{"id":858,"date":"2019-07-22T19:53:35","date_gmt":"2019-07-22T23:53:35","guid":{"rendered":"https:\/\/pressbooks.bccampus.ca\/pathology\/chapter\/cardiac-muscle-tissue\/"},"modified":"2025-11-05T23:17:36","modified_gmt":"2025-11-06T04:17:36","slug":"cardiac-muscle-tissue","status":"publish","type":"chapter","link":"https:\/\/pressbooks.bccampus.ca\/pathology\/chapter\/cardiac-muscle-tissue\/","title":{"raw":"Cardiac Muscle Tissue","rendered":"Cardiac Muscle Tissue"},"content":{"raw":"<div class=\"textbox textbox--learning-objectives\">\r\n<div class=\"textbox textbox--learning-objectives\"><header class=\"textbox__header\">\r\n<p class=\"textbox__title\">Learning Objectives<\/p>\r\n\r\n<\/header>\r\n<div class=\"textbox__content\">\r\n\r\nBy the end of this section, you will be able to:\r\n<ul>\r\n \t<li>Describe intercalated discs and gap junctions.<\/li>\r\n \t<li>Describe a desmosome.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\nCardiac muscle tissue is only found in the heart. Highly coordinated contractions of cardiac muscle pump blood into the vessels of the circulatory system. Similar to skeletal muscle, cardiac muscle is striated and organized into sarcomeres, possessing the same banding organization as <a href=\"#fig-ch10_07_01\">skeletal muscle.<\/a>\u00a0However, cardiac muscle fibers are shorter than skeletal muscle fibers and usually contain only one nucleus, which is located in the central region of the cell. Cardiac muscle fibers also possess many mitochondria and myoglobin, as ATP is produced primarily through aerobic metabolism. Cardiac muscle fibers cells also are extensively branched and are connected to one another at their ends by [pb_glossary id=\"2152\"]intercalated discs[\/pb_glossary]. An intercalated disc allows the cardiac muscle cells to contract in a wave-like pattern so that the heart can work as a pump.\r\n<div id=\"fig-ch10_07_01\" class=\"bc-figure figure\">\r\n<div data-type=\"title\"><\/div>\r\n\r\n[caption id=\"attachment_856\" align=\"aligncenter\" width=\"591\"]<img class=\"size-full wp-image-856\" src=\"https:\/\/pressbooks.bccampus.ca\/pathology\/wp-content\/uploads\/sites\/1260\/2021\/08\/414c_Cardiacmuscle-1.jpg\" alt=\"This image is a micrograph of cardiac muscle cells. cardiomyocytes are long red rectangles laid in parallel. A large purple nucleus is large enough to take up the entire width of the rectangular cells. The cells are offset such that the nuclei are laid out in parallel but random patterns.\" width=\"591\" height=\"403\" \/> Cardiac Muscle Tissue LM \u00d7 1600. (Micrograph provided by the Regents of University of Michigan Medical School \u00a9 2012)[\/caption]\r\n\r\n<div class=\"bc-figcaption figcaption\"><\/div>\r\n<\/div>\r\n<div id=\"fs-id2327137\" class=\"anatomy interactive um\" data-type=\"note\" data-has-label=\"true\" data-label=\"\">\r\n<div class=\"bc-figcaption figcaption\"><\/div>\r\nView the <a href=\"http:\/\/openstax.org\/l\/cardmuscleMG\">University of Michigan WebScope<\/a> to explore the tissue sample in greater detail.\r\n\r\n<\/div>\r\nIntercalated discs are part of the sarcolemma and contain two structures important in cardiac muscle contraction: gap junctions and [pb_glossary id=\"2151\"]desmosomes[\/pb_glossary]. A gap junction forms channels between adjacent cardiac muscle fibers that allow the depolarizing current produced by cations to flow from one cardiac muscle cell to the next. This joining is called electric coupling, and in cardiac muscle it allows the quick transmission of action potentials and the coordinated contraction of the entire heart. This network of electrically connected cardiac muscle cells creates a functional unit of contraction called a syncytium. The remainder of the intercalated disc is composed of desmosomes. A desmosome is a cell structure that anchors the ends of cardiac muscle fibers together so the cells do not pull apart during the stress of <a href=\"#fig-ch10_07_02\">individual fibers contracting<\/a>.