diaphragm


diaphragm
/duy"euh fram'/, n.
1. Anat.
a. a muscular, membranous or ligamentous wall separating two cavities or limiting a cavity.
b. the partition separating the thoracic cavity from the abdominal cavity in mammals.
2. Physical Chem.
a. a porous plate separating two liquids, as in a galvanic cell.
b. a semipermeable membrane.
3. a thin disk that vibrates when receiving or producing sound waves, as in a telephone, microphone, speaker, or the like.
4. Also called pessary. a thin, dome-shaped device, usually of rubber, for wearing over the uterine cervix during sexual intercourse to prevent conception.
5. a plate with a hole in the center or a ring that is placed on the axis of an optical instrument, as a camera, and that controls the amount of light entering the instrument.
6. a plate or web for stiffening metal-framed constructions.
v.t.
7. to furnish with a diaphragm.
8. to reduce the aperture of (a lens, camera, etc.) by means of a diaphragm.
[1350-1400; ME diafragma < LL diaphragma < Gk diáphragma the diaphragm, midriff, equiv. to dia- DIA- + phrágma a fence]

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Dome-shaped muscular and membranous structure between the thoracic and abdominal cavities.

The principal muscle used in respiration, it is also important in coughing, vomiting, excretion, and other expulsive functions. Spasms of the diaphragm produce hiccups. The aorta passes behind the diaphragm; the inferior vena cava and esophagus pass through it. Protrusion of part of the stomach above the diaphragm is called a hiatal hernia.

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 dome-shaped, muscular and membranous structure that separates the thoracic (chest) and abdominal cavities in mammals; it is the principal muscle of respiration.

      The muscles of the diaphragm arise from the lower part of the sternum (breastbone), the lower six ribs, and the lumbar (loin) vertebrae of the spine and are attached to a central membranous tendon. Contraction of the diaphragm increases the internal height of the thoracic cavity, thus lowering its internal pressure and causing inspiration of air. Relaxation of the diaphragm and the natural elasticity of lung tissue and the thoracic cage produce expiration. The diaphragm is also important in expulsive actions—e.g., coughing, sneezing, vomiting, crying, and expelling feces, urine, and, in parturition, the fetus. The diaphragm is pierced by many structures, notably the esophagus, aorta, and inferior vena cava, and is occasionally subject to herniation (rupture). Small holes in the membranous portion of the diaphragm sometimes allow abnormal accumulations of fluid or air to move from the abdominal cavity (where pressure is positive during inspiration) into the pleural spaces of the chest (where pressure is negative during inspiration). Spasmodic inspiratory movement of the diaphragm produces the characteristic sound known as hiccupping (hiccup).

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Universalium. 2010.

Synonyms:

Look at other dictionaries:

  • Diaphragm — Di a*phragm, n. [L. diaphragma, Gr. ?, fr. ? to fence by a partition wall; dia through + ?, ?, to fence, inclose; prob. akin to L. fareire to stuff: cf. F. diaphragme. See {Farce}.] 1. A dividing membrane or thin partition, commonly with an… …   The Collaborative International Dictionary of English

  • Diaphragm — Diaphragm. См. Диафрагма. (Источник: «Металлы и сплавы. Справочник.» Под редакцией Ю.П. Солнцева; НПО Профессионал , НПО Мир и семья ; Санкт Петербург, 2003 г.) …   Словарь металлургических терминов

  • diaphragm — late 14c., from L.L. diaphragma, from Gk. diaphragma partition, barrier, muscle which divides the thorax from the abdomen, from diaphrassein to barricade, from dia across (see DIA (Cf. dia )) + phrassein to fence or hedge in. The native word is… …   Etymology dictionary

  • diaphragm — ► NOUN 1) a dome shaped muscular partition separating the thorax from the abdomen in mammals. 2) a taut flexible membrane in mechanical or acoustic systems. 3) a thin contraceptive cap fitting over the cervix. 4) a device for varying the… …   English terms dictionary

  • diaphragm — [dī′ə fram΄] n. [ME diafragma < LL diaphragma < Gr < dia , through + phragma, a fence < phrassein, to enclose] 1. the partition of muscles and tendons between the chest cavity and the abdominal cavity; midriff: see LUNG 2. a) any… …   English World dictionary

  • Diaphragm — Contents 1 Optics and photography 2 Acoustics 3 Other 4 …   Wikipedia

  • diaphragm — 1. The musculomembranous partition between the abdominal and thoracic cavities. SYN: diaphragma (2) [TA], interseptum, midriff, phren (1). 2. A thin disk pierced with an opening, used in a microscope, camera, or other op …   Medical dictionary

  • diaphragm — n. 1) (in anatomy) a thin musculomembranous dome shaped muscle that separates the thoracic and abdominal cavities. The diaphragm is attached to the lower ribs at each side and to the breastbone and the backbone at the front and back. It bulges… …   The new mediacal dictionary

  • diaphragm — 1. noun /ˈdaɪəˌfræm/ a) In mammals, a sheet of muscle separating the thorax from the abdomen, contracted and relaxed in respiration to draw air into and expel air from the lungs; also called thoracic diaphragm. b) Any of various membranes or… …   Wiktionary

  • diaphragm — n. contraceptive device to insert a diaphragm * * * [ daɪəfræm] [ contraceptive device ] to insert a diaphragm …   Combinatory dictionary


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