Briefly summarize what is known about our biological clocks and their relationship to sleep

What will be an ideal response?

Humans and other animals operate on a 24-hour biological cycle. These daily cycles are particularly important in the regulation of sleep, but also in the regulation of temperature, urine production, hormonal secretions, and other bodily processes.

Circadian rhythms vary from person to person, and different people may have different optimal times to fall asleep, have a good night's sleep, etc.

The pathway for regulation of the human biological clock appears to be based on light levels, which go from the eye to an area of the brain called the suprachiasmatic nucleus (in the hypothalamus). This nucleus tells the pineal gland to secrete melatonin, a hormone that adjusts biological clocks.