Download Comparative Vertebrate Physiology

Human Anatomy and
Physiology
Blood and hemodynamics
Blood composition
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Plasma and formed elements
Formed elements
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Erythrocytes, leukocytes, platelets
Blood composition
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Hematocrit
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<45% anemia (O2 delivery problems)
>45% polycythemia (circulation problem)
Plasma
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Contents
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90% water
Protein (albumin acts as a buffer)
Fats, amino acids, salts, gases, enzymes,
hormones
Narrow osmolality range
Erythrocytes
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Manufactured by erythropoiesis
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Committed cell: will form a specific cell type
Erythroblasts undergo rapid mitosis
Reticulocytes enter blood stream (2% of blood)
Erythropoiesis
Erythrocytes
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Function: gas exchange
Oxy- and deoxyhemoglobin
Erythrocytes
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Destruction (3 - 4 months)
Trapped in spleen and destroyed by
macrophages
Globin is recycled into amino acids
Iron is used to make new RBC’s
Rest of heme group converted to bilirubin
Bilirubin appears in urine and feces
Erythrocyte disorders
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Athlete’s anemia
Thalassemia
Sickle-cell anemia
Blood doping among athletes
Leukocytes
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The only complete cells
Protect against invasion
Move out of blood by diapedesis
Move through tissues by amoeboid motion
Follow chemical trails by chemotaxis
Leukocytes
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Types
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Granulocytes: contain cytoplasmic granules
 Neutrophils, eosinophils basophils
Agranulocytes: without cytoplasmic granules
 Lymphocytes, monocytes
Abundance: Never Let Monkeys Eat Bananas
Neutrophils
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Characteristics
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Multilobed (3 - 6 lobes) nucleus
Twice the size of RBC’s
Phagocytose bacteria
Eosinophils
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Characteristics
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Bilobed nucleus
Course granules stain deep red to crimson
Twice the size of RBC’s
Release digestive enzymes to kill worms (too large to
be phagocytosed)
Basophils
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Characteristics
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Course, dark purple, black granules
Twice the size of RBC’s
Release histamine (inflammatory chemical), attract
other WBC’s to the area
Lymphocytes
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Characteristics
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Large, dark purple nucleus
About the size of RBC’s
Act in immune response
Monocytes
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Characteristics
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Large, dark purple nucleus
Three times the size of RBC’s
Leave blood stream acting to phagocytose viruses and
bacteria
Platelets
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Megakaryocytes (bone) rupture through
sinusoid capillaries
Enucleate, age quickly (10 days)
Hemostasis
Hemostasis
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Phases
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Vascular spasm
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Platelet plug formation
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Vasconstriction reduces blood flow
Platelets swell, and adhere to each other
Coagulation
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Blood transformed from liquid to a gel
Hemostasis
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Phases
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Prothrombin activator
formed
Conversion into thrombin
Fibrin seals the hole
RBCs and fibrin mesh
Blood typing
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RBC plasma membranes bear specific
glycoproteins recognized by the body
Glycoproteins called agglutinogens
ABO blood group (A, B, AB or O)
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O (common), AB (least common)
Blood typing
Rh blood group
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Rh factor: 8 Rh agglutinogens
C, D, E antigens most common
Carrying Rh symbolized by +
Blood groups reported together
(i.e., O+)
Rheology
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The study of blood flow
Viscosity (i.e., polycythemia)
Rheology
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Flow rate = 1/viscosity
Rheology
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Flow rate is directly proportional to
differences in pressure
F ∞ P1 - P2 or (∆P)
Rheology
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Flow rate is indirectly proportional to
vessel length (F = 1/L)
Rheology
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Flow rate is directly proportional to the
fourth power of the radius of the vessel
F ∞ r4
Hemodynamics
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Rate of blood flow highest in smallest cross
sectional areas
Functional significance
Total
area
Velocity
Blood flow
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Laminar flow
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Continuous (small vessels)
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Pulsatile (large vessels)
Blood flow
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Turbulent flow
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Definition (obstruction, sharp turns, high flow rate)
Occurs after aortic and pulmonary valves or
valves in veins
Compliance
Tendency of blood vessel volume to
increase as pressure increases
C = ∆V/∆P
P1=160 mmHg, P2=120 mmHg, V1=5 l/min.
V2=3 l/min.
C = 0.05 kPa-1
 Are veins or arteries more compliant ?
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Compliance
8X more blood
3X more elasticity
24X more compliant