| division | 1. The act of dividing. 2. <zoology> A rank that if treated as a division of a genus or subgenus is deemed to be of subgeneric rank for the purposes of nomenclature. 3. A taxon at the rank of division. The second highest taxonomic classification for the kingdoms Plantae (plants) and Fungi, between kingdom level and class level. (09 Jan 1998) |
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| division septum | <cell biology> The cell wall that forms between daughter cells at the end of mitosis in plant cells or just before separation in bacteria. (18 Nov 1997) |
| indirect nuclear division | <cell biology> A method of indirect division of a cell, consisting of a complex of various processes, by means of which the two daughter nuclei normally receive identical complements of the number of chromosomes characteristic of the somatic cells of the species. Mitosis, the process by which the body grows and replaces cells, is divided into four phases. 1. Prophase: formation of paired chromosomes, disappearance of nuclear membrane, appearance of the achromatic spindle, formation of polar bodies. 2. Metaphase: arrangement of chromosomes in the equatorial plane of the central spindle to form the monaster. Chromosomes separate into exactly similar halves. 3. Anaphase: the two groups of daughter chromosomes separate and move along the fibres of the central spindle, each toward one of the asters, forming the diaster. 4. Telophase: the daughter chromosomes resolve themselves into a reticulum and the daughter nuclei are formed, the cytoplasm divides, forming two complete daughter cells. NOTE: the term mitosis is used interchangeably with cell division, but strictly speaking it refers to nuclear division, whereas cytokinesis refers to division of the cytoplasm. In some cells, as in many fungi and the fertilized eggs of many insects, nuclear division occurs within the cell unaccompanied by division of the cytoplasm and formation of daughter cells. (13 Nov 1997) |
| equatorial division | Nuclear division in which each chromosome divides equally. (05 Mar 2000) |
| first meiotic division | The first of two consecutive divisions of the nucleus of an eukaryotic cell during the process of meiosis. It includes the following stages of meiosis: prophase I, metaphase I, anaphase I, and telophase I. (09 Oct 1997) |
| basal lamina of cochlear | A thin layer of tissue covered with mesothelial cells that separates the cochlea from the scala tympani in the ear. (18 Nov 1997) |
| basilar crest of cochlear duct | An inward projection of the spiral ligament of the cochlea to which is attached the basilar membrane forming the floor of the cochlear duct. Synonym: crista basilaris ductus cochlearis. (05 Mar 2000) |
| vein of cochlear aqueduct | It drains the cochlea, sacculus, and part of the utricules, and empties into the superior bulb of the jugular vein by accompanying the perilymphatic duct through the cochlear canaliculus. Synonym: vena aqueductus cochleae, vein of cochlear aqueduct, vena canaliculi cochleae. (05 Mar 2000) |
| vein of cochlear canaliculus | It drains the cochlea, sacculus, and part of the utricules, and empties into the superior bulb of the jugular vein by accompanying the perilymphatic duct through the cochlear canaliculus. Synonym: vena aqueductus cochleae, vein of cochlear aqueduct, vena canaliculi cochleae. (05 Mar 2000) |
| vestibular caecum of the cochlear duct | <anatomy> The lower extremity of the cochlear duct, occupying the cochlear recess in the vestibule. Synonym: caecum vestibulare, vestibular blind sac. (05 Mar 2000) |
| vestibular wall of cochlear duct | The membrane separating the cochlear duct from the vestibular canal; it consists of squamous epithelial cells with microvilli toward the ductus, a basement membrane, and a thin layer of connective tissue toward the scala. Synonym: membrana vestibularis, paries vestibularis ductus cochlearis, Reissner's membrane, vestibular wall of cochlear duct. (05 Mar 2000) |
| Reichert's cochlear recess | A small depression on the inner wall of the vestibule of the labyrinth at the portion of the pyramid of vestibule, between the two limbs into which the vestibular crest divides posteriorly; it is perforated by foramina giving passage to fibres which the cochlear branch of the vestibulocochlear nerve sends to the posterior extremity of the cochlear duct. Synonym: recessus cochlearis, Reichert's cochlear recess. (05 Mar 2000) |
| cochlear | <anatomy> Of or pertaining to the cochlea. (18 Nov 1997) |
| cochlear aqueduct | A channel containing perilymph passing through the temporal bone, connecting the scala tympani of the cochlea to the subarachnoid space. (12 Dec 1998) |
| cochlear area | The area inferior to the transverse crest of the fundus of the internal acoustic meatus through which the filaments of the cochlear nerve pass to enter the cochlea; forms the base of the cone-shaped modiolus about which the cochlear canal spirals. See: base of modiolus. Synonym: area cochleae. (05 Mar 2000) |