Question

Hank Greene, an airline pilot, is having difficulty with the sleep-wakefulness portions of his circadian cycle. The pineal gland secretes the hormone , which influences this cycle.

Answer 1

Answer:

Melatonin

Explanation:

• Melatonin is the hormone that is produced by the pineal gland in response to the dark and light cycle.
• The pineal gland is turned on when there is darkness and turned off when there is light.
• When it's dark, the pineal gland becomes active and produces melatonin leading to an increase in the melatonin levels in the blood and a person starts to feel more sleepy and the levels of melatonin remain in the blood for about 12 hours after which they fall and the state of wakefulness occurs.
• The levels of melatonin fall sharply in the presence of bright light.
• Thus, the melatonin hormone is responsible for controlling the sleep-wake cycle.