![\"Quel](\"\/documents\/images\/histologie_articles\/ovaire\/lombric_cs_anterieure_ovaire_14-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 11-2019 provient de l’observation d’une coupe histologique \u00e0 l’objectif x40 du microscope photonique.<\/p>\n Elle repr\u00e9sente un organe dense d\u00e9pourvu de cavit\u00e9, et constitu\u00e9 d’unit\u00e9s ovo\u00efdes de dimensions diverses. <\/p>\n La cellule centrale comporte un noyau dans lequel un nucl\u00e9ole est visible ainsi que des filaments \u00e9pais correspondants \u00e0 des chromosomes. De grande taille, elle comprend un cytoplasme<\/a> abondant dans lequel de nombreux granules sont pr\u00e9sents. Certains sont fins alors que d’autres sont tr\u00e8s volumineux. Une telle organisation sugg\u00e8re qu’il s’agit d’une cellule germinale<\/a> femelle : les chromosomes individualis\u00e9s sont caract\u00e9ristiques des cellules en cours de division, et le cytoplasme granuleux abondant est rencontr\u00e9 dans les cellules accumulant des r\u00e9serves comme le vitellus. Des cellules de dimensions r\u00e9duites, dont le noyau contient des chromosomes mais dont le cytoplasme est peu abondant, sont \u00e9galement pr\u00e9sentes. <\/p>\n Enfin, des cellules l\u00e9g\u00e8rement allong\u00e9es sont associ\u00e9es aux ovocytes. Elles poss\u00e8dent un noyau ovale, muni d’un nucl\u00e9ole excentr\u00e9 et de chromatine en amas et en r\u00e9seau. Elles constituent des cha\u00eenes associ\u00e9es aux ovocytes I. <\/p>\n L’organe ainsi d\u00e9crit, au sein duquel est r\u00e9alis\u00e9e la formation des cellules sexuelles femelles ou ovogen\u00e8se, correspond \u00e0 un ovaire. Son organisation, avec des ovocytes I en cours de vitellogen\u00e8se et des trophocytes, sugg\u00e8re qu’il appartient \u00e0 un animal ovipare<\/a>.<\/p>\n En l’occurrence, il s’agit d’un ovaire de Lombric, Ann\u00e9lide<\/a> oligoch\u00e8te, dont la situation et la structure g\u00e9n\u00e9rale sont d\u00e9crites dans l’article de la semaine 10-2019<\/a> de Codex virtualis.<\/p>\n <\/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\u00a0Le sang s’h\u00e9rite et la vertu s’acquiert, et la vertu vaut par elle seule ce que le sang ne peut valoir.\u00a0\u00bb M. de Cervantes Une image Voir l’image de plus grande taille Voir l’image l\u00e9gend\u00e9e L’image de la semaine 11-2019 provient de l’observation d’une coupe histologique \u00e0 l’objectif x40 […]<\/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":"","jetpack_post_was_ever_published":false},"categories":[1],"tags":[47,14,23,22],"class_list":["post-11851","post","type-post","status-publish","format-standard","hentry","category-a-la-une","tag-annelide","tag-histologie","tag-observation","tag-physiologie"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\t
\nChacune comporte une sous-unit\u00e9 circulaire dans laquelle des structures granuleuses ou filamenteuses sont pr\u00e9sentes.
\nIl s’agit de <\/a>cellules<\/a> animales contenant un noyau.<\/p>\n
\nElle est entour\u00e9e d’une enveloppe fibreuse.<\/p>\n
\nEn l’occurrence, elle correspond \u00e0 un ovocyte I en prophase de premi\u00e8re division de m\u00e9iose<\/a>. Elle est en phase de vitellogen\u00e8se, c’est-\u00e0-dire de d\u00e9p\u00f4t de r\u00e9serves. <\/p>\n
\nCe sont vraisemblablement des ovocytes I ayant atteint le m\u00eame stade de la m\u00e9iose mais dont la vitellogen\u00e8se n’est que peu avanc\u00e9e.<\/p>\n
\nIl s’agit de trophocytes, ou cellules nourrici\u00e8res, d\u00e9rivant d’ovogonies. Connect\u00e9es par des ponts cytoplasmiques \u00e0 l’ovocyte qu’elles accompagnent, elles pourraient jouer un r\u00f4le nutritif et seraient impliqu\u00e9es dans le d\u00e9p\u00f4t du vitellus.<\/p>\n
\nDOI : 10.4322\/jms.117817<\/a><\/p>\n
\nDOI : 10.1016\/S0040-8166(03)00038-7<\/a><\/p>\n
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