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29 Cards in this Set
- Front
- Back
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Blood pressure |
Blood flows from areas of higher pressure to areas of lower pressure Pressure generated by ventricle contraction |
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Normal blood pressure in healthy human |
120/80 |
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Vasoconstriction |
Reduces blood flow Increases blood pressure |
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Vasodilation |
Increases blood flow Decreases blood pressure |
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Blood pressure in peripheral veins |
Skeletal muscle push on the vein and increase pressure Valves close to prevent backflow |
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Precapillary sphincter |
Smooth muscle that controls blood flow (at base of capillaries) |
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Precapillary sphincter causes |
Vasomotion - variable flow rate |
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Thoroughfare channels |
Always open so that blood can pass to venules Allows no blood flow to the rest of the capillaries |
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Capillaries |
Smallest vessels 8-10um Just big enough for single file erythrocytes |
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Function of capillaries |
Oxygen and nutrient delivery to tissues CO2 and nitrogenous waste (protein break-down product) removal |
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Permeability of capillaries |
O2 and CO2 by diffusion Depends on location |
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Continuous capillaries |
Tight junctions Lowest permeability |
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Fenestrated capillaries |
Perforated High permeability |
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Discontinuous capillaries |
Large gaps Very high permeability |
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Mammalian blood composition |
55% plasma <1WBCs & platelets ~45% RBCs |
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Types of white blood cells |
Basophils Lymphocytes Eosinophils Neutrophils Monocytes |
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Platelets |
In bone marrow |
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Red blood cells |
Formed in bone marrow Anucleated ~250 M hemoglobin molecules per RBC |
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Anucleated |
Mature cells lack a nucleus |
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Fibrin |
Aggregates into threads that form a clot |
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Enzyme cascade in blood clotting |
Prothrombin Thrombin cycles or goes on to Fibrinogen Fibrin |
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Erythrocyte life span |
120 days |
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Stem cells |
Multipotent Located in bone marrow |
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Multipotent |
Can form multiple types of cells |
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Erythropoietin (EPO) |
A hormone produced by the kidney Stimulates erythrocyte production when O2 delivery is low |
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Erythropoiesis |
Erythrocyte production |
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Location of continuous capillaries |
Skin,lung, central nervous system |
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Location of finestrated capillaries |
Exocrine glands, intestine, kidney |
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Location of discontinuous capillaries |
Liver, spleen, bone marrow |
