Comparative Vertebrate Physiology
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Transcript Comparative Vertebrate Physiology
Comparative Vertebrate
Physiology
Blood and hemodynamics
Blood composition
Plasma and formed elements
Formed elements
Erythrocytes, leukocytes, platelets
Hematocrit
<45% anemia (O2 delivery problems)
>45% polycythemia (circulation problem)
Plasma
WBC’s, platelets
RBC’s
Plasma
Contents
90% water
Protein (albumin)
Fats, amino acids, salts, gases, enzymes,
hormones
Narrow osmolality range in mammals only
Erythrocytes
Most verts. have a nucleus (exceptions some fish,
amphibians, humans)
Shape (oval in Aves,spherical, elliptical to biconcave
disc in mammals)
Leukocytes
Protection against invasion
Granulocytes
Neutrophils, eosinophils, basophils
• Agranulocytes
• No cytoplasmic granules
• Lymphocytes, monocytes
Platelets
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
Relationship between pressure and flow
of fluid
1. Viscosity
Rheology
Flow rate = 1/viscosity
Rheology
Flow rate is directly proportional to
differences in pressure
Rheology
Flow rate is indirectly proportional to
vessel length
Rheology
Flow rate is directly proportional to the
fourth power of the radius of the vessel
Hemodynamics
Rate of blood flow slowest in highest cross
sectional areas
Functional significance
Blood flow
Laminar flow
Continuous (small vessels)
Pulsatile (large vessels)
Blood flow
Turbulent flow
Definition (obstruction, sharp turns, high flow rate)
Occurs after aortic and pulmonary valves
Blood flow
Reynold’s number determines whether
flow is laminar or turbulent
Re
Directly proportional to velocity
Directly proportional to the radius
Inversely proportional to viscosity
Blood flow