\r\n<div id=\"fig-ch10_07_02\" class=\"bc-figure figure\">\r\n<div data-type=\"title\"><\/div>\r\n\r\n[caption id=\"attachment_857\" align=\"aligncenter\" width=\"1018\"]<img class=\"size-full wp-image-857\" src=\"https:\/\/pressbooks.bccampus.ca\/pathology\/wp-content\/uploads\/sites\/1260\/2021\/08\/1020_Cardiac_Muscle-1.jpg\" alt=\"This image shows the structure of the cardiac muscle. A small image of the heart is shown on the top left of the figure and then a magnified view of the cardiac muscle is shown, with the nucleus and the cardiac muscle fiber labeled. A further magnification shows the structure of the intercalated discs with the desmosome and gap junction.\" width=\"1018\" height=\"476\" \/> Intercalated discs are part of the cardiac muscle sarcolemma and they contain gap junctions and desmosomes.[\/caption]\r\n\r\n<div class=\"bc-figcaption figcaption\"><\/div>\r\n<\/div>\r\nContractions of the heart (heartbeats) are controlled by specialized cardiac muscle cells called pacemaker cells that directly control heart rate. Although cardiac muscle cannot be consciously controlled, the pacemaker cells respond to signals from the autonomic nervous system (ANS) to speed up or slow down the heart rate. The pacemaker cells can also respond to various hormones that modulate heart rate to control blood pressure.\r\n\r\nThe wave of contraction that allows the heart to work as a unit, called a functional syncytium, begins with the pacemaker cells. This group of cells is self-excitable and able to depolarize to threshold and fire action potentials on their own, a feature called [pb_glossary id=\"2150\"]autorhythmicity[\/pb_glossary]; they do this at set intervals which determine heart rate. Because they are connected with gap junctions to surrounding muscle fibers and the specialized fibers of the heart\u2019s conduction system, the pacemaker cells are able to transfer the depolarization to the other cardiac muscle fibers in a manner that allows the heart to contract in a coordinated manner.\r\n\r\nAnother feature of cardiac muscle is its relatively long action potentials in its fibers, having a sustained depolarization \u201cplateau.\u201d The plateau is produced by Ca<sup>++<\/sup> entry though voltage-gated calcium channels in the sarcolemma of cardiac muscle fibers. This sustained depolarization (and Ca<sup>++<\/sup> entry) provides for a longer contraction than is produced by an action potential in skeletal muscle. Unlike skeletal muscle, a large percentage of the Ca<sup>++<\/sup> that initiates contraction in cardiac muscles comes from outside the cell rather than from the SR.\r\n<div class=\"textbox textbox--exercises\"><header class=\"textbox__header\">\r\n<p class=\"textbox__title\">Critical Thinking Exercise<\/p>\r\n\r\n<\/header>\r\n<div class=\"textbox__content\">\r\n\r\nAnswer these questions for yourself:\r\n<ul>\r\n \t<li>Consider the function of cardiac muscle cells\r\n<ul>\r\n \t<li>How do the shape, structure, arrangement, size, and number of these cells support their function?<\/li>\r\n \t<li>Speculate on the level of cellular change that can affect these cells and their function.<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n<h2>Section Review<\/h2>\r\nCardiac muscle is striated muscle that is found exclusively in the heart. Cardiac muscle fibers are branched, contain a single nucleus, and are joined to one another by intercalated discs. These discs contain gap junctions for depolarization between cells and desmosomes to hold the fibers together when the heart contracts. Contraction in each cardiac muscle fiber is triggered by Ca<sup>++<\/sup> ions in a similar manner as skeletal muscle, but here the Ca<sup>++<\/sup> ions come from sarcoplasmic reticulum (SR) and through voltage-gated calcium channels in the sarcolemma. Pacemaker cells stimulate the spontaneous contraction of cardiac muscle as a functional unit, called a syncytium.