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29 Cards in this Set
- Front
- Back
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What are the long-term regulatory changes that adjust blood flow? (2) |
- Change in physical size of CV - Increase in number of blood vessels |
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What term is used for the growth of new blood vessels? |
Angiogenesis |
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What percentage of blood is in the venous system? |
61% |
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What two characteristics help veins act as blood reservoir? |
- Physical size - High compliance |
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Can veins constrict? |
Yes (as per SNS) |
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What is the condition of varicose veins? |
venous valves become incompetent and blood thus backs up and engorges veins |
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What effect does skeletal muscle movement have on the pressure inside veins? |
Drops it |
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What effect does respiration have on abdominal and thoracic venous return? |
Increases pressure in abs while decreasing thoracic venous pressure |
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Does blood flow to the brain change during exercise? |
No |
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In what blood vessel is flow the slowest? |
Capillaries |
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What equation helps define diffusion rate of capillaries? |
Qx = Px A (Cpx-Cifx)
Qx = diffusion rate A = area Px = permeability coefficient Cpx = concentration of a substance in plasma Cifx = conc of substance in interstitial fluid |
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How is the capillary exchange of lipids and water regulated? |
By changing number of capillaries |
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How is blood flow regulated in capillary beds? |
Contraction and dilation of capillary sphincters |
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How do capillary beds differ in different tissue? |
Space between clefts are adjusted for variable diffusion rates |
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What relationship does blood flow have with nutrient/waste exchange rate? |
Slower the flow, the greater the exchange |
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How is glucose exchange increased in tissue that has increased demand? (3) |
- Capillary recruitment - Steeper concentration gradients - Increased blood flow |
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What mediates the movement of ionic solutes like Na across the capillary? |
Simple diffusion through the intracellular clefts |
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What are the major proteins in plasma that determine plasma oncotic pressure? (3)
Which has the greatest impact? |
- Albumin - Globulins - Fibrinogen
Albumin has the greatest impact |
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What effect does arteriole vasoconstriction have on capillary hydrostatic pressure?
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Decreases it
Absorption |
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What effect does arteriole vasodilation have on capillary hydrostatic pressure?
Does this lead to net filtration or absorption? |
Increases it
Filtration |
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What effect does CHF have on plasma hydrostatic pressure?
Plasma oncotic pressure?
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Plasma hydrostatic pressure increases
Plasma oncotic pressure decreases |
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What effect does dehydration have on plasma hydrostatic pressure?
Plasma oncotic pressure? |
Plasma hydrostatic pressure does not change
Plasma oncotic pressure increases (less water in blood) |
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What percentage of fluid goes through the lymphatic system? |
10% |
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What is the difference between contraction of vascular smooth muscle versus striated muscle? (3) |
- Smooth muscle contracts slower than striated muscle
- It has a greater shortening degree than skeletal muscle
- The duration of contraction of smooth muscle can be much longer |
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How is smooth muscle able to maintain a sustained contraction for much longer time than striated muscle? |
The Actin/myosin can be locked into the cross-bridge state by active calcium-calmodulin myosin light-chain kinase |
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What additional mechanism can cause myosin to produce greater force in smooth muscle contractions? |
Inhibition of myosin phosphatase by rho kinase leads to enhanced myosin sensitivity to calcium |
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How do smooth muscle cells allow for relaxation? |
Sequestering calcium or pumping it out of the cell |
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What does NO activate? |
soluble guanylate cyclase to increase cGMP |
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Which blood vessel has the most resistance? |
Arterioles |
