Columbia Encyclopedia

Search results

500 results found

Huntington's disease

(Encyclopedia)Huntington's disease, hereditary, acute disturbance of the central nervous system usually beginning in middle age and characterized by involuntary muscular movements and progressive intellectual deter...

Nemertinea

(Encyclopedia)CE5 A. Ribbon worm, representative of the phylum Nemertinea B. Internal anatomy of a ribbon worm Nemertinea nĕmərtĭnˈēə [key], phylum of elongated, often flattened, marine Worms, sometimes c...

intoxication

(Encyclopedia)intoxication, condition of body tissue affected by a poisonous substance. Poisonous materials, or toxins, are to be found in heavy metals such as lead and mercury, in drugs, in chemicals such as alcoh...

spinal puncture

(Encyclopedia)spinal puncture, surgical penetration of the spinal canal by a hollow needle introduced between two of the lumbar vertebrae. The arrangement permits injection of antibiotics or anesthetics (see anesth...

Charcot, Jean Martin

(Encyclopedia)Charcot, Jean Martin zhäN märtăNˈ shärkōˈ [key], 1825–93, French neurologist. At the Salpêtrière in Paris he developed the greatest clinic of his time for diseases of the nervous system. He...

nicotine

(Encyclopedia)nicotine, C10H14N2, poisonous, pale yellow, oily liquid alkaloid with a pungent odor and an acrid taste. It turns brown on exposure to air. Nicotine, a naturally occurring constituent of tobacco, is t...

brain stem

(Encyclopedia)brain stem, lower part of the brain, adjoining and structurally continuous with the spinal cord. The upper segment of the human brain stem, the pons, contains nerve fibers that connect the two halves ...

thyroxine

(Encyclopedia)thyroxine thīrŏkˈsēn [key], substance secreted by the thyroid gland. The hormone thyroxine forms by combining the amino acid tyrosine with iodine. Complexed to a protein, it is stored in the folli...

acetylcholine

(Encyclopedia)acetylcholine əsētˌəlkōˈlēn [key], a small organic molecule liberated at nerve endings as a neurotransmitter. It is particularly important in the stimulation of muscle tissue. The transmission ...

drug poisoning

(Encyclopedia)drug poisoning, toxic effects caused by an administered drug. Worldwide more than 9 million natural and synthetic chemicals have been identified; fewer than 3000 cause more than 95% of acidental and d...