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 of BIPOLAR DISORDER. : any of several psychological disorders of mood characterized usually by alternating episodes of depression and mania âcalled also manic depression, manic-depressive illness.See bipolar disorder defined for English-language learners.ADVERTISEMENT. any of several psychological disorders of mood characterized usually by alternating episodes of depression and mania âcalled also manic depression, manic-depressive illness. See bipolar disorder defined for English-language learners.