PHYSIOLOGY
CARDIOVASCULAR PHYSIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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increase heart rate
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increase cardiac output
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increase the heart’s force of contraction
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increase parasympathetic response
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Detailed explanation-1: -During states of stress or anxiety, norepinephrine and epinephrine are released and bind to adrenergic receptors throughout the body which exert effects such as dilating pupils and bronchioles, increasing heart rate and constricting blood vessels, increasing renin secretion from the kidneys, and inhibiting peristalsis.
Detailed explanation-2: -Norepinephrine (NE) receptors in the hippocampus include the beta and alpha (1 and 2) receptors. NE action at the beta 1 receptor causes a decrease in the slow AHP by activation of cyclic AMP.
Detailed explanation-3: -Targeted activation of the beta-1 receptor in the heart increases sinoatrial (SA) nodal, atrioventricular (AV) nodal, and ventricular muscular firing, thus increasing heart rate and contractility. With these two increased values, the stroke volume and cardiac output will also increase.