{"id":4271,"date":"2017-03-28T18:58:00","date_gmt":"2017-03-28T18:58:00","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/wm-biology2\/?post_type=chapter&#038;p=4271"},"modified":"2024-04-26T02:42:06","modified_gmt":"2024-04-26T02:42:06","slug":"protection-and-sensory-function","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/wm-biology2\/chapter\/protection-and-sensory-function\/","title":{"raw":"Protection and Sensory Function","rendered":"Protection and Sensory Function"},"content":{"raw":"<div class=\"textbox learning-objectives\">\r\n<h3>Learning Outcomes<\/h3>\r\n<ul>\r\n \t<li>Describe the role the integumentary system plays in protection and sensation<\/li>\r\n<\/ul>\r\n<\/div>\r\n<h2>Protection<\/h2>\r\nThe skin protects the body against pathogens and chemicals, minimizes loss or entry of water, and blocks the harmful effects of sunlight.\u00a0It also is the first line of defense against abrasive activity due to contact with grit, microbes, or harmful chemicals.\r\n\r\nThe skin flora, or\u00a0microorganisms which reside on the skin, play an important role in protection. The skin flora can protect the human host by preventing transient pathogenic organisms from colonizing the skin surface, either by competing for nutrients, secreting chemicals against them, or stimulating the skin's immune system.\u00a0Sweat excreted from sweat glands also deters microbes from over-colonizing the skin surface by generating dermicidin, which has antibiotic properties.\u00a0Another factor affecting the growth of pathological bacteria is alkaline conditions. Bacteria are unable to attach effectively to the skin and are more readily shed in alkaline conditions.\r\n\r\nSkin acts as a protective barrier against water loss, due to the presence of layers of keratin and glycolipids in the stratum corneum.\u00a0The cells of the stratum corneum can also absorb water, further aiding in hydration.\r\n<h2>Sensory Function<\/h2>\r\n[caption id=\"attachment_2858\" align=\"alignright\" width=\"400\"]<img class=\"wp-image-2858\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/02\/08172240\/514_Light_Micrograph_of_a_Meissner_Corpuscle.jpg\" alt=\"This micrograph shows a skin cross section at low magnification. The Meissner\u2019s corpuscle is a large, oval-shaped structure located in the papillary layer of the dermis, under the lowest deepest layer of the epidermis. The corpuscle contains a dark staining oval within the outer, light staining oval. Several horizontal bars are arranged vertically within the inner oval. Also, several cells with dark purple nuclei can be seen scattered throughout the corpuscle.\" width=\"400\" height=\"300\" \/> Figure 1. In this micrograph of a skin cross-section, you can see a Meissner corpuscle (arrow), a type of touch receptor located in a dermal papilla adjacent to the basement membrane and stratum basale of the overlying epidermis. LM \u00d7 100. (credit: \u201cWbensmith\u201d\/Wikimedia Commons)[\/caption]\r\n\r\nThe fact that you can feel an ant crawling on your skin, allowing you to flick it off before it bites, is because the skin, and especially the hairs projecting from hair follicles in the skin, can sense changes in the environment. The hair root plexus surrounding the base of the hair follicle senses a disturbance, and then transmits the information to the central nervous system (brain and spinal cord), which can then respond by activating the skeletal muscles of your eyes to see the ant and the skeletal muscles of the body to act against the ant.\r\n\r\nThe skin acts as a sense organ because the epidermis, dermis, and the hypodermis contain specialized sensory nerve structures that detect touch, surface temperature, and pain. These receptors are more concentrated on the tips of the fingers, which are most sensitive to touch, especially the <strong>Meissner corpuscle<\/strong> (tactile corpuscle) (Figure 1), which responds to light touch, and the <strong>Pacinian corpuscle<\/strong> (lamellated corpuscle), which responds to vibration. Merkel cells, seen scattered in the stratum basale, are also touch receptors. In addition to these specialized receptors, there are sensory nerves connected to each hair follicle, pain and temperature receptors scattered throughout the skin, and motor nerves innervate the arrector pili muscles and glands. This rich innervation helps us sense our environment and react accordingly.\r\n<div class=\"textbox tryit\">\r\n<h3>Try It<\/h3>\r\nhttps:\/\/assess.lumenlearning.com\/practice\/4f14f13d-84bb-4a3e-935f-3c90332e3fc2\r\n<\/div>","rendered":"<div class=\"textbox learning-objectives\">\n<h3>Learning Outcomes<\/h3>\n<ul>\n<li>Describe the role the integumentary system plays in protection and sensation<\/li>\n<\/ul>\n<\/div>\n<h2>Protection<\/h2>\n<p>The skin protects the body against pathogens and chemicals, minimizes loss or entry of water, and blocks the harmful effects of sunlight.\u00a0It also is the first line of defense against abrasive activity due to contact with grit, microbes, or harmful chemicals.<\/p>\n<p>The skin flora, or\u00a0microorganisms which reside on the skin, play an important role in protection. The skin flora can protect the human host by preventing transient pathogenic organisms from colonizing the skin surface, either by competing for nutrients, secreting chemicals against them, or stimulating the skin&#8217;s immune system.\u00a0Sweat excreted from sweat glands also deters microbes from over-colonizing the skin surface by generating dermicidin, which has antibiotic properties.