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.
1 Islet cells in the pancreas: Cells in the pancreas control the release of the hormones insulin and glucagon. 2  Parathyroid: Four tiny glands in the neck that play a role in bone development. 3  Pineal gland: A gland found near the center of the brain that may be linked to sleep patterns.