{"id":10646,"date":"2018-01-15T08:00:03","date_gmt":"2018-01-15T07:00:03","guid":{"rendered":"https:\/\/codexvirtualis.fr\/codex\/?p=10646"},"modified":"2018-01-07T15:30:19","modified_gmt":"2018-01-07T14:30:19","slug":"semaine-03-2018","status":"publish","type":"post","link":"https:\/\/codexvirtualis.fr\/codex\/semaine-03-2018","title":{"rendered":"Semaine 03-2018"},"content":{"rendered":"

Une citation<\/h2>\n

\u00ab\u00a0Qu’est-ce que le bonheur sinon le simple accord entre un \u00eatre et l’existence qu’il m\u00e8ne\u00a0?\u00a0\u00bb<\/p>\n

A. Camus<\/p>\n

  <\/p>\n

Une image<\/h2>\n
\"Quel<\/a>
Quel est cet organe ?<\/figcaption><\/figure>\n

  <\/p>\n

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 03-2018 r\u00e9sulte de l’observation d’une coupe histologique \u00e0 l’objectif x100 du microscope photonique.<\/p>\n

  <\/p>\n

Elle est constitu\u00e9e d’une portion de structure d\u00e9limit\u00e9e par une bordure fonc\u00e9e relativement \u00e9paisse.<\/p>\n

Le fond homog\u00e8ne est associ\u00e9 \u00e0 de multiples unit\u00e9s de formes vari\u00e9es. Certaines sont circulaires, intens\u00e9ment color\u00e9es, de dimensions variant entre 4,4 et 1,8\u00b5m. D’autres sont filamenteuses et repli\u00e9es en boucles sym\u00e9triques.<\/p>\n

  <\/p>\n

Cette organisation est caract\u00e9ristique du noyau d’un ovocyte I en phase d’accroissement. La bordure correspond \u00e0 l’enveloppe nucl\u00e9aire, le fond au nucl\u00e9oplasme, les unit\u00e9s circulaires \u00e0 des nucl\u00e9oles et les filaments repli\u00e9s \u00e0 des chromosomes.
\nIl s’agit en l’occurrence d’un ovocyte I d’ovaire de Triton femelle, en prophase de premi\u00e8re division de m\u00e9iose<\/a>. La structure g\u00e9n\u00e9rale de cette cellule est d\u00e9crite dans l’article de la semaine 02-2018<\/a> de Codex virtualis.<\/p>\n

\u00c0 ce stade, les chromosomes homologues sont appari\u00e9s par paires, et chaque chromosome est form\u00e9 de deux chromatides accol\u00e9es. Elles sont localement d\u00e9ploy\u00e9es en boucles sym\u00e9triques, s\u00e9par\u00e9es par des r\u00e9gions rectilignes et contigu\u00ebs appel\u00e9es chromom\u00e8res.
\nL’ensemble d\u00e9termine des figures dites \u00ab\u00a0chromosomes en \u00e9couvillon\u00a0\u00bb, dans lesquelles les r\u00e9gions d\u00e9ploy\u00e9es sont le si\u00e8ge d’une transcription de l’ADN en ARN messagers. Elles r\u00e9v\u00e8lent la production de mol\u00e9cules informatives, stock\u00e9es dans l’ovocytes et traduites apr\u00e8s la f\u00e9condation, au d\u00e9but du d\u00e9veloppement embryonnaire<\/a>.
\nLes chromosomes en \u00e9couvillon sont observ\u00e9s dans les ovocytes de la plupart des animaux au stade diplot\u00e8ne de la prophase de premi\u00e8re division m\u00e9iotique, mais ils sont particuli\u00e8rement visibles chez les Lissamphibiens urod\u00e8les comme le Triton. <\/p>\n

Le cytoplasme situ\u00e9 autour du noyau est envahi de plaquettes vitellines, r\u00e9serves m\u00e9taboliques accumul\u00e9es pendant l’accroissement.<\/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>Heusser S., Dupuy H.G., 2015 \u2013 Atlas biologie animale. Dunod, 220p. Paris<\/p>\n

  <\/p>\n

\n","protected":false},"excerpt":{"rendered":"

Une citation \u00ab\u00a0Qu’est-ce que le bonheur sinon le simple accord entre un \u00eatre et l’existence qu’il m\u00e8ne\u00a0?\u00a0\u00bb A. Camus   Une image   Voir l’image de plus grande taille   Voir l’image l\u00e9gend\u00e9e   L’image de la semaine 03-2018 r\u00e9sulte de l’observation d’une coupe histologique \u00e0 l’objectif x100 du microscope photonique.   Elle est constitu\u00e9e […]<\/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":[10,14,23,22],"class_list":["post-10646","post","type-post","status-publish","format-standard","hentry","category-a-la-une","tag-amphibien","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\/10646","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=10646"}],"version-history":[{"count":9,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/posts\/10646\/revisions"}],"predecessor-version":[{"id":10666,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/posts\/10646\/revisions\/10666"}],"wp:attachment":[{"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/media?parent=10646"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/categories?post=10646"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/tags?post=10646"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}