Answer:
Melatonin is released by the pineal gland, that is hormones or neurotransmitter which is related to the sleep. It is influence the sleep wake cycle. Where as melanin is pigment that naturally colors skin or the hair. More the melanin more the darker the skin or hair.
Melatonin regulates changing in pigmentation by association of melanin into the melanocytes within the skin, leads to the skin to color change. This relation is is also accountable for the yellowish skin color in elderly people and people with insomnia.
Answer:
The correct option is d. All of the above contribute to the pinal gland being called the body's timekeeper.
Explanation:
The pineal gland is a reddish-grey pine-cone shape gland present in the brain. It is responsible for the production of melatonin. The melatonin is a hormone which controls the body's sleep cycle and the circadian rhythm.
The melatonin production is stimulated by darkness. Therefore, the melatonin levels are low during the days and increases at night. This helps in regulating the body's sleep cycle and the circadian rhythm.
Thus, the pineal gland is referred to as the body's timekeeper.
