Which part of the human brain regulates the circadian rhythm?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. Hypothalamus.
The suprachiasmatic nucleus (SCN), located within the hypothalamus of the brain, is the master regulator of the human circadian rhythm. This small cluster of nerve cells receives direct input from the eyes regarding light levels to synchronize the body's ~24-hour sleep-wake cycle.
Key details regarding this regulation:
- Location: The SCN is in the hypothalamus, just above the optic chiasm.
- Function: It acts as the "master clock," coordinating peripheral clocks throughout the body.
- Light Sensitivity: The SCN receives information about light from the retina, which allows it to adjust the body's clock to the external environment.
- Melatonin Regulation: The SCN signals the pineal gland to produce melatonin when it is dark to promote sleep.
- Disruption: Damage to the SCN can cause a complete loss of the sleep-wake rhythm.