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oxytocin

(Encyclopedia)oxytocin ŏksĭtōˈsĭn [key], hormone released from the posterior lobe of the pituitary gland that facilitates uterine contractions and the milk-ejection reflex. The structure of oxytocin, a cyclic ...

astatine

(Encyclopedia)astatine ăsˈtətēn, –tĭn [key] [Gr.,=unstable], semimetallic radioactive chemical element; symbol At; at. no. 85; at. wt. of most stable isotope 210; m.p. 302℃ (estimated); b.p. 337℃ (estima...

puberty

(Encyclopedia)puberty pyo͞oˈbərtē [key], period during which the onset of sexual maturity occurs. It usually takes place between the ages of 10 and 15 in both sexes but sometimes occurs as early as 7 or 8 years...

honey badger

(Encyclopedia)honey badger or ratel rātˈəl [key], carnivore, Mellivora capensis, of the forest and brush country of Africa, the Middle East, and India; it is a member of the badger and skunk family. Related to t...

atropine

(Encyclopedia)atropine ătˈrəpēn, –pĭn [key], alkaloid drug derived from belladonna and other plants of the family Solanaceae (nightshade family). Available either as the tincture or extract of belladonna, or...

Axelrod, Julius

(Encyclopedia)Axelrod, Julius ăkˈsəlrŏd [key], 1912–2004, American biochemist whose work was influential in the development of pharmaceuticals, b. New York City, grad. City College, N.Y. (B.S. 1933), New York...

adolescence

(Encyclopedia)adolescence, time of life from onset of puberty to full adulthood. The exact period of adolescence, which varies from person to person, falls approximately between the ages 12 and 20 and encompasses b...

progesterone

(Encyclopedia)progesterone prōjĕsˈtərōnˌ [key], female sex hormone that induces secretory changes in the lining of the uterus essential for successful implantation of a fertilized egg. A steroid, progesterone...

Rotifera

(Encyclopedia)Rotifera, phylum of predominantly free-living, microscopic, aquatic or semiterrestrial pseudocoelomates. Each rotifer has a head bearing a crown of cilia, the corona, at the anterior end; most rotifer...

salivary glands

(Encyclopedia)salivary glands sălˈəvârˌē [key], in humans, three pairs of glands that secrete the alkaline digestive fluid, saliva, into the mouth. Most animals have salivary glands that resemble those in hum...