Term
| Requirements for CV Vasculature |
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Definition
1. Closed circuit
2. Equilibrium between inflow of nutrients and outflow of cell products and waste.
3. Need to be able to get O2 and nutrients to middle cells of multicellular organisms.
4. Cell lining needs to be made of special cell type (Endothelial cells, toughest cell in body, able to withstand enormous pressure). |
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Term
| Characteristics of vasculature |
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Definition
1. Withstands high pressure from CO.
2. Smooths out flow through rebound of the aorta.
3. Regulate flow/pressure through tuning resistance.
4. Exchange of materials, different vessels have different leakiness=different amounts of exchange.
5. Return blood to the heart. |
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Term
| Types of circulatory systems |
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Definition
1. Blood (systemic, pulmonary, portal)
2. Lymphatics.
Most fluid are intracellular so circulatory systems carry only a fraction of the total body fluid. |
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Term
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Definition
1. Tunica Intima
2. Tunica Media (virtual layer in small vessels)
3. Tunica Adventitia (virtual layer in small vessels) |
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Term
| Layers within Tunica Intima |
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Definition
From innermost to outermost:
1. Endothelial cells
2. Basal lamina
3. Subendothelial Space
4. Internal elastic lamina |
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Term
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Definition
| Used for regulating flow through the vessel through dilation/constriction of smooth muscle. Aligned in concentric orientation around flow. Collagen type III fibers and elastic fibers transduce force of smooth muscles. Smooth muscles are connected via gap junctions. Nerve fibers secrete neurotransmitters to outside of tunica media, signal propogated to all smooth muscle cells via gap junctions. Key cell type affected in vascular disease. |
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Term
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Definition
| Contains fibroblasts and Type I collagen fibers and elastic fibers with some smooth muscle. Used for structural support. Higher pressure vessels contain more tunica adventitia. Also have vasa vasorum blood vessels running inside layer if there are extremely tight tight junctions in endothelial cells, which limit diffusion of nutrients. Run longitudinally to blood flow. |
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Term
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Definition
| Allows for distortion of endothelial layer during systole (high pressure), acts as a cushioning space. Found only in larger vessels that see high pressure blood. Consists of mostly loose connective tissue (type I + elastic fibers) in longitudinal orientation to blood flow, used to withstand high pressure and smooth out flow. Contains some fibroblasts and smooth muscle cells. |
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Term
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Definition
| Sheet of elastic fibers in outermost layer of tunica intima, found only in larger vessels. |
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Term
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Definition
Found in innermost layer of tunica intima, used for exchange of gases and nutrients. Very attenuated and thin (.2-.4 microns).Have tight junctions with variable leakiness and gap junctions. Has neg. charged surface which repels RBCs (also neg. charged), creates friction free surface (non-thrombogenic). Longitudinally organized to follow flow. Uses hydrostatic, osmotic, concentration gradients, diffusion, and active transport to exchange materials.
Can also make factors (clotting) and be modulated by regulatory molecules. |
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Term
| Large elastic artery properties |
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Definition
Vessels undergo high pressure=need for more deformation with rebound.
Results in well developed subendothelial space cushioning (thicker tunica intima) along with high elastic fiber content in tunica media (40-70 layers, for rebound) and a thin tunica adventitia (most of work done by tunica media). Elasticity with rebound smooths out blood flow, maintains movement of blood after heart pump (diastolic pressure).
Wall thickness=1/10 diameter of the vessel |
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Term
| Muscular artery properties |
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Definition
Want to conduct blood under pressure and regulate lumen diameter.
.5mm-1cm in diameter. Wall thickness is 1/4 of diameter (thicker than elastic artery). Thinner subendothelial space. Tunica media has 3-40 layers of smooth muscle cells with reticular and elastic fibers, most well developed layer. Can see internal elastic lamina very distinctly. |
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Term
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Definition
30-40 microns in diameter.
Have all 3 tunic layers, not well defined.
Tunica intima is essentially just endothelial cells and basement membrane.
NE vasoconstricts, NO dilates.
Tunica media has 1-3 smooth muscle cell layers.
Little to no subendothelial space, internal elastic lamina, or tunica adventita.
Terminal end has metarteriole that cycles between opened and closed every 8 seconds to allow time for exchange in capillaries. Regulates blood flow and pressure. |
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Term
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Definition
7-9 microns in diameter, consists of endothelial cells maintained by pericytes.
No tunica media or adventitia. |
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Term
| Forces involved in capillary exchange |
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Definition
1. Hydrostatic
2. Osmotic (venule end)
3. Diffusion gradients for exchange of O2 and CO2
4. Active Transcytosis |
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