IB Biology: C3.1-Melatonin and Sleep Patterns

Front

What is the circadian rhythm?

Back

The circadian rhythm is a 24-hour cycle in human behavior or physiology that aligns with the day-night cycle.

Front

What is the most obvious pattern of the circadian rhythm?

Back

The sleep and wake cycle.

Front

Which brain regions regulate the circadian rhythm?

Back

The hypothalamus and the pineal gland.

Front

What is the role of the suprachiasmatic nuclei (SCN)?

Back

The SCN relays light exposure information from the retina to the hypothalamus, which then passes it to the pineal gland.

Front

How does the pineal gland adjust melatonin concentrations?

Back

The pineal gland adjusts melatonin concentrations by refraining from releasing melatonin during the day and enhancing secretion in darkness.

Front

What effect does bright light have on melatonin secretion?

Back

Bright light suppresses melatonin secretion.

Front

What are the effects of melatonin on the body?

Back

Melatonin causes the core body temperature to drop, decreases urine production, and increases sleepiness.

Front

What happens to melatonin secretion over time?

Back

Melatonin secretion becomes entrained to anticipate darkness and daylight.

Front

What causes 'jet lag'?

Back

Jet lag is caused by the body's inability to adjust to a new time zone after traveling through several time zones.