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breast cancer

(Encyclopedia)breast cancer, cancer that originates in the breast. Breast cancer is the second leading cause of cancer death in women (following lung cancer). Although the vast majority of the cases occur in women,...

gall bladder

(Encyclopedia)CE5 Gall bladder gall bladder, small pear-shaped sac that stores and concentrates bile. It is connected to the liver (which produces the bile) by the hepatic duct. When food containing fat reaches...

glucagon

(Encyclopedia)glucagon glo͞oˈkəgŏn [key], hormone secreted by the α cells of the islets of Langerhans, specific groups of cells in the pancreas. It tends to counteract the action of insulin, i.e., it raises th...

tetany

(Encyclopedia)tetany tĕtˈənē [key], condition of mineral imbalance in the body that results in severe muscle spasms. Tetany occurs when the concentration of calcium ions (Ca++) in extracellular fluids such as p...

kinetin

(Encyclopedia)kinetin kīˈnətĭn [key], one of a group of chemically similar plant hormones, the cytokinins, that promote cell division. In some instances kinetin acts together with another hormone, indoleacetic ...

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...

aging

(Encyclopedia)aging, in biology, cumulative changes in an organism, organ, tissue, or cell leading to a decrease in functional capacity. In humans, aging is associated with degenerative changes in the skin, bones, ...

insulin

(Encyclopedia)insulin, hormone secreted by the β cells of the islets of Langerhans, specific groups of cells in the pancreas. Insufficiency of insulin in the body results in diabetes. Insulin was one of the first ...

intrauterine device

(Encyclopedia)intrauterine device (IUD), variously shaped birth control device, usually of plastic, which is inserted into the uterus by a physician. The IUD may contain copper or levonorgestrel, a progestin (a hor...

pancreas

(Encyclopedia)pancreas pănˈkrēəs [key], glandular organ that secretes digestive enzymes and hormones. In humans, the pancreas is a yellowish organ about 7 in. (17.8 cm) long and 1.5 in. (3.8 cm) wide. It lies b...