Term
Major determinants of coronary blood flow |
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Definition
perfusion pressure (most important factor) myocardial extravascular factor local myocardial metabolism neurohormonal control
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Term
| Why does the heart not receive blood during systole? |
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Definition
| when heart contracts, it generates pressures leading to the occlusion of the coronary vessels |
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Term
| Equation for coronary blood flow |
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Definition
| Q=(aortic pressure during diastole - cornary sinus P)/ coronary resistance |
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Term
| At what pt in the cardiac cycle is coronary blood flow shut off/sign. reduced? |
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Definition
| isovolumetric ventricular contraction |
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Term
| At what pt in the cardiac cycle does coronary blood flow get restored? |
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Definition
| isovolumetric ventricular relaxation |
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Term
| Effect of autoregulation of coronary blood flow. What would happen to flow in coronary system without it? |
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Definition
| It allows blood flow within coronary blood flow to continue at a constant flow between 50-140 mmHg. If they did not, the smooth muscle would contract upon increases in pressure, leading to occlusion of coronary blood flow. |
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Term
| Effect of decrease in oxygen and increase in adenosine on coronary blood flow |
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Definition
| vasodilation in coronary blood vessels, causing increase blood flow |
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Term
| Effect of increase in CO2, H, K, osmolarity on coronary blood vessels |
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Definition
| causes vasodilation, leading to increase coronary blood flow |
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Term
Effect of metabolism on autoreg. curve of Q and P |
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Definition
in high metabolism states, you operate on the "higher flow" end of the autoregulatory curve in low metabolism states, operate on "lower flow" end of autoregulatory curve
If you hit maximal dilation state, we override this autoregulatory mechanism, so we would get a linear relationship between coronary bp and coronary flow. |
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Term
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Definition
| increase in blood flow with increase in metabolic needs |
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Term
| Define reactive hyperemia |
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Definition
| increase blood flow in response to prior period of decreased blood flow, usually associated with build up of metabolic waste products and low oxygen conc. |
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Term
| Part of heart more susceptible to reactive hyperemia |
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Definition
| Endocardium (their AP is longer)- they depolarize sooner and repolarize later (see EKG) |
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Term
| How is it that the SA node fires at such a high rate the heart beat is no where near its intrinisic pacemaker rate? |
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Definition
| tonic parasympathetic activity |
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Term
| Role of neurohormonal control in coronary blood flow |
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Definition
| very little direct control, but they can control heart rate, which will indirectly affect myocardial metabolism |
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Term
Importance of vascular structure of circle of willis |
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Definition
| You have a circle, so if you had a ICA occlusion, it will preserve cerebral perfusion/flow. |
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Term
| Role of cerebral blood flow autoregulation |
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Definition
| maintains constant cerebral blood flow in conditions of increase pressure (50-150 mmHg) |
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Term
| equation for cerebral perfusion pressure |
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Definition
| CPP = MAP- intracranial P (ICP) |
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Term
| Common local vasodilator/increase blood flow signals of cerebral blood flow |
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Definition
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Term
| Resistance and Pressure in pulmonary circulations |
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Definition
| resistance is lowo so their are small rises in P when pulmonary flow increases (you can increase cardiac output without increasings your pulmonary pressure significantly) |
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Term
| Effect of low oxygen conc. on pulmonary circ. |
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Definition
| unlike the rest of the body, it elicits vasoconstriction, which will decrease flow |
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Term
| Role of gravity in pulm. circ. |
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Definition
| blood flow lowest at apex when standing |
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Term
| What factor controles pulmonary circulation the most? |
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Definition
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Term
| Predominant dilating factor of lungs |
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Definition
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Term
| mechansim of action of nitric oxide on lungs |
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Definition
activates guanylyl cyclase produce cGMP relax vascular smooth muscle
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Term
| Clinical pulmonary conditions to clinically use NO |
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Definition
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Term
| What makes NO a good treatment of respiratory hypertension? |
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Definition
rapidly inactivated by Hb, so no systemic vasodilation does not impair ventilation/perfusion matching
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Term
| blood flow in renal system |
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Definition
afferent arteriole Bowman's capsule glomerulus efferent arteriole peritubular capillary
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Term
| Effect of sympathetic activity on renal circulation. Effect of Ang II. |
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Definition
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Term
| Why is renal blood flow highly autoregulated? |
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Definition
| flow must remain constant despite changes in renal perfusion pressure |
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Term
Effect of sympathetic activity on skeletal muscle |
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Definition
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Term
Mechanism of action of symp. system on skel. muscle |
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Definition
norepi activate alpha one receptors cause vasoconstriction in skeletal muscle arterioles
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Term
| Effect of beta2 adrenergic agonist on pulm. circ. |
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Definition
| decrease pulm vascular resistance |
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Term
| Effect of high activation of symp. system on skel. muscle |
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Definition
adrenal glands release epi activate beta 2 receptors cause vasodilation of skel. muscle
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Term
Factors other than symp. system that can influence blood flow during exercise |
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Definition
local metabolites lactic acid adenosine potassium
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Term
| Innervation of cutaneous circulation |
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Definition
| dense tonic sympathetic activity |
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Term
| Role of symp. sys. on cutaneous circulation. How it responds to exercise? |
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Definition
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Term
| Effect of trauma to the skin on cutaneous circulation |
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Definition
increase vasoactive substances like histamine to vasodilate the response triple response focal red line assodciated with trauma red flare as vasodilation expands spatially local edema/swelling
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