MEDICAL
HEART AND PERICARDIUM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Which of the following increases heart rate?
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cold
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low levels of potassium
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epinephrine and norepinephrine
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None of the above
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Explanation:
Detailed explanation-1: -Cocaine increases the plasma concentrations of catecholamines including epinephrine and norepinephrine by inhibition of peripheral re-uptake and central sympathetic system stimulation. Increased levels of these catecholamines potentiate activation of the beta-1 receptor and thus lead to increased heart rate.
Detailed explanation-2: -Norepinephrine does not increase heart rate. The main beneficial effect of norepinephrine is to increase organ perfusion by increasing vascular tone.
Detailed explanation-3: -The sympathetic nervous system releases norepinephrine (NE) while the parasympathetic nervous system releases acetylcholine (ACh). Sympathetic stimulation increases heart rate and myocardial contractility.
There is 1 question to complete.