| slovo | definícia |
ovum
(encz) | ovum,vajíčko n: Zdeněk Brož |
Ovum
(gcide) | Ovum \O"vum\ ([=o]"v[u^]m), n.; pl. L. Ova ([=o]"v[.a]), E.
Ovums ([=o]"v[u^]mz). [L., an egg. See Oval.]
1. (Biol.) A more or less spherical and transparent cell,
which by a process of multiplication and growth develops
into a mass of cells, constituting a new individual like
the parent; an egg, spore, germ, or germ cell. See Illust.
of Mycropyle.
[1913 Webster]
Note: The ovum is a typical cell, with a cell wall, cell
substance, nucleus, and nucleolus. In man and the
higher animals the cell wall, a vertically striated
membrane, is called the zona pellucida; the cell
contents, the vitellus; the nucleus, the germinal
vesicle; and the nucleolus, the germinal spot. The
diameter of the ripe ovum in man and the domestic
animals varies between 1-200 and 1-120 of an inch.
[1913 Webster]
2. (Arch.) One of the series of egg-shaped ornaments into
which the ovolo is often carved. --Gwilt.
[1913 Webster] |
ovum
(wn) | ovum
n 1: the female reproductive cell; the female gamete [syn:
ovum, egg cell] |
| | podobné slovo | definícia |
fertilized ovum
(encz) | fertilized ovum, n: |
ovum
(encz) | ovum,vajíčko n: Zdeněk Brož |
Novum
(gcide) | Novum \No"vum\, n.
A game at dice, properly called novem quinque (L., nine
five), the two principal throws being nine and five. [Obs.]
--Shak.
[1913 Webster] |
Ovums
(gcide) | Ovum \O"vum\ ([=o]"v[u^]m), n.; pl. L. Ova ([=o]"v[.a]), E.
Ovums ([=o]"v[u^]mz). [L., an egg. See Oval.]
1. (Biol.) A more or less spherical and transparent cell,
which by a process of multiplication and growth develops
into a mass of cells, constituting a new individual like
the parent; an egg, spore, germ, or germ cell. See Illust.
of Mycropyle.
[1913 Webster]
Note: The ovum is a typical cell, with a cell wall, cell
substance, nucleus, and nucleolus. In man and the
higher animals the cell wall, a vertically striated
membrane, is called the zona pellucida; the cell
contents, the vitellus; the nucleus, the germinal
vesicle; and the nucleolus, the germinal spot. The
diameter of the ripe ovum in man and the domestic
animals varies between 1-200 and 1-120 of an inch.
[1913 Webster]
2. (Arch.) One of the series of egg-shaped ornaments into
which the ovolo is often carved. --Gwilt.
[1913 Webster] |
Pseudovum
(gcide) | Pseudovum \Pseu*do"vum\, n.; pl. Pseudova. [NL. See Pseudo-,
and Ovum.] (Zool.)
An egglike germ produced by the agamic females of some
insects and other animals, and by the larv[ae] of certain
insects. It is capable of development without fertilization.
See Illust. of P[ae]dogenesis.
[1913 Webster] |
Segmentation of the ovum
(gcide) | 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] |
Tritovum
(gcide) | Tritovum \Tri*to"vum\, n.; pl. Tritova. [NL., fr. Gr. ? third
+ L. ovum egg.] (Zool.)
An embryonic insect which has twice cast its skin previous to
hatching from the egg.
[1913 Webster] |
fertilized ovum
(wn) | fertilized ovum
n 1: (genetics) the diploid cell resulting from the union of a
haploid spermatozoon and ovum (including the organism that
develops from that cell) [syn: zygote, fertilized ovum] |
ovum
(wn) | ovum
n 1: the female reproductive cell; the female gamete [syn:
ovum, egg cell] |
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