Back to TopCauses. Injury or surgery involving the leg, ankle, or foot can cause swelling. Swelling may also occur after pelvic surgery, especially for cancer. Long airplane flights or car rides, as well as standing for long periods of time, often lead to some swelling in the feet and ankles.
Medical Definition of Serotonin. Serotonin: A neurotransmitter that is involved in the transmission of nerve impulses. Serotonin can trigger the release of substances in the blood vessels of the brain that in turn cause the pain of migraine. Serotonin is also key to mood regulation; pain perception; gastrointestinal function, including perception of hunger and satiety; and other physical functions.
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.