{"id":689,"date":"2017-05-22T15:11:38","date_gmt":"2017-05-22T18:11:38","guid":{"rendered":"http:\/\/en-mol.icb.usp.br\/?page_id=689"},"modified":"2026-08-24T16:58:57","modified_gmt":"2026-08-24T19:58:57","slug":"2-5-covering-epithelia","status":"publish","type":"page","link":"https:\/\/mol-en.icb.usp.br\/index.php\/2-5-covering-epithelia\/","title":{"rendered":"2-5 Covering epithelia"},"content":{"rendered":"<div class=\"su-row\">\n  <div class=\"su-column su-column-size-1-1\"><div class=\"su-column-inner su-u-clearfix su-u-trim\"> <strong>WHICH TISSUE IS THIS?  &#8211; 3<\/strong> <\/div><\/div>\n<\/div>\n<div class=\"su-row\">\n  <div class=\"su-column su-column-size-1-2\"><div class=\"su-column-inner su-u-clearfix su-u-trim\">\nStill unsure how to distinguish the epithelium from the connective tissue? Pay close attention to the following details:<\/p>\n<p>In the epithelium, the cell nuclei are clearly visible. The acidophilic (pink) areas surrounding each nucleus correspond to the cytoplasm of the epithelial cells. There is very little space between neighboring cells because they are closely packed together.<br \/>\nIn the connective tissue, the nuclei are more widely separated from one another. The cytoplasm surrounding each nucleus is often thin and may be difficult to see. Much of the space between the cells is occupied by extracellular matrix, which contains numerous pink collagen fibers of different sizes and thicknesses. Some apparently empty spaces are also present. These spaces are most likely technical artifacts produced during tissue preparation, when components of the extracellular matrix shrink or retract.<br \/>\nBlood vessels: There are no blood vessels within the epithelium, whereas blood vessels can be found in the underlying connective tissue. The vessels supply the epithelium indirectly by allowing oxygen and nutrients to diffuse from the connective tissue to the epithelial cells.<\/p>\n<p><img decoding=\"async\" src=\" https:\/\/mol-en.icb.usp.br\/wp-content\/uploads\/2-8B.jpg\" \/><\/a><\/p>\n<p>The connective tissue layer that lies beneath the epithelia lining the internal cavities of the digestive, respiratory, and urinary systems is called <strong>lamina propria<\/strong>.<br \/>\nThe combination of an epithelium and its underlying lamina propria that covers the <strong>moist surfaces<\/strong> of internal body cavities is called  <strong>mucous membrane<\/strong>, commonly shortened to <strong>mucosa<\/strong>. Examples include the oral mucosa and gastric mucosa.<\/p>\n<p>The epithelial layer that covers the <strong>outer surfaces<\/strong> of organs located within the major body cavities, such as the thoracic and abdominal cavities, is called <strong>mesothelium<\/strong>.<\/p>\n<p>The epithelium that lines the <strong>inner surface of blood vessels<\/strong> is called <strong>endothelium<\/strong>.<br \/>\nCheck the <strong><https:\/\/mol-en.icb.usp.br\/index.php\/Glossary\/\" rel=\"noopener\" target=\"_blank\">Glossary<\/a><\/strong> to clarify your doubts about terms mentioned in this and other chapters (access via the Menu at the top of all pages).<\/p>\n<p><a href=https:\/\/mol-en.icb.usp.br\/index.php\/2-6-covering-epithelia\/\">NEXT PAGE<\/a><\/p>\n<p><a href=https:\/\/mol-en.icb.usp.br\/index.php\/2-4-covering-epithelia\/\/\">PREVIOUS PAGE <\/a><\/p>\n<p><a href=https:\/\/mol-en.icb.usp.br\/index.php\/2-0-epithelial-tissue\/\">MENU OF THIS CHAPTER<\/a><\/p>\n<\/div><\/div>\n  <div class=\"su-column su-column-size-1-2\"><div class=\"su-column-inner su-u-clearfix su-u-trim\"> <\/p>\n<\/div><\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":2,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-689","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/mol-en.icb.usp.br\/index.php\/wp-json\/wp\/v2\/pages\/689","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mol-en.icb.usp.br\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/mol-en.icb.usp.br\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/mol-en.icb.usp.br\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/mol-en.icb.usp.br\/index.php\/wp-json\/wp\/v2\/comments?post=689"}],"version-history":[{"count":54,"href":"https:\/\/mol-en.icb.usp.br\/index.php\/wp-json\/wp\/v2\/pages\/689\/revisions"}],"predecessor-version":[{"id":24696,"href":"https:\/\/mol-en.icb.usp.br\/index.php\/wp-json\/wp\/v2\/pages\/689\/revisions\/24696"}],"wp:attachment":[{"href":"https:\/\/mol-en.icb.usp.br\/index.php\/wp-json\/wp\/v2\/media?parent=689"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}