I. Functions
A. Transport – gases, nutrients, hormones, wastes
B. pH balance – 7.35 – 7.45
C. Hemostasis
D. Defense – WBC’s and antibodies
E. Maintain body temperature
II. Characteristics
A. Specialized connective tissue
B. Properties
1. Temperature – 100.4F or 38C (slightly above body temp)
2. pH = 7.35 – 7.45
3. Viscosity – 5 times as viscous as water
C. Males – 5-6L, Females – 4-5L (about 7% of body weight)
III. Composition
A. Whole blood = 55% plasma + 45% formed elements
B. Plasma
1. 92% water
2. 7% plasma proteins – mostly produce by liver
a. albumins – osmotic pressure, transport of lipids
b. globulins –
1) immunoglobulins – antibodies
2) transport globulins; such as
-transferrin – Fe2+
-steroid binding proteins
-apolipoproteins
c. fibrinogen – hemostasis
d. others; FSH, LH, TSH
3. 1% Solutes
a. electrolytes
b. organic nutrients – glucose, lipids, amino acids
c. organic wastes – Nitrogenous wastes, bilirubin
d. gases
C. Formed Elements
1. Erythrocytes, Leukocytes, Platelets
2. Formed in red bone marrow (myeloid tissue)
3. Hemocytoblasts divide to form
a. lymphoid stem cells – lymphocytes
b. myeloid stem cells – all other formed elements
D. Erythrocytes
1. average female= 4.7 million/mm3 or l
average male = 5.2 million/mm3 or l
2. hematocrit or packed cell volume (PCV) – % of cellular
elements, mostly RBC’s (45%)
3. biconcave disc, 7.5 m
a. increase surface area for gas exchange
b. flexible and forms stacks
4. anucleate, lack normal organelles, 120 day lifespan
5. bag of Hemoglobin
a. 4 polypeptides – globin
1) 2 alpha chains
2) 2 beta chains
3) binds CO2
b. 4 Heme
1)Fe2+ – binds O2
2)oxyHb – bright red
3)deoxyHb – dark red (burgundy)
c. 4O2/Hb; 250millionHb/RBC; 1billionO2/RBC
6. Erythropoiesis
a. Erythropoietin (EPO) – hormone produced by
kidneys and stimulates RBC production
1) stimulates erythroblast division and Hb
maturation
2) release stimulated by hypoxia
-ex) high altitudes, low blood flow to
kidneys, damage to respiratory
membrane
b. Blood doping and EPO injections
c. Live at high altitudes
7. RBC Destruction
a. phagocytes in spleen, liver, RBM
b. Hb = globin and heme
RBC DESTRUCTION
1. Globin broken down to amino acids
2. Heme
-Fe2+ is reused
-biliverdin (green) to bilirubin (orange-yellow)
-bilirubin is released to blood and binds to albumin
-Liver forms conjugated bilirubin
-bile to intestines
-bacteria/O2 forms urobilins(yellow) and stercobilins(brown)
3.Iron
-travels in blood bound to transferrin
-stored in cells (hepatocytes) as ferritin
E. Leukocytes
1. nucleated, organelles
2. defense
3. 6,000 – 9,000/mm3
4. Characteristics
a. diapedesis – migrate out of blood to C.T.
b. amoeboid movement
c. chemotaxis – follow chemical path to infected/damaged
area
d. phagocytosis
1) microphages – eosinophils and neutrophils
2) macrophages – monocytes
5. Granulocytes
a. neutrophils (50-75%)
1) polymorphonuclear cells or poly’s
2) enter tissue after several hours, may survive
minutes to days
3) first to injured site
4) phagocytes – die after engulfing dozens of bacteria
5) pus
6) granules contain defensins/digestive enzymes
b. eosinophils (2-4%)
1) phagocytes
2) enter tissue after several hours, may survive
minutes to days
3) anti-histamines (reduce inflammation)
4) parasitic worm infections
c. basophils (.5%)
1) histamine and heparin
2) survival time unknown
3) also, stimulate local Mast Cells (promote inflam)
6. Agranulocytes
a. monocytes (2-8%)
1) remain in circulation 1 to 2 days, then enter
tissue and differentiate into macrophages
2) survive month or longer
3) phagocytes
b. lymphocytes (20-30%)
1) migrate from blood to tissue to blood
2) survive months to decades (memory cells)
3) most are in C.T. and lymphatic organs
4) B cells to plasma cells —-produce
antibodies (immune response)
5) T cells
F. Platelets
1. survive 9-12 days, removed by phagocytes in spleen
2. average – 350,000/mm3; 150,000 – 500,000/mm3
3. 1/3 reserved in spleen
4. fragments of a megakaryocyte
5. Functions – hemostasis
a. clotting chemicals, platelet plug, clot retraction
6.Hemostasis – 3 phases
a. vascular phase
b. platelet phase
c. coagulation phase
7. Vascular phase
a. vascular spasm – cutting wall of vessel causes
vasoconstriction
b. basement membrane is exposed to blood
c. endothelial cells release chemicals and become sticky
d. continues for about 30 minutes
8. Platelet phase
a. platelet adhesion and aggregation – platelets stick to wall
and to each other forming a platelet plug
b. platelets become activated and release substances
1) serotonin and thromboxane A2 = vasoconstriction
2) clotting factors – PF-3
3) Ca2+
c. begins within 15 seconds of damage
9. Coagulation phase
a. actual clot formation
b. clotting factors – Ca2+ and 11 different proteins
1) all produced by liver except 3 (damaged tissue and
platelets)
c. Extrinsic, Intrinsic, common pathways
10. Extrinsic pathway
a. begins with damaged tissue releasing Tissue Factor
b. Tissue Factor combines with Ca2+ and other factors to
activate Factor X
c. shorter and faster pathway to produce thrombin
11. Intrinsic pathway
a. activated Factor XII (activated by exposure to collagen or
glass), PF-3, and Ca2+ activate Factor X
b. also, responsible for clotting of glass surfaces
12. Common pathway
a. activated by Factor X
b. Factor X forms prothrombinase
c. prothrombin to thrombin
d. thrombin converts fibrinogen to fibrin (insoluble)
e. cascading reaction
f. positive feedback – thrombin stimulates Tissue Factor
formation and PF-3 release
13. Calcium and Vitamin K
a. vitamin necessary to synthesize prothrombin and 3 other
factors in liver
14. Clot retraction
a. RBC’s and platelets stick within fibrin mesh
b. platelets contract causing clot retraction (syneresis)
15. Fibrinolysis
a. plasminogen is activated by t-PA and thrombin
b. produces plasmin – enzyme that digests fibrin strands
G. Anticoagulents
1. Heparin
a. increases formation of antithrombin-III
b. antithrombin-III is found in plasma and inhibits thrombin
2. Coumadin
a. blocks vitamin K; necessary for synthesis of several
clotting factors produced by liver
3. t-PA (tissue plasminogen activator)
a. stimulates plasmin formation
b. natural part of fibrinolysis
4. Aspirin
a. inactivates platelet enzymes
5. anything that removes Ca2+
a. blood banks
H. Tests
1. Coagulation time – time for blood to clot in glass tube, 8-18 min
2. Bleeding time – time for small puncture to stop bleeding, 1-4 min
I..Centrifuge blood
a. hematocrit – 45%
b. buffy coat – platelets and WBC’s, <1%
c. plasma – 55%
J. Hemolysis and Crenation *OSMOSIS*
