sheath of Hertwig

sheath of Hertwig
sheath of Hert·wig -'hert-.vig n a two-layered epithelial wall that covers the developing root of a tooth, is derived from cells of the enamel organ, and later breaks up during the process of cement deposition called also Hertwig's sheath
Hert·wig 'hert-.vik Wilhelm August Oskar (1849-1922)
German embryologist and cytologist. Hertwig's important investigations concerned the nuclear transmission of hereditary characteristics, biogenetic theory, and the effect of radium rays on somatic and germ cells. He is most famous for being the first to recognize that the fusion of the nuclei of the sperm and ovum is the central event in fertilization. He also made the important observation that only one spermatozoan is required to fertilize one egg. With his brother, Richard von Hertwig, he studied the formation of the coelom and the theory of the germ layer.

Medical dictionary. 2011.

Игры ⚽ Поможем написать курсовую

Look at other dictionaries:

  • Hertwig sheath — sheath of Hertwig root s. (def. 1) …   Medical dictionary

  • Hertwig's sheath — Hert·wig s sheath hərt wigz , hert viks n SHEATH OF HERTWIG …   Medical dictionary

  • Hertwig's epithelial root sheath — The Hertwig s epithelial root sheath (frequently abbreviated as HERS ) is a proliferation of epithelial cells located at the cervical loop of the enamel organ in a developing tooth. Hertwig s epithelial root sheath initates the formation of… …   Wikipedia

  • Hertwig sheath — Hert·wig sheath (hertґvik) [Richard Carl Wilhelm Theodor von Hertwig, German zoologist, 1850–1937] root sheath (def. 1) …   Medical dictionary

  • sheath — 1. Any enveloping structure, such as the membranous covering of a muscle, nerve, or blood vessel. Any sheathlike structure. SYN: vagina (1). 2. The prepuce of male animals, especially of the horse. 3. A specially designed tu …   Medical dictionary

  • Hertwig — Wilhelm A.O., German embryologist, 1849–1922. See H. sheath. Richard, German zoologist, 1850–1937. See Magendie H. sign, Magendie H. syndrome …   Medical dictionary

  • Gaine épithéliale de Hertwig — Fichier:HERS.png (1) GEH, (2) restes cellulaires épitheliaux de Malassez, (3) follicule dentaire, (4) céementoblastes, (5) ligament alvéolo dentaire, (6) cellules alveolaires, (7) os, (8) odontoblastes. La gaine épithéliale de Hertwig (GEH) ou… …   Wikipédia en Français

  • root sheath — n the epidermal lining of a hair follicle * * * 1. an epithelial extension of the cervical loop of the enamel organ, consisting of the inner and outer enamel epithelium, and directing the number and morphological growth of the roots. It is… …   Medical dictionary

  • epithelial diaphragm — an epithelial structure, evolving from the root sheath (sheath of Hertwig), that narrows the opening into the pulp chamber, diminishing its caliber. It is in close contact with the bone forming the fundus of the developing alveolus, from which it …   Medical dictionary

  • Tooth development — Radiograph of lower right (from left to right) third, second, and first molars in different stages of development. Tooth development or odontogenesis is the complex process by which teeth form from embryonic cells, grow, and erupt into the mouth …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”