Exocrine gland

<h2 id="classification">Classification</h2>
<h3>Structure</h3>
<p>Exocrine glands contain a glandular portion and a duct portion, the structures of which can be used to classify the gland.<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a>
</p>
<ul><li>The duct portion may be branched (called compound) or unbranched (called simple).</li>
<li>The glandular portion may be <a href="/facts/Tubular_gland/R6fqQvtw">tubular</a> or <a href="/facts/Acinar_gland/NpVdM17x">acinar</a>, or may be a mix of the two (called tubuloacinar). If the glandular portion branches, then the gland is called a branched gland.</li></ul>
<h3>Method of secretion</h3>
<p>Depending on how their products are secreted, exocrine glands are categorized as <a href="/facts/Merocrine/ICDxEelc">merocrine</a>, <a href="/facts/Apocrine/G7BJvS7I">apocrine</a>, or <a href="/facts/Holocrine/UHsRxPEj">holocrine</a>.<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a>
</p>
<ul><li><a href="/facts/Merocrine/ICDxEelc">Merocrine</a> – the cells of the gland excrete their substances by <a href="/facts/Exocytosis/4P4oQdtA">exocytosis</a> into a duct; for example, pancreatic acinar cells, <a href="/facts/Eccrine_sweat_gland/QrJPP1J5">eccrine sweat glands</a>[<i>dubious – discuss</i>], <a href="/facts/Salivary_gland/VtteDtH0">salivary glands</a>, <a href="/facts/Goblet_cell/FzXnFFr1">goblet cells</a>, <a href="/facts/Intestinal_gland/zoAmee3f">intestinal glands</a>, <a href="/facts/Lacrimal_gland/UlUVYqtB">tear glands</a>, etc.</li>
<li><a href="/facts/Apocrine/G7BJvS7I">Apocrine</a> – the apical portion of the <a href="/facts/Cytoplasm/Wa0sE6xf">cytoplasm</a> in the <a href="/facts/Cell_membrane/vAXSD0DT">cell membrane</a>, which contains the excretion, <a href="/facts/Budding/TEB3zXxB">buds off</a>. Examples are sweat glands of arm pits, pubic region, skin around anus, lips and nipples; <a href="/facts/Mammary_gland/6fVBnNSA">mammary glands</a>, etc.</li>
<li><a href="/facts/Holocrine/UHsRxPEj">Holocrine</a> – the entire cell disintegrates to excrete its substance; for example, sebaceous glands of the <a href="/facts/Skin/4havlLzG">skin</a> and nose, <a href="/facts/Meibomian_gland/9mL1C49F">meibomian gland</a>, <a href="/facts/Gland_of_Zeis/ly6I5Ad4">zeis gland</a>, etc.</li></ul>

<h3>Product secreted</h3>
<ul><li><a href="/facts/Serous_gland/7mdANfX6">Serous cells</a> secrete <a href="/facts/Protein/Jxmagu3E">proteins</a>, often <a href="/facts/Enzyme/DSI1Fh7y">enzymes</a>. Examples include <a href="/facts/Gastric_chief_cell/Yb3L1QsX">gastric chief cells</a> and <a href="/facts/Paneth_cell/GsT8zpXf">Paneth cells</a></li>
<li><a href="/facts/Mucous_gland/aK6zNgDc">Mucous cells</a> secrete <a href="/facts/Mucus/hnlBuHAy">mucus</a>. Examples include <a href="/facts/Brunner%27s_gland/XrF34qNb">Brunner's glands</a>, <a href="/facts/Esophageal_gland/z4v9lR2X">esophageal glands</a>, and <a href="/facts/Pyloric_gland/SQv79wXT">pyloric glands</a></li>
<li>Seromucous glands (mixed) secrete both protein and mucus. Examples include the <a href="/facts/Salivary_gland/VtteDtH0">salivary glands</a>: although the <a href="/facts/Parotid_gland/H4tPjP4D">parotid gland</a> (saliva secretion 25%) is predominantly serous, the <a href="/facts/Sublingual_gland/mjQ9fSo9">sublingual gland</a> (saliva secretion 5%) mainly mucous gland, and the <a href="/facts/Submandibular_gland/qBKM1P31">submandibular gland</a> (saliva secretion 70%) is a mixed, mainly serous gland.</li>
<li><a href="/facts/Sebaceous_gland/HKMXmv1Y">Sebaceous glands</a> secrete <a href="/facts/Sebaceous_gland/HKMXmv1Y">sebum</a>, a lipid product. These glands are also known as oil glands, e.g. <a href="/facts/Fordyce_spots/PnUJCw00">Fordyce spots</a> and <a href="/facts/Meibomian_glands/9mL1C49F">Meibomian glands</a>.</li></ul>
<h2 id="additional-images">Additional images</h2>

<h2 id="see-also">See also</h2>
<ul>
<li>Anatomy portal</li></ul>
<ul><li><a href="/facts/List_of_glands_of_the_human_body/JHEdY9ad">List of glands of the human body</a></li>
<li><a href="/facts/List_of_specialized_glands_within_the_human_integumentary_system/JHEdY9ad">List of specialized glands within the human integumentary system</a></li></ul>

<h2 id="external-links">External links</h2>
<ul><li><a href="https://web.archive.org/web/20170426040555/http://www.mhhe.com/biosci/ap/histology_mh/glands.html">Diagram at mhhe.com</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>Young, Barbara; O'Dowd, Geraldine; Woodford, Phillip (2013). Wheater's Functional Histology: A Text and Colour Atlas (Sixth ed.). Elsevier. p. 95. ISBN 978-0702047473. LCCN 2013036824. <a href="978-0702047473" target="_blank">978-0702047473</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>Young, Barbara; O'Dowd, Geraldine; Woodford, Phillip (2013). Wheater's Functional Histology: A Text and Colour Atlas (Sixth ed.). Elsevier. p. 95. ISBN 978-0702047473. LCCN 2013036824. <a href="978-0702047473" target="_blank">978-0702047473</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>Young, Barbara; O'Dowd, Geraldine; Woodford, Phillip (2013). Wheater's Functional Histology: A Text and Colour Atlas (Sixth ed.). Elsevier. p. 95. ISBN 978-0702047473. LCCN 2013036824. <a href="978-0702047473" target="_blank">978-0702047473</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
</ol>

Exocrine gland open-in-new

Exocrine gland