![\"Quel](\"\/documents\/images\/histologie_articles\/ovaire\/lombric_cs_anterieure_ovaire_13-WEB.jpg\")
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Voir l’image de plus grande taille<\/a><\/p>\n <\/p>\n Voir l’image l\u00e9gend\u00e9e<\/a><\/p>\n <\/p>\n L’image de la semaine 12-2019 est issue de l’observation d’une coupe histologique \u00e0 l’objectif x40 du microscope photonique.<\/p>\n Elle comporte de multiples unit\u00e9s juxtapos\u00e9es, comprenant chacune une structure centrale circulaire ou ovale bien d\u00e9limit\u00e9e, entour\u00e9e d’une masse granuleuse p\u00e9riph\u00e9rique peu importante. Le noyau \u00e9tant volumineux par rapport au cytoplasme, le rapport nucl\u00e9oplasmique de ces cellules est \u00e9lev\u00e9.<\/p>\n <\/p>\n Les cellules pr\u00e9sentes dans l’organe diff\u00e8rent par l’organisation de leurs noyaux. Ils contiennent des taches sombres accol\u00e9es \u00e0 la face interne de l’enveloppe nucl\u00e9aire ou des filaments. Ces structures repr\u00e9sentent deux formes de la chromatine, en amas et condens\u00e9e en chromosomes. En l’occurrence, la pr\u00e9sence de filaments \u00e9pais dans certains noyaux sugg\u00e8re que les cellules qui les contiennent sont entr\u00e9es en prophase de premi\u00e8re division de m\u00e9iose<\/a>. Certaines cellules poss\u00e8dent en outre un cytoplasme relativement plus abondant.<\/p>\n <\/p>\n Entre les cellules germinales, des fibres sont pr\u00e9sentes ainsi que des cellules allong\u00e9es \u00e0 noyau finement ponctu\u00e9 et cytoplasme granuleux peu color\u00e9. <\/p>\n Il s’agit de tissu conjonctif<\/a> fibreux et de cellules somatiques, non reproductrices.<\/p>\n <\/p>\n L’organisation ainsi d\u00e9crite est caract\u00e9ristique d’un ovaire. En absence de cavit\u00e9 interne, il peut \u00eatre qualifi\u00e9 de plein.<\/p>\n Organe \u00e0 l’origine des gam\u00e8tes femelles ou ovules<\/a>, il est le si\u00e8ge de l’ovogen\u00e8se. Les cellules pr\u00e9sentes sont au d\u00e9but de leur \u00e9volution. Les cellules dont les noyaux comportent des amas de chromatine p\u00e9riph\u00e9riques sont des ovogonies, et les cellules dont les noyaux contiennent des chromosomes sont des ovocytes I ayant d\u00e9but\u00e9 la premi\u00e8re division de m\u00e9iose. <\/p>\n Pour en savoir plus, consulter :<\/p>\n • <\/span>les pages Premiers pas histologiques<\/a> de Codex virtualis (adresse : http:\/\/codexvirtualis.fr\/codex\/de-lorganisation-interne\/premiers-pas-histologiques)<\/p>\n • <\/span>Burkitt H.G., Young B., Heath J.W., 1993 \u2013 Histologie fonctionnelle Wheater. Arnette, 408p. Paris<\/p>\n • <\/span>Gorgees N. S. and Khalid V. A., 2017 – Histomorphology of the ovaries of the earthworm, Dendrobaena atheca<\/em> Cernosvitov (Annelida, Clitellata: Oligochaeta)<\/a>. Journal of Morphological Science, 34, 3 : 178-185 (adresse : https:\/\/www.thieme-connect.de\/products\/ejournals\/abstract\/10.4322\/jms.117817) • <\/span>Heusser S., Dupuy H.G., 2015 \u2013 Atlas biologie animale. Dunod, 220p. Paris<\/p>\n • <\/span>Leake L. D., 1975 \u2013 Comparative histology, an introduction to the microscopic structure of animals. Academic press, 738p. London, New York, San Francisco<\/p>\n • <\/span>Siekierska E., 2003 – The structure of the ovary and oogenesis in the earthworm, Dendrobaena veneta<\/em> (Annelida, Clitellata)<\/a>. Tissue & Cell, 35 : 252\u2013259 <\/p>\n Une citation \u00ab\u00a0Il suivait son id\u00e9e. C’\u00e9tait une id\u00e9e fixe et il \u00e9tait surpris de ne pas avancer.\u00a0\u00bb J. Pr\u00e9vert Une image Voir l’image de plus grande taille Voir l’image l\u00e9gend\u00e9e L’image de la semaine 12-2019 est issue de l’observation d’une coupe histologique \u00e0 l’objectif x40 du microscope photonique. Elle comporte […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[1],"tags":[47,14,23,22],"class_list":["post-11879","post","type-post","status-publish","format-standard","hentry","category-a-la-une","tag-annelide","tag-histologie","tag-observation","tag-physiologie"],"aioseo_notices":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/posts\/11879","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/comments?post=11879"}],"version-history":[{"count":11,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/posts\/11879\/revisions"}],"predecessor-version":[{"id":11883,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/posts\/11879\/revisions\/11883"}],"wp:attachment":[{"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/media?parent=11879"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/categories?post=11879"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/tags?post=11879"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\nLa structure centrale contient des amas sombres p\u00e9riph\u00e9riques ou des filaments d’\u00e9paisseur variable ainsi qu’un fond p\u00e2le.
\nIl s’agit d’un noyau, entour\u00e9 d’un <\/a>cytoplasme<\/a>, l’ensemble correspondant \u00e0 une cellule<\/a> animale.<\/p>\n
\nElles r\u00e9v\u00e8lent que les cellules sont \u00e0 diff\u00e9rents stades d’une \u00e9volution nucl\u00e9aire.<\/p>\n
\nL’organe correspond vraisemblablement \u00e0 une gonade<\/a> au sein de laquelle des cellules germinales<\/a> \u00e9voluent en gam\u00e8tes<\/a>, processus appel\u00e9 gam\u00e9togen\u00e8se<\/a>.<\/p>\n
\nSch\u00e9matiquement, les cellules germinales appel\u00e9es ovogonies, par division mitotique, donnent naissance \u00e0 des ovocytes I qui effectuent la premi\u00e8re division de m\u00e9iose. Elles produisent des cellules filles d\u00e9sign\u00e9es par le terme ovocytes II qui subissent la deuxi\u00e8me division de m\u00e9iose et conduisent \u00e0 des ovotides.
\nParall\u00e8lement \u00e0 cette \u00e9volution nucl\u00e9aire, une \u00e9volution cytoplasmique intervient, avec l’accumulation de r\u00e9serves constituant le vitellus, g\u00e9n\u00e9ralement d\u00e9pos\u00e9 au stade ovocyte I.<\/p>\n
\nEn l’occurrence, il s’agit d’un ovaire de Lombric, Ann\u00e9lide<\/a> oligoch\u00e8te, dont l’organisation g\u00e9n\u00e9rale a fait l’objet de l’article de la semaine 10-2019<\/a> de Codex virtualis, et les ovocytes I en vitellogen\u00e8se de celui de la semaine 11-2019<\/a>.<\/p>\n
\nDOI : 10.4322\/jms.117817<\/a><\/p>\n
\nDOI : 10.1016\/S0040-8166(03)00038-7<\/a><\/p>\n
\n","protected":false},"excerpt":{"rendered":"