A mid ocean ridge is made by a divergent boundary. The mid-ocean ridges of the world are connected and form a single global mid-oceanic ridge system that is part of every ocean. The mid-oceanic ridge system is the longest mountain range in the world. The continuous mountain range is 65,000 km (40,400 mi) long.
Circadian rhythms are important in determining human sleep patterns. The body's master clock, or SCN, controls the production of melatonin, a hormone that makes you sleepy. Since it is located just above the optic nerves, which relay information from the eyes to the brain, the SCN receives information about incoming light.
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.