Question

multiple choice 2 points

the adrenal medulla secretes mostly _______

acetylcholine (ach)
endorphins
norepinephrine (noradrenaline)
dopamine
epinephrine (adrenaline)

Explanation:

Identify the function of the adrenal medulla

The adrenal medulla is the inner portion of the adrenal gland, functioning as a modified sympathetic ganglion. In response to stimulation by preganglionic sympathetic neurons, chromaffin cells in the adrenal medulla release catecholamines directly into the bloodstream.

Compare the secreted catecholamines

The adrenal medulla secretes two primary catecholamines: epinephrine (adrenaline) and norepinephrine (noradrenaline). Under physiological conditions, epinephrine constitutes approximately 80% of the total secretion, while norepinephrine accounts for the remaining 20%.

Select the correct option

Since epinephrine (adrenaline) makes up the vast majority (about 80%) of the secretions from the adrenal medulla, it is the substance secreted "mostly" by this structure.

Answer:

• acetylcholine (ACh)
• endorphins
• norepinephrine (noradrenaline)
• dopamine
• epinephrine (adrenaline) (Correct answer)