What is a 'Z-Score'. A Z-score is a numerical measurement of a value's relationship to the mean in a group of values. If a Z-score is 0, it represents the score is identical to the mean score. Z-scores may also be positive or negative, with a positive value indicating the score is above the mean and a negative score indicating it is below the mean.
The pineal gland, also known as the pineal body, is an important endocrine gland that produces the hormone melatonin. Melatonin plays a key role in the sleep/wake cycle and the bodyâs response to sunlight. The pineal gland is a small, pinecone-shaped mass of glandular tissue about 1/3 of an inch (8 mm) long.
Melatonin is produced by the pineal gland and sends a signal to regulate the sleep-wake cycle in the sleep center of the brain. Interestingly, melatonin is also produced in the retina, the skin, and the GI tract, but this is not the melatonin what affects your biological sleep clock. This is the really important thing you should understand about melatonin: Melatonin is a sleep and body clock regulator â NOT a sleep initiator. Melatonin works with your biological clock by telling your brain when it is time to sleep.