\r\n<h1>Review Questions<\/h1>\r\n<div class=\"h5p\">[h5p id=\"19\"]<\/div>\r\n<div class=\"pdf\">\r\n\r\n<strong>1. Finish the following sentence. Cardiac muscles differ from skeletal muscles in that they:<\/strong>\r\n<ul>\r\n \t<li>Are striated<\/li>\r\n \t<li>Utilize aerobic metabolism<\/li>\r\n \t<li>Contain myofibrils<\/li>\r\n \t<li>Contain intercalated discs<\/li>\r\n<\/ul>\r\n<strong>2. Finish the following sentence. If cardiac muscle cells were prevented from undergoing aerobic metabolism, they ultimately would:<\/strong>\r\n<ul>\r\n \t<li>Undergo glycolysis<\/li>\r\n \t<li>Synthesize ATP<\/li>\r\n \t<li>Stop contracting<\/li>\r\n \t<li>Start contracting<\/li>\r\n<\/ul>\r\n<strong>3. What would be the drawback of cardiac contractions being the same duration as skeletal muscle contractions?<\/strong>\r\n\r\n<strong>4. How are cardiac muscle cells similar to and different from skeletal muscle cells?<\/strong>\r\n<div class=\"textbox\">\r\n<h2>Answer Key<\/h2>\r\n<ol>\r\n \t<li>Contain intercalated discs<\/li>\r\n \t<li>Stop contracting<\/li>\r\n \t<li>An action potential could reach a cardiac muscle cell before it has entered the relaxation phase, resulting in the sustained contractions of tetanus. If this happened, the heart would not beat regularly.<\/li>\r\n \t<li>Cardiac and skeletal muscle cells both contain ordered myofibrils and are striated. Cardiac muscle cells are branched and contain intercalated discs, which skeletal muscles do not have.<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n&nbsp;\r\n<h1>Adaption<\/h1>\r\nThis chapter is adapted from the following text:\r\n\r\n<a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/19-2-cardiac-muscle-and-electrical-activity\" target=\"_blank\" rel=\"noopener\">Cardiac muscle and electrical activity<\/a>\u00a0<strong>in\u00a0<\/strong><a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\">Anatomy and Physiology<\/a>\u00a0by\u00a0OSCRiceUniversity\u00a0is licensed under a\u00a0<a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">Creative Commons Attribution 4.0 International License<\/a>","rendered":"<div class=\"textbox textbox--learning-objectives\">\n<div class=\"textbox textbox--learning-objectives\">\n<header class=\"textbox__header\">\n<p class=\"textbox__title\">Learning Objectives<\/p>\n<\/header>\n<div class=\"textbox__content\">\n<p>By the end of this section, you will be able to:<\/p>\n<ul>\n<li>Describe intercalated discs and gap junctions.<\/li>\n<li>Describe a desmosome.<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<\/div>\n<p>Cardiac muscle tissue is only found in the heart. Highly coordinated contractions of cardiac muscle pump blood into the vessels of the circulatory system. Similar to skeletal muscle, cardiac muscle is striated and organized into sarcomeres, possessing the same banding organization as <a href=\"#fig-ch10_07_01\">skeletal muscle.<\/a>\u00a0However, cardiac muscle fibers are shorter than skeletal muscle fibers and usually contain only one nucleus, which is located in the central region of the cell. Cardiac muscle fibers also possess many mitochondria and myoglobin, as ATP is produced primarily through aerobic metabolism. Cardiac muscle fibers cells also are extensively branched and are connected to one another at their ends by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_858_2152\">intercalated discs<\/a>. An intercalated disc allows the cardiac muscle cells to contract in a wave-like pattern so that the heart can work as a pump.