Final answer:
Epinephrine and norepinephrine are secreted by the chromaffin cells of the adrenal medulla and play crucial roles in the body's stress response, including raising heart rate and blood glucose levels. The correct option is (B)
Step-by-step explanation:
Epinephrine and norepinephrine are secreted by the B) chromaffin cells of the adrenal medulla. These hormones are fundamentally involved in the body's fight or flight response. Upon release, epinephrine and norepinephrine increase heart rate and breathing rate, intensify cardiac muscle contractions, elevate blood pressure, and boost blood glucose levels. They also promote the breakdown of glucose in skeletal muscles and the mobilization of stored fats from adipose tissue.
The adrenal medulla houses cells that produce these hormones: epinephrine, accounting for 75 to 80 percent of its secretions, and norepinephrine. These hormones exert their effects by acting on the smooth muscles of blood vessels, causing constriction. Specifically, they constrict the arterioles leading to the kidneys; this can temporarily halt kidney function and initiate the renin-angiotensin-aldosterone system. This response redirects blood flow to critical areas like the liver, heart, and muscles during stress-induced or emergency situations.