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Cardiovascular System: Blood
Advanced Anatomy & Physiology
Tony Serino, Ph.D.
Biology Department
Misericordia Univ.
Blood
• Liquid connective tissue
• Arises from hemopoietic tissue:
1. myeloid tissues (Red bone marrow)
2.lymphoid tissues (thymus, spleen, lymph
nodes, tonsils, etc.
• In fetus, liver and yolk sac are hemopoietic
Properties of the Blood
• Volume 4-6L (5-6L men, 4-5L women)
based on body size (8% of total body
weight)
• pH 7.4 + 0.1
• 5X the viscosity of water
• Hematocrit = 45
Blood Composition
Plasma Composition
• 90% water
• 10% suspended or dissolved constituents
• Plasma Constituents (10%)
–
–
–
–
0.9% NaCl + other electrolytes
Nutrients
Plasma proteins: albumin, globulins, fibrinogen
Dissolved gases: O2, CO2, N2
Functions of the Blood
•
•
•
•
Transportation media
Osmoregulation
Acid-Base balance
Protection
Hemopoiesis (RBC development)
• Rate controlled by erythropoietin secretion
• Availability of Fe++, folic acid, vitamin B12 and
amino acid precursors for hemoglobin production
RBC Production Control
Formed Elements
RBC (erythrocyte)
• Lives 120 days
• Non-nucleated
biconcave disc
• 4.5-5.5 million/mm3
• 1/3 of cytoplasm is
hemoglobin
Rouleau
Hemoglobin
Hemoglobin Metabolism
Point Mutation in Sickle Cell
Sickle Cell
Anemia
Blood Types
Anti-D
Blood
Typing
ABO Blood Group Summary
WBC
Development
WBC Development
Distribution of WBC
Neutrophil
Most abundant circulating WBC (55-65% of WBCs), highly
phagocytic, 1st to arrive at site of infection
Eosinophil
2-4% of WBC, combat irritants
that trigger inflammation,
phagocytic for Ag-Ab complexes,
destroy worm infections, limit
inflammation
Basophil
Least abundant WBC (0.5% of WBC), trigger inflammation,
contain vesicles with vasoactive compounds
Monocyte
3-8% of WBC, highly phagocytic and chemotaxic, arrive second
to neutrophils at site of infection but in more massive numbers,
can undergo diapedesis; some take up permanent residence in
some tissues (often has a C-shaped nucleus)
Lymphocyte
Second most abundant WBC (20-30% of WBC),
function in specific immunity, two types: T and B
cells
Platelet Development
Platelets
• 150-400
thousand/mm3
• 2-4 mcm in diameter
• Function in clotting
and vessel repair
Hemostasis (stoppage of bleeding)
• Extravascular Mechanisms
– Tightening of skin and muscles around injury
– Behavior response (elevate, applied pressure)
• Vascular Mechanisms
– Vasoconstriction (vascular spasms)
• Intravascular Mechanisms
– Platelets –plug formation and factor secretion (PF3)
– Clotting factors (extrinsic and intrinsic system)
Platelet Plug and Clotting
Platelet aggregation is
increased by the stuck
platelets releasing
Thromboxane which
stimulates
vasoconstriction and
attracts more platelets to
area. Prostacyclin
inhibits this and is
released by non-damaged
endothelial cells
The common
clotting pathway
Platelet
stimulated
(TF)
(PF3) or (TF)
(PF3)
(Stabilizing Factor)
Coagulation Summary
1. Coagulation may be triggered by intrinsic or extrinsic
pathway, but in the body the extrinsic path is the one
most commonly used.
2. Activated Factors X, V, Ca2+, and PF3 or TF combine
to change Xa into prothrombin activator which
catalyzes prothrombin to thrombin
3. Thrombin then catalyzes Fibrinogen to Fibrin turning
the blood into a gel-like state
4. Activate Factor XIII stabilizes and strengthens the
fibrin.
5. Finally the platelets in the clot contract, squeezing the
plasma from the clot. (Clot retraction)
6. After 2 days, enzymes in clot activate plasminogen
into plasmin with begins dissolving clot
Fibrin Clot
Bleeding and Coagulation Tests
• Bleeding time –the time it takes a small wound to
stop bleeding
• Coagulation (clotting) time –the time it takes to
form a blood to clot in a test tube (test intrinsic
system) but not that sensitive
• Thrombin time –measures the time for blood to
clot in a tube when thrombin is added
• Prothrombin time (pro-time, PT) –evaluates the
extrinsic mechanism
• Partial Thromboplastin time (PTT) –tests the
intrinsic system, more sensitive than clotting time
Bleeding Disorders
• Thrombocytopenia
– –decrease number of platelets
• Impaired Liver Function
– responsible for many of the clotting factors in the blood
– Vit. K used as co-factor in many clotting factor syntheses; liver
bile salts help in absorbing this vitamin
• Hemophilia –hereditary bleeding disorders
– Class A (classical) –deficiency of factor VIII; most common
hemophilia (83%)
– Class B deficiency of factor IX
• A & B is sex (X) linked trait; mainly seen in males
– Class C deficiency of factor XI –less severe; seen in both sexes