{"id":12012,"date":"2019-05-13T08:00:53","date_gmt":"2019-05-13T06:00:53","guid":{"rendered":"https:\/\/codexvirtualis.fr\/codex\/?p=12012"},"modified":"2019-05-16T21:22:37","modified_gmt":"2019-05-16T19:22:37","slug":"semaine-20-2019","status":"publish","type":"post","link":"https:\/\/codexvirtualis.fr\/codex\/semaine-20-2019","title":{"rendered":"Semaine 20-2019"},"content":{"rendered":"

Une citation<\/h2>\n

\u00ab\u00a0L’homme sans patience est une lampe sans huile.\u00a0\u00bb<\/p>\n

A. de Musset<\/p>\n

  <\/p>\n

Une image<\/h2>\n
\"Quel
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 20-2019 provient de l’observation d’une coupe <\/a>histologique<\/a> \u00e0 l’objectif x20 du microscope photonique.<\/p>\n

Elle comporte une masse centrale baignant dans un espace semblant vide, mais contenant des unit\u00e9s diverses dispers\u00e9es. La masse centrale est elle-m\u00eame creus\u00e9e d’une lacune, bord\u00e9e d’une paroi relativement \u00e9paisse. Il s’agit vraisemblablement d’une structure tubuleuse coup\u00e9e transversalement.<\/p>\n

  <\/p>\n

La paroi d\u00e9limitant la lacune appara\u00eet form\u00e9e d’unit\u00e9s accol\u00e9es les unes aux autres, agenc\u00e9es en une unique couche. Chacune contient une sous-unit\u00e9s ovale intens\u00e9ment color\u00e9e, entour\u00e9e de mati\u00e8re h\u00e9t\u00e9rog\u00e8ne comprenant de fines et de volumineuses granulations.<\/p>\n

Cette organisation est caract\u00e9ristique des cellules<\/a> animales, la sous-unit\u00e9 ovale correspondant au noyau et la mati\u00e8re h\u00e9t\u00e9rog\u00e8ne au cytoplasme<\/a>.
\nL’agencement des cellules en une couche continue d\u00e9termine un \u00e9pith\u00e9lium<\/a> simple.
\nLa hauteur des cellules \u00e9tant relativement \u00e9lev\u00e9e, il est de type cubique. La pr\u00e9sence dans la lumi\u00e8re de longs filaments ondul\u00e9s sugg\u00e8re que ses cellules sont cili\u00e9es<\/a>.<\/p>\n

  <\/p>\n

La masse centrale est envelopp\u00e9e d’une fine couche continue. Elle comporte des renflements correspondant \u00e0 des noyaux plats. Il s’agit d’un \u00e9pith\u00e9lium simple et pavimenteux localis\u00e9 au contact de l’espace semblant vide.<\/p>\n

L’espace vide est vraisemblablement une cavit\u00e9 liquidienne, dans laquelle des cellules libres sont pr\u00e9sentes sous forme d’unit\u00e9s dispers\u00e9es.<\/p>\n

De tels vastes espaces liquidiens contenant des cellules isol\u00e9es vari\u00e9es sont rencontr\u00e9s dans le groupe des Ann\u00e9lides<\/a>, et notamment chez le Lombric \u00e9galement appel\u00e9 Ver de terre. Ce sont des cavit\u00e9s c\u0153lomiques<\/a> remplies de liquide c\u0153lomique contenant de nombreuses cellules, les c\u0153lomocytes.
\nLes cavit\u00e9s c\u0153lomiques sont d\u00e9crites dans les articles des semaines 41-2018<\/a> et 42-2018<\/a> de Codex virtualis, et les c\u0153lomocytes dans les articles des semaines 37-2018<\/a>, 38-2018<\/a> et 39-2018<\/a>.<\/p>\n

Parmi les tubes baignant dans les cavit\u00e9s c\u0153lomiques figurent les tubes n\u00e9phridiens, constituants des organes excr\u00e9teurs<\/a>, les m\u00e9tan\u00e9phridies.
\nChaque m\u00e9tam\u00e8re<\/a> corporel du Lombric est organis\u00e9 autour d’une cavit\u00e9 c\u0153lomique et comporte une paire de m\u00e9tan\u00e9phridies. Chacune est form\u00e9e d’un entonnoir cili\u00e9 appel\u00e9 n\u00e9phrostome, d\u00e9crit dans l’article de la semaine 17-2019<\/a>, et d’un tube n\u00e9phridien.<\/p>\n

  <\/p>\n

Le n\u00e9phrostome est responsable du transfert du liquide c\u0153lomique contenant les d\u00e9chets m\u00e9taboliques dans la m\u00e9tan\u00e9phridie. Il est \u00e0 l’origine de l’urine primitive.<\/p>\n

Le tube n\u00e9phridien assure la modification de la composition de l’urine primitive et la transforme en urine d\u00e9finitive. Il comporte plusieurs segments distincts par leurs dimensions, leurs structures et leurs fonctions.
\nLe segment gr\u00eale, situ\u00e9 imm\u00e9diatement en aval du n\u00e9phrostome et d\u00e9crit dans l’article de la semaine 19-2019<\/a>, est impliqu\u00e9 dans la s\u00e9cr\u00e9tion de d\u00e9chets azot\u00e9s.<\/p>\n

Le segment moyen qui lui fait suite, et est l’objet de l’article de la semaine 20-2019, a une organisation voisine. Il pr\u00e9sente cependant un diam\u00e8tre plus important, de l’ordre de 60\u00b5m, et un \u00e9pith\u00e9lium plus \u00e9pais. Il est le si\u00e8ge de r\u00e9absorptions d’ions et d’eau depuis l’urine vers le sang.<\/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>Goodrich E.S., 1932 \u2013 On the nephridiostome of Lumbricus<\/em>.<\/a> Quarterly journal of microscopical science, 75 : 165-179 (adresse : http:\/\/jcs.biologists.org\/content\/joces\/s2-75\/297\/165.full.pdf)<\/p>\n

• <\/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>Ramsay J.A., 1949 \u2013 The site of formation of hypotonic urine in the nephridium of Lumbricus<\/em><\/a>. Journal of experimental biology, 26 : 65-75 (adresse : http:\/\/jeb.biologists.org\/content\/jexbio\/26\/1\/65.full.pdf)<\/p>\n

  <\/p>\n

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

Une citation \u00ab\u00a0L’homme sans patience est une lampe sans huile.\u00a0\u00bb A. de Musset   Une image   Voir l’image de plus grande taille   Voir l’image l\u00e9gend\u00e9e   L’image de la semaine 20-2019 provient de l’observation d’une coupe histologique \u00e0 l’objectif x20 du microscope photonique. Elle comporte une masse centrale baignant dans un espace semblant […]<\/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-12012","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\/12012","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=12012"}],"version-history":[{"count":14,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/posts\/12012\/revisions"}],"predecessor-version":[{"id":12020,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/posts\/12012\/revisions\/12020"}],"wp:attachment":[{"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/media?parent=12012"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/categories?post=12012"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/tags?post=12012"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}