Download Comparative Vertebrate Physiology

Comparative Vertebrate
Physiology
Blood and hemodynamics
Blood composition
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Plasma and formed elements
Formed elements
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Erythrocytes, leukocytes, platelets
Hematocrit
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<45% anemia (O2 delivery problems)
>45% polycythemia (circulation problem)
Plasma
WBC’s, platelets
RBC’s
Plasma
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Contents
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90% water
Protein (albumin)
Fats, amino acids, salts, gases, enzymes,
hormones
Narrow osmolality range in mammals only
Erythrocytes
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Most verts. have a nucleus (exceptions some fish,
amphibians, humans)
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Shape (oval in Aves,spherical, elliptical to biconcave
disc in mammals)
Leukocytes
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Protection against invasion
Granulocytes
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Neutrophils, eosinophils, basophils
• Agranulocytes
• No cytoplasmic granules
• Lymphocytes, monocytes
Platelets
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Fragments of bone marrow
(megakaryocytes)
Clotting function
Age quickly (enucleate)
Erythropoiesis
1. Ribosome manufacturing
2. Hb synthesis and accumulation
3. Nucleus and organelle ejection
Erythropoiesis
Rheology
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Relationship between pressure and flow
of fluid
1. Viscosity
Rheology
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Flow rate = 1/viscosity
Rheology
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Flow rate is directly proportional to
differences in pressure
Rheology
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Flow rate is indirectly proportional to
vessel length
Rheology
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Flow rate is directly proportional to the
fourth power of the radius of the vessel
Hemodynamics
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Rate of blood flow slowest in highest cross
sectional areas
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Functional significance
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
Blood flow
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Reynold’s number determines whether
flow is laminar or turbulent
Re
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Directly proportional to velocity
Directly proportional to the radius
Inversely proportional to viscosity
Blood flow