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(Photo: TTO) |
In higher vertebrates, the biological clock is understood to consist of three components:
1. The retina (the neural network in the eye) which receives the day-night rhythm according to the light cycle over 24 hours.
2. SCN (suprachiasmatic nucleus) – a neural structure in the brain considered the master clock, signaling time through a subjectively regulated neural pathway.
3. The pineal gland, located between the two hemispheres of the brain, produces the hormone melatonin.
It can be said that melatonin (M) is the final product of the biological clock. It is synthesized from the amino acid tryptophan. In the human body, M is synthesized the most at night and significantly decreases during the day. The pineal gland in prepubescent children produces a high amount of M. M inhibits the development of the sexual glands.
Therefore, children who sleep little or sleep in bright light may experience early puberty and delayed growth. M is used to treat circadian rhythm disorders, alleviate jet lag, and improve sleep for the blind. In some countries, M is widely sold and regarded as a youth-preserving supplement.
Thanh Dat
