Which cells are responsible for secreting catecholamines?

Which cells are responsible for secreting catecholamines?

• A. Chromaffin
• B. Langerhans
• C. Enkephalin
• D. Parietal

Answer: (A)

Catecholamines, such as epinephrine and norepinephrine, are released by chromaffin cells located in the adrenal medulla. These cells come from neural crest tissue and act like a modified sympathetic ganglion: when preganglionic sympathetic fibers release acetylcholine onto chromaffin cells, they secrete catecholamines directly into the bloodstream, producing systemic “fight-or-flight” effects such as increased heart rate, bronchodilation, and mobilization of glucose. Other options don’t fit because they refer to different cell types with distinct roles: Langerhans cells are in the pancreas and regulate insulin and glucagon; enkephalin is an endogenous opioid peptide involved in pain signaling; parietal cells secrete gastric acid in the stomach. Therefore, chromaffin cells are the ones responsible for secreting catecholamines.

Catecholamines, such as epinephrine and norepinephrine, are released by chromaffin cells located in the adrenal medulla. These cells come from neural crest tissue and act like a modified sympathetic ganglion: when preganglionic sympathetic fibers release acetylcholine onto chromaffin cells, they secrete catecholamines directly into the bloodstream, producing systemic “fight-or-flight” effects such as increased heart rate, bronchodilation, and mobilization of glucose.

Other options don’t fit because they refer to different cell types with distinct roles: Langerhans cells are in the pancreas and regulate insulin and glucagon; enkephalin is an endogenous opioid peptide involved in pain signaling; parietal cells secrete gastric acid in the stomach. Therefore, chromaffin cells are the ones responsible for secreting catecholamines.