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 one of many neurotransmitters found in the brain. It is also found in the blood, mucous membranes which line the digestive tract, and stomach. Serotonin is a chemical neurotransmitter made from tryptophan, an amino acid found in food.Certain imbalances in the brain's neurotransmitters are correlated to depression. Having higher levels of serotonin is shown to counter some depressive symptoms.erotonin is one of many neurotransmitters found in the brain. It is also found in the blood, mucous membranes which line the digestive tract, and stomach. Serotonin is a chemical neurotransmitter made from tryptophan, an amino acid found in food.