Hence, an arrow which bends less is said to have more spine. In order to strike consistently, a group of arrows must be similarly spined. Center-shot bows, in which the arrow passes through the central vertical axis of the bow riser, may obtain consistent results from arrows with a wide range of spines.
Definition of MELATONIN. : a vertebrate hormone that is derived from serotonin, is secreted by the pineal gland especially in response to darkness, and has been linked to the regulation of circadian rhythms.See melatonin defined for kids.ADVERTISEMENT. Greek melas black + -tonin (as in serotonin).efinition of MELATONIN. : a vertebrate hormone that is derived from serotonin, is secreted by the pineal gland especially in response to darkness, and has been linked to the regulation of circadian rhythms. See melatonin defined for kids. ADVERTISEMENT. Greek melas black + -tonin (as in serotonin).
Serotonin is a neurotransmitter found in your gastrointestinal tract, platelets and central nervous system. Tryptophan is a building block of serotonin as well as of melatonin. Tryptophan is an essential amino acid, meaning that you cannot synthesize it in your body, but must obtain it from dietary sources.In your central nervous system, serotonin helps to regulate mood, sleep and appetite.our pineal gland produces melatonin, and your intestinal cells and brainâs nervous center produces serotonin. Both melatonin and serotonin play several roles in human behavior and cognition. Serotonin syndrome is a medical condition defined as excess levels of serotonin in your body.