Term
| what are the main affects on systemic vasculature by neural and humoral mechanisms as opposed to local mechanisms? |
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Definition
| neural and humoral mainly regulate blood pressure, blood volume, and electrolite levels |
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Term
| what part of the brain regulates the autonomic system and where is it located? |
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Definition
| the medulla, at the base of the brain in the brainstem |
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Term
| what part of the brain receives information from the baroreceptors and chemoreceptors and where is it located? |
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Definition
| the medulla, at the base of the brain in the brainstem |
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Term
| true or false, the veins have a high degree of innervation whereas the arteries do not? |
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Definition
| false, the arteries have a high degree of innervation, whereas the veins have less |
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Term
| what large vascular structures do not have innervation? |
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Definition
| the cerebral vasculature and thoracic aorta |
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Term
| describe the synergistic role that adrenergic and cholinergic receptors play in blood flow. |
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Definition
during sympathetic stimulation blood flow through a vessel is dramatically decreased from normal; blockage of alpha receptors causes a dramatic increase in flow from normal; blockage of alpha and cholinergic (Ach) receptors causes a slight increase in flow from normal;
blockage of alpha, beta, and cholinergic receptors returns flow to normal.
this shows that all three receptors are working simultaneously. |
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Term
| what affect does sympathetic stimulation have on blood flow and fluid volume in a tissue? |
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Definition
| you have a reduction in both flow and therefore volume, upon blockage of the stimulation reactive hyperemia occurs and returns volume to normal |
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Term
| describe the role of the baroreceptor reflex on blood pressure. |
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Definition
| the receptors have a set point they want to remain at, they fire more frequently during periods of changing pressure and when the pressure is higher than desirable. they fire less during periods of static pulse pressure |
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Term
| what is the role of low pressure baroreceptors and where are they located? |
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Definition
| they are located in the RA and pulmonary arteries (cardiopulmonary receptors), they sense a change in the blood volume and stimulate an increase in HR to relieve the pressure, they also cause increased urine output and a decrease in ADH to lower blood volume |
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Term
| what affect do peripheral chemoreceptors have on circulation? |
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Definition
| they respond to changes in blood gases and pH, when O2 is low (CO2 high, pH low) they cause vasoconstriction in the peripheral vasculature to save O2 for the vital organs and they decrease HR (primary affect) |
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Term
| how are chemoreceptors overridden? |
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Definition
| by lung mechanoreceptors, if you are able to breathe than inhalation and stretch of the lungs stimulates the mechanoreceptors to override the chemoreceptors bradycardic action |
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Term
| what role do central chemoreceptors have on vasculature and blood flow? |
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Definition
| during periods of increased blood CO2, they increase sympathetic outflow causing vasoconstriction in order to shunt more blood to the brain and vital organs which lack innervation and are therefore not constricted |
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Term
| describe the renin-angiotensin system and its role in blood pressure/volume regulation. |
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Definition
| as blood flow to the kidneys decreases, the kidneys release renin which converts angiotensinogen to angiotensin I which is then converted to angiotensin II by ACE from the lungs (and other endothelial cells), angiotensin II causes salt retention and aldosterone release as well as vasoconstriction, all to raise blood volume and BP |
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Term
| describe angiotensin II's affects during acute and chronic periods of hypovolemia. |
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Definition
| angiotensin II does not do well to maintain BP over prolonged periods of time, however during periods of hemorrhagic shock it is able to maintain a more normal BP for a short duration |
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Term
| describe ANP's role in blood volume/pressure regulation and where is it found? |
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Definition
| it is found near the low pressure receptors in the atria, it is released by high blood pressure/volume and causes an increase in HR and CO, it acts as a diuretic and inhibits aldosterone and ADH release as well as cause vasodilation in an attempt to lower blood volume/pressure |
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Term
| how are the affects of endogenous vs exogenous epinephrine different? |
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Definition
endogenous epinephrine causes vasoconstriction and a decrease in CO and HR during a normal sympathetic immune response because it is trying to conserve blood for vital organs,
exogenous epinephrine causes an increased CO and HR because it stimulates beta 2 receptors leading to vasodilation and decreased peripheral resistance |
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Term
| how are the affects of endogenous vs exogenous norepinephrine different? |
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Definition
exogenous norepinephrine causes vasoconstriction and therefore an increase in peripheral resistance, it tries to increase CO, but these affects are outcompeted by the peripheral resistance and the baroreceptors stimulated by the increased BP
endogenous NE increases HR and CO as well as decreased peripheral resistance |
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