2020 · Q16
In human body, the hormone which is secreted into blood and which controls the rate of heart beat is?
general-sciencebiology-human-body
- AAdrenaline
- BThyroxine
- CInsulin
- DTestosterone
Explanation
Adrenaline (epinephrine), secreted by the adrenal medulla into the blood during stress or excitement, increases both the rate and force of the heartbeat. Thyroxine sets the basal metabolic rate, insulin regulates blood glucose, and testosterone governs male secondary sexual characters — none of them directly controls heart rate.