![\"Quel](\"\/documents\/images\/histologie_articles\/testicule\/spermatogenese_stade_IIIa_03_vertebres_12-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 r\u00e9sulte de l’observation d’une coupe histologique \u00e0 l’objectif x100 du microscope photonique.<\/p>\n Elle repr\u00e9sente une portion de structure circulaire poss\u00e9dant une lumi\u00e8re centrale, sugg\u00e9rant qu’il s’agit d’une coupe transversale r\u00e9alis\u00e9e dans une unit\u00e9 tubuleuse.<\/p>\n La paroi de la structure tubuleuse est form\u00e9e de plusieurs couches de cellules, de dimensions et de formes diverses, dont les noyaux pr\u00e9sentent des aspects vari\u00e9s. Elle est entour\u00e9e d’une enveloppe fine et fibreuse.<\/p>\n <\/p>\n De la p\u00e9riph\u00e9rie du tube vers la lumi\u00e8re sont distingu\u00e9es des cellules : <\/p>\n • <\/span>de petite taille, plates, dont l’essentiel du volume est repr\u00e9sent\u00e9 par un noyau contenant de fines ponctuations ;<\/p>\n • <\/span>de diam\u00e8tre l\u00e9g\u00e8rement plus important que celui des pr\u00e9c\u00e9dentes, circulaires, \u00e0 noyau volumineux et contenant des filaments bien individualis\u00e9s, reli\u00e9s \u00e0 la face interne de l’enveloppe nucl\u00e9aire par leurs extr\u00e9mit\u00e9s ;<\/p>\n • <\/span>de grande taille, \u00e0 vaste noyau contenant d’\u00e9pais filaments group\u00e9s par deux voire quatre ;<\/p>\n • <\/span>allong\u00e9es, comportant un noyau homog\u00e8ne, en forme de virgule, localis\u00e9 dans la r\u00e9gion des cellules orient\u00e9e vers la p\u00e9riph\u00e9rie du tube.<\/p>\n Au contact de la tunique fibreuse, des cellules pyramidales \u00e0 noyau triangulaire, relativement homog\u00e8ne mais comprenant une tache nette, sont pr\u00e9sentes.<\/p>\n <\/p>\n Les cellules ainsi d\u00e9crites correspondent respectivement \u00e0 des :<\/p>\n • <\/span>spermatogonies<\/a>, cellules dont la multiplication conforme produit de nouvelles spermatogonies ainsi que des spermatocytes I s’engageant dans la formation de spermatozo\u00efdes ;<\/p>\n • <\/span>spermatocytes<\/a> I, entr\u00e9s en prophase de premi\u00e8re division de m\u00e9iose<\/a> et poss\u00e9dant des chromosomes constitu\u00e9s de deux chromatides, appari\u00e9s par paires de chromosomes homologues dont les extr\u00e9mit\u00e9s sont accol\u00e9es \u00e0 la face interne de l’enveloppe nucl\u00e9aire, ils ont atteint le stade zygot\u00e8ne de la prophase ;<\/p>\n • <\/span>spermatocytes I dont les noyaux contiennent des chromosomes form\u00e9s de deux chromatides, associ\u00e9s par paires de chromosomes homologues, les chromatides devenant visibles, ils constituent des t\u00e9trades caract\u00e9ristiques du stade diplot\u00e8ne de la prophase de la premi\u00e8re division de m\u00e9iose ;<\/p>\n • <\/span>spermatides<\/a> tr\u00e8s allong\u00e9es, ayant termin\u00e9 la m\u00e9iose et d\u00e9but\u00e9 leur diff\u00e9renciation en spermatozo\u00efdes<\/a>, appel\u00e9e spermiogen\u00e8se, consistant en une \u00e9limination progressive du cytoplasme, un allongement du noyau et l’acquisition d’un flagelle.<\/p>\n Les cellules pyramidales p\u00e9riph\u00e9riques sont des cellules de Sertoli. Elles assurent une fonction nourrici\u00e8re vis-\u00e0-vis des cellules germinales. <\/p>\n <\/p>\n L’image illustre le processus de spermatogen\u00e8se<\/a> se d\u00e9roulant dans les tubes s\u00e9minif\u00e8res du testicule. L’animal concern\u00e9 est ici un Mammif\u00e8re, la Souris.<\/p>\n Des cellules \u00e0 divers stades de ce processus sont observ\u00e9es dans la m\u00eame section de tube s\u00e9minif\u00e8re. Sa description vient compl\u00e9ter celles des stades I et II, propos\u00e9es respectivement en semaines 09-2017<\/a> et 10-2017<\/a>.<\/p>\n <\/p>\n Une citation \u00ab\u00a0Il est plus ais\u00e9 d’\u00eatre sage pour les autres, que de l’\u00eatre pour soi-m\u00eame.\u00a0\u00bb F. de La Rochefoucauld Une image Voir l’image de plus grande taille Voir l’image l\u00e9gend\u00e9e L’image de la semaine r\u00e9sulte de l’observation d’une coupe histologique \u00e0 l’objectif x100 du microscope photonique. Elle repr\u00e9sente une portion […]<\/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":[14,29,23,25],"class_list":["post-9599","post","type-post","status-publish","format-standard","hentry","category-a-la-une","tag-histologie","tag-mammifere","tag-observation","tag-reproduction"],"aioseo_notices":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/posts\/9599","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=9599"}],"version-history":[{"count":22,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/posts\/9599\/revisions"}],"predecessor-version":[{"id":9753,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/posts\/9599\/revisions\/9753"}],"wp:attachment":[{"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/media?parent=9599"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/categories?post=9599"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/tags?post=9599"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\nIl s’agit de cellules germinales ayant d\u00e9but\u00e9 leurs \u00e9volutions avec un d\u00e9calage temporel, en l’occurrence de spermatogonies, de spermatocytes I aux stade zygot\u00e8ne et diplot\u00e8ne de la prophase de la premi\u00e8re division de m\u00e9iose et de spermatides.
\nLes cellules les moins avanc\u00e9es sont localis\u00e9es en p\u00e9riph\u00e9rie du tube, alors que les cellules les plus avanc\u00e9es occupent la lumi\u00e8re.
\nLeur association d\u00e9finit un stade de l’\u00e9pith\u00e9lium s\u00e9minal, en l’occurrence le stade III.<\/p>\n
\n","protected":false},"excerpt":{"rendered":"