Short answer question
Explain how the adrenal medulla and sympathetic nervous system function as a closely integrated system.
i. The adrenal medulla is the inner region of the adrenal gland. It is the modified sympathetic ganglion of the autonomic nervous system (ANS).
ii. The chromaffin cells of the adrenal medulla secrete hormones rather than releasing a neurotransmitter. These cells are innervated by sympathetic pre-ganglionic neurons of the autonomous nervous system (ANS).
iii. The autonomous nervous exerts direct control over the chromaffin cells, thus the hormones – adrenaline and nor adrenaline can be released quickly into the blood.
iv. The impulses from the hypothalamus stimulate sympathetic pre-ganglionic neurons which in turn stimulate the chromaffin cells to secrete adrenaline to nor-adrenaline.
v. The fight-or-flight response is initiated by nerve impulses from the hypothalamus to the sympathetic nervous system, including the adrenal medulla. This response rapidly increases circulation, promotes ATP production, and decreases non-essential activities.
Thus, the adrenal medulla and sympathetic nervous system function in a closely integrated manner.