Segmentation cavity

Segmentation cavity
Segmentation Seg`men*ta"tion, n. The act or process of dividing into segments; specifically (Biol.), a self-division into segments as a result of growth; cell cleavage; cell multiplication; endogenous cell formation. [1913 Webster]

{Segmentation cavity} (Biol.), the cavity formed by the arrangement of the cells in segmentation or cleavage of the ovum; the cavity of the blastosphere. In the gastrula stage, the segmentation cavity in which the mesoblast is formed lies between the entoblast and ectoblast. See Illust. of {Invagination}.

{Segmentation nucleus} (Biol.), the body formed by fusion of the male and female pronucleus in an impregnated ovum. See the Note under {Pronucleus}.

{Segmentation of the ovum}, or {Egg cleavage} (Biol.), the process by which the embryos of all the higher plants and animals are derived from the germ cell. In the simplest case, that of small ova destitute of food yolk, the ovum or egg divides into two similar halves or segments (blastomeres), each of these again divides into two, and so on, thus giving rise to a mass of cells (mulberry mass, or morula), all equal and similar, from the growth and development of which the future animal is to be formed. This constitutes {regular segmentation}. Quite frequently, however, the equality and regularity of cleavage is interfered with by the presence of food yolk, from which results unequal segmentation. See {Holoblastic}, {Meroblastic}, {Alecithal}, {Centrolecithal}, {Ectolecithal}, and {Ovum}.

{Segmentation sphere} (Biol.), the blastosphere, or morula. See {Morula}. [1913 Webster]


The Collaborative International Dictionary of English. 2000.

Игры ⚽ Поможем написать курсовую

Look at other dictionaries:

  • segmentation cavity — n BLASTOCOEL * * * blastocoele …   Medical dictionary

  • segmentation cavity — n. BLASTOCOELE …   English World dictionary

  • segmentation cavity — blastocoel lastocoel, Blastocoele Blas to*c[oe]le blastocoele lastocoele, n. [Gr. blasto s sprout + koi^los hollow.] (Biol.) The cavity inside a blastula; also called {segmentation cavity}. [1913 Webster] …   The Collaborative International Dictionary of English

  • segmentation cavity — noun the fluid filled cavity inside a blastula • Syn: ↑blastocoel, ↑blastocoele, ↑blastocele, ↑cleavage cavity • Derivationally related forms: ↑blastocoelic (for: ↑blastocele), ↑ …   Useful english dictionary

  • segmentation cavity — noun Date: 1883 blastocoel …   New Collegiate Dictionary

  • segmentation cavity — see blastocoel …   Dictionary of invertebrate zoology

  • segmentation cavity — Embryol. blastocoele. [1885 90] * * * …   Universalium

  • segmentation cavity — /sɛgmənˈteɪʃən kævəti/ (say segmuhn tayshuhn kavuhtee) noun a blastocoel; the hollow of a blastula …  

  • Segmentation — Seg men*ta tion, n. The act or process of dividing into segments; specifically (Biol.), a self division into segments as a result of growth; cell cleavage; cell multiplication; endogenous cell formation. [1913 Webster] {Segmentation cavity} (Biol …   The Collaborative International Dictionary of English

  • Segmentation nucleus — Segmentation Seg men*ta tion, n. The act or process of dividing into segments; specifically (Biol.), a self division into segments as a result of growth; cell cleavage; cell multiplication; endogenous cell formation. [1913 Webster] {Segmentation… …   The Collaborative International Dictionary of English

Share the article and excerpts

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