Melanin has many biological functions, including colouring the skin and hairs or feathers, strengthening plant cell walls and insect cuticle, absorbing light (and so providing photoreceptor shieldlng, thermoregulation, photoprotectlon), and it is an important free radical sink.
Medical Definition of autistic disorder. : autism Autistic disorder is classic autism, one of the more severe disorders on the spectrum. Persons with autistic disorder have substantial impairment in social skills, verbal communication, and cognitive and behavioral flexibility.âIsabelle Rapin , The New England Journal of Medicine, 1 Aug. 2002.
Definition. Bipolar disorder, also known as manic-depressive illness, is a brain disorder that causes unusual shifts in mood, energy, and ability to function. These are not the normal ups and downs; the symptoms of bipolar disorder are severe.eople with bipolar disorder may need help to get help: 1  Often people with bipolar disorder do not realize how impaired they are, or they blame their problems on some cause other than mental illness. 2  A person with bipolar disorder may need strong encouragement from family and friends to seek treatment.