Question: What part in the brain is responsible for making a person feel sleepy?

Jacquie Oliwa answered on 4 Jul 2017:

Hi there..
Normally, sleep is regulated by exposure to light or to darkness. Exposure to light stimulates a nerve pathway from the retina in the eye to an area in the brain called the hypothalamus. There, a special center called the suprachiasmatic nucleus sends signals to other parts of the brain that control hormones, body temperature and other functions that play a role in making us feel sleepy or wide awake.

The suprachiasmatic nucleus works like a clock. Once exposed to the first light each day, the clock begins performing functions like raising body temperature and releasing stimulating hormones like cortisol which ensure you wake up and start to function..

It delays the release of other hormones like melatonin, which is associated with sleep onset, until hours later when darkness arrives. Melatonin is a natural hormone made by your body’s pineal gland (a pea-sized and located just above the middle of the brain).

During the day the pineal is inactive. When the sun goes down and darkness occurs, the pineal is “turned on” by the suprachiasmatic nucleus and begins to actively produce melatonin, which is released into the blood. Usually, this occurs around 9 pm. As a result, melatonin levels in the blood rise sharply and you begin to feel less alert. Sleep becomes more inviting. Melatonin levels in the blood stay elevated for about 12 hours – all through the night – before the light of a new day when they fall back to low daytime levels by about 9 am.

I hope that answers your question!
Best wishes,
Jacquie