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21 Cards in this Set
- Front
- Back
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Anatomy of Blood Vessels
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*Arteries carry blood away from heart
*Veins carry blood back to heart *Capillaries connect smallest arteries to veins |
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Vessel Wall
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Tunica interna (intima)
*smooth inner layer that *repels blood cells and platelets *simple squamous endothelium overlying a basement membrane and layer of fibrous tissue Tunica media *middle layer *usually thickest; smooth muscle, collagen, some elastic smooth muscle for vasomotion Tunica externa (tunica adventitia) outermost layer loose connective tissue with vasa vasorum |
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Tunica interna
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(intima)of Vessel Wall
*smooth inner layer that *repels blood cells and platelets *simple squamous endothelium overlying a basement membrane and layer of fibrous tissue |
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Tunica media
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layer of vessel wall
*middle layer *usually thickest; smooth muscle, collagen, some elastic smooth muscle for vasomotion |
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Tunica externa
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Third layer of vessel wall(tunica adventitia)
outermost layer loose connective tissue with vasa vasorum |
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Large Vessels
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Large Vein
Medium sized vein venule Large Artery Medium sized argery Arteriole |
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Control of Capillary Bed Perfusion
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Sphincters Open and Close
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Types of Capillaries
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Continuous - occur in most tissues
*endothelial cells have tight junctions with intercellular clefts (allow passage of solutes) Fenestrated - kidneys, small intestine *organs that require rapid absorption or filtration *filtration pores – spanned by very thin glycoprotein layer - allows passage of only small molecules Sinusoids - liver, bone marrow, spleen *irregular blood-filled spaces; some have extra large fenestrations, allow proteins and blood cells to enter |
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Continuous
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Continuous - occur in most tissues
*endothelial cells have tight junctions with intercellular clefts (allow passage of solutes) |
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Fenestrated
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Fenestrated - kidneys, small intestine
*organs that require rapid absorption or filtration *filtration pores – spanned by very thin glycoprotein layer - allows passage of only small molecules |
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Sinusoids
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Sinusoids - liver, bone marrow, spleen
*irregular blood-filled spaces; some have extra large fenestrations, allow proteins and blood cells to enter |
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Fenestrated Capillary
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Fenestrated Capillary
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Sinusoid in Liver
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Sinusoid in Liver
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Veins
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lower blood pressure: 10mmHg with little fluctuation
thinner walls, less muscular and elastic tissue expand easily, have high capacitance valves aid skeletal muscles in upward blood flow |
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Venules
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postcapillary venules more porous than capillaries
muscular venules have tunica media |
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Venous sinuses
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veins with thin walls, large lumens, no smooth muscle
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Blood Distribution
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Resting Adult
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Blood Pressure
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Force that blood exerts against a vessel wall
Measured at brachial artery of arm Systolic pressure: BP during ventricular systole Diastolic pressure: BP during ventricular diastole Normal value, young adult: 120/75 mm Hg Pulse pressure: systolic - diastolic *important measure of stress exerted on small arteries |
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Abnormalities of Blood Pressure
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Hypertension
*chronic resting BP > 140/90 *consequences **can weaken small arteries and cause aneurysms Hypotension *chronic low resting BP *caused by blood loss, dehydration, anemia |
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Peripheral Resistance
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Blood viscosity - by RBC’s and albumin
*decrease in viscosity with anemia, hypoproteinemia *Increase in viscosity with dehydration Vessel length pressure and flow decrease with distance (friction) Vessel radius - very powerful influence over flow *most adjustable variable, controls resistance quickly *vasomotion: change in vessel radius **vasoconstriction, vasodilation |
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vasomotion
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change in vessel radius
**vasoconstriction, vasodilation |
