Question

question 7
which of the following factors would cause an increase in the heart rate?
select all that
apply
epinephrine
parasympathetic stimulation
exercise
cold

Explanation:

• Epinephrine: Also known as adrenaline, it is released by the adrenal glands. It acts on the heart's beta - 1 receptors, increasing the heart rate (chronotropic effect), contractility (inotropic effect), and conduction velocity (dromotropic effect).
• Parasympathetic stimulation: The parasympathetic nervous system (via the vagus nerve) releases acetylcholine. It acts on the heart's muscarinic receptors, generally decreasing the heart rate. So, it does not cause an increase in heart rate.
• Exercise: During exercise, there is an increase in sympathetic nervous system activity. This leads to the release of norepinephrine (and also an increase in epinephrine from the adrenal medulla). The sympathetic stimulation increases the heart rate to meet the increased oxygen demand of the working muscles.
• Cold: Cold exposure can initially cause a reflex bradycardia (decrease in heart rate) due to peripheral vasoconstriction and a baroreceptor - mediated response. However, if the cold exposure is severe and leads to hypothermia, there can be various cardiac arrhythmias, but an increase in heart rate as a direct and common effect of cold is not typical.

Answer:

Epinephrine, Exercise