation
a) Prothrombin activator
is formed
b) Prothrombin activator
converts prothrombin
to thrombin
c) Thrombin converts
fibrinogen to fibrin
d) Fibrin threads wind
around platelet plug
and trap RBCs
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3. Clot retraction
a.
b.
Clot gets smaller as fibrin contracts
Enzyme, plasmin, breaks down the fibrin
network
4. Conditions that prevent unwanted clot
formation
a. Undamaged tissue
b. Smooth endothelial lining of blood
vessels
c. Anticoagulants in the blood - heparin
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C. Disorders of hemostasis
1. Thrombocytopenia – low platelet count
2. Hemophilia – inherited clotting disorders
caused by deficiencies of clotting factors
3. Thrombus – stationary blood clot
4. Embolus – dislodged blood clot
5. Thromboembolism – dislodged clot blocks a
blood vessel
a. Pulmonary thromboembolism
b. Cerebrovascular accident or stroke
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11.4 Blood typing and transfusions
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A. Blood Transfusion
1.
2.
Transfer of blood from one individual into
the blood of another
Blood must be typed so that agglutination
does not occur
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B. ABO blood groups
1.
2.
3.
4.
5.
Based on the presence or absence of
inherited antigens and antibodies
Type A blood has type A antigen and anti-B
antibodies
Type B blood has type B antigen and anti-A
antibodies
Type AB blood has both antigens and
neither antibodies
Type O blood has no AB antigens and both
antibodies
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ABO Blood Types
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C. Agglutination
1. Agglutination occurs if antibodies in the
plasma combine with the antigens on the
surface of the RBC
2. Type O blood is the universal donor
3. Type AB blood is the universal recipient
4. Autotransfusion technology and blood
substitutes are alternatives to matching
blood types
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Cross-matching before a transfusion
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Transfusions
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D. Rh blood groups
1.
Rh- individuals do not have antibodies to
the Rh factor until they are exposed to it
either through a transfusion or by carrying
an Rh+ baby
2. Hemolytic disease of the newborn
a. May occur in subsequent pregnancies
with an Rh+ baby and an Rh- mother
b. Bilirubin in the blood of the newborn can
lead to brain damage or death
c. Prevented by giving Rh- women an Rh
immunoglobulin injection (RhoGAM)
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Hemolytic disease of the newborn
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11.5 Effects of aging
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Effects of Aging
A.
Anemias increase
1. Iron deficiency anemia
2. Pernicious anemia
B. Leukemia increases
C. Clotting disorders, such as
thromboembolism increase
1. Associated with arteriosclerosis
2. May be controlled by diet and exercise
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