\u00a0Another factor affecting the growth of pathological bacteria is alkaline conditions. Bacteria are unable to attach effectively to the skin and are more readily shed in alkaline conditions.<\/p>\n<p>Skin acts as a protective barrier against water loss, due to the presence of layers of keratin and glycolipids in the stratum corneum.\u00a0The cells of the stratum corneum can also absorb water, further aiding in hydration.<\/p>\n<h2>Sensory Function<\/h2>\n<div id=\"attachment_2858\" style=\"width: 410px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-2858\" class=\"wp-image-2858\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/02\/08172240\/514_Light_Micrograph_of_a_Meissner_Corpuscle.jpg\" alt=\"This micrograph shows a skin cross section at low magnification. The Meissner\u2019s corpuscle is a large, oval-shaped structure located in the papillary layer of the dermis, under the lowest deepest layer of the epidermis. The corpuscle contains a dark staining oval within the outer, light staining oval. Several horizontal bars are arranged vertically within the inner oval. Also, several cells with dark purple nuclei can be seen scattered throughout the corpuscle.\" width=\"400\" height=\"300\" \/><\/p>\n<p id=\"caption-attachment-2858\" class=\"wp-caption-text\">Figure 1. In this micrograph of a skin cross-section, you can see a Meissner corpuscle (arrow), a type of touch receptor located in a dermal papilla adjacent to the basement membrane and stratum basale of the overlying epidermis. LM \u00d7 100. (credit: \u201cWbensmith\u201d\/Wikimedia Commons)<\/p>\n<\/div>\n<p>The fact that you can feel an ant crawling on your skin, allowing you to flick it off before it bites, is because the skin, and especially the hairs projecting from hair follicles in the skin, can sense changes in the environment. The hair root plexus surrounding the base of the hair follicle senses a disturbance, and then transmits the information to the central nervous system (brain and spinal cord), which can then respond by activating the skeletal muscles of your eyes to see the ant and the skeletal muscles of the body to act against the ant.<\/p>\n<p>The skin acts as a sense organ because the epidermis, dermis, and the hypodermis contain specialized sensory nerve structures that detect touch, surface temperature, and pain. These receptors are more concentrated on the tips of the fingers, which are most sensitive to touch, especially the <strong>Meissner corpuscle<\/strong> (tactile corpuscle) (Figure 1), which responds to light touch, and the <strong>Pacinian corpuscle<\/strong> (lamellated corpuscle), which responds to vibration. Merkel cells, seen scattered in the stratum basale, are also touch receptors. In addition to these specialized receptors, there are sensory nerves connected to each hair follicle, pain and temperature receptors scattered throughout the skin, and motor nerves innervate the arrector pili muscles and glands. This rich innervation helps us sense our environment and react accordingly.<\/p>\n<div class=\"textbox tryit\">\n<h3>Try It<\/h3>\n<p>\t<iframe id=\"assessment_practice_4f14f13d-84bb-4a3e-935f-3c90332e3fc2\" class=\"resizable\" src=\"https:\/\/assess.lumenlearning.com\/practice\/4f14f13d-84bb-4a3e-935f-3c90332e3fc2?iframe_resize_id=assessment_practice_id_4f14f13d-84bb-4a3e-935f-3c90332e3fc2\" frameborder=\"0\" style=\"border:none;width:100%;height:100%;min-height:300px;\"><br \/>\n\t<\/iframe>\n<\/div>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-4271\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>Anatomy &amp; Physiology. <strong>Provided by<\/strong>: OpenStax. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/cnx.org\/contents\/14fb4ad7-39a1-4eee-ab6e-3ef2482e3e22@8.79\">http:\/\/cnx.org\/contents\/14fb4ad7-39a1-4eee-ab6e-3ef2482e3e22@8.79<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em>. <strong>License Terms<\/strong>: Download for free at http:\/\/cnx.org\/contents\/14fb4ad7-39a1-4eee-ab6e-3ef2482e3e22@8.79<\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section>","protected":false},"author":17,"menu_order":12,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Anatomy & Physiology\",\"author\":\"\",\"organization\":\"OpenStax\",\"url\":\"http:\/\/cnx.org\/contents\/14fb4ad7-39a1-4eee-ab6e-3ef2482e3e22@8.79\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"Download for free at http:\/\/cnx.org\/contents\/14fb4ad7-39a1-4eee-ab6e-3ef2482e3e22@8.79\"}]","CANDELA_OUTCOMES_GUID":"250edd0b-345a-4a27-9a88-294b1947460b, 30e46a42-c1f6-445f-8f58-78aca8872b91","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-4271","chapter","type-chapter","status-publish","hentry"],"part":3797,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/4271","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/users\/17"}],"version-history":[{"count":11,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/4271\/revisions"}],"predecessor-version":[{"id":8715,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/4271\/revisions\/8715"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/parts\/3797"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/4271\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/media?parent=4271"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapter-type?post=4271"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/contributor?post=4271"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/license?post=4271"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}