<\/p>\n<div id=\"fig-ch10_07_01\" class=\"bc-figure figure\">\n<div data-type=\"title\"><\/div>\n<figure id=\"attachment_856\" aria-describedby=\"caption-attachment-856\" style=\"width: 591px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-856\" src=\"https:\/\/pressbooks.bccampus.ca\/pathology\/wp-content\/uploads\/sites\/1260\/2021\/08\/414c_Cardiacmuscle-1.jpg\" alt=\"This image is a micrograph of cardiac muscle cells. cardiomyocytes are long red rectangles laid in parallel. A large purple nucleus is large enough to take up the entire width of the rectangular cells. The cells are offset such that the nuclei are laid out in parallel but random patterns.\" width=\"591\" height=\"403\" srcset=\"https:\/\/pressbooks.bccampus.ca\/pathology\/wp-content\/uploads\/sites\/1260\/2021\/08\/414c_Cardiacmuscle-1.jpg 591w, https:\/\/pressbooks.bccampus.ca\/pathology\/wp-content\/uploads\/sites\/1260\/2021\/08\/414c_Cardiacmuscle-1-300x205.jpg 300w, https:\/\/pressbooks.bccampus.ca\/pathology\/wp-content\/uploads\/sites\/1260\/2021\/08\/414c_Cardiacmuscle-1-65x44.jpg 65w, https:\/\/pressbooks.bccampus.ca\/pathology\/wp-content\/uploads\/sites\/1260\/2021\/08\/414c_Cardiacmuscle-1-225x153.jpg 225w, https:\/\/pressbooks.bccampus.ca\/pathology\/wp-content\/uploads\/sites\/1260\/2021\/08\/414c_Cardiacmuscle-1-350x239.jpg 350w\" sizes=\"auto, (max-width: 591px) 100vw, 591px\" \/><figcaption id=\"caption-attachment-856\" class=\"wp-caption-text\">Cardiac Muscle Tissue LM \u00d7 1600. (Micrograph provided by the Regents of University of Michigan Medical School \u00a9 2012)<\/figcaption><\/figure>\n<div class=\"bc-figcaption figcaption\"><\/div>\n<\/div>\n<div id=\"fs-id2327137\" class=\"anatomy interactive um\" data-type=\"note\" data-has-label=\"true\" data-label=\"\">\n<div class=\"bc-figcaption figcaption\"><\/div>\n<p>View the <a href=\"http:\/\/openstax.org\/l\/cardmuscleMG\">University of Michigan WebScope<\/a> to explore the tissue sample in greater detail.<\/p>\n<\/div>\n<p>Intercalated discs are part of the sarcolemma and contain two structures important in cardiac muscle contraction: gap junctions and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_858_2151\">desmosomes<\/a>. A gap junction forms channels between adjacent cardiac muscle fibers that allow the depolarizing current produced by cations to flow from one cardiac muscle cell to the next. This joining is called electric coupling, and in cardiac muscle it allows the quick transmission of action potentials and the coordinated contraction of the entire heart. This network of electrically connected cardiac muscle cells creates a functional unit of contraction called a syncytium. The remainder of the intercalated disc is composed of desmosomes. A desmosome is a cell structure that anchors the ends of cardiac muscle fibers together so the cells do not pull apart during the stress of <a href=\"#fig-ch10_07_02\">individual fibers contracting<\/a>.<\/p>\n<div id=\"fig-ch10_07_02\" class=\"bc-figure figure\">\n<div data-type=\"title\"><\/div>\n<figure id=\"attachment_857\" aria-describedby=\"caption-attachment-857\" style=\"width: 1018px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-857\" src=\"https:\/\/pressbooks.bccampus.ca\/pathology\/wp-content\/uploads\/sites\/1260\/2021\/08\/1020_Cardiac_Muscle-1.jpg\" alt=\"This image shows the structure of the cardiac muscle. A small image of the heart is shown on the top left of the figure and then a magnified view of the cardiac muscle is shown, with the nucleus and the cardiac muscle fiber labeled. A further magnification shows the structure of the intercalated discs with the desmosome and gap junction.\" width=\"1018\" height=\"476\" srcset=\"https:\/\/pressbooks.bccampus.ca\/pathology\/wp-content\/uploads\/sites\/1260\/2021\/08\/1020_Cardiac_Muscle-1.jpg 1018w, https:\/\/pressbooks.bccampus.ca\/pathology\/wp-content\/uploads\/sites\/1260\/2021\/08\/1020_Cardiac_Muscle-1-300x140.jpg 300w, https:\/\/pressbooks.bccampus.ca\/pathology\/wp-content\/uploads\/sites\/1260\/2021\/08\/1020_Cardiac_Muscle-1-768x359.jpg 768w, https:\/\/pressbooks.bccampus.ca\/pathology\/wp-content\/uploads\/sites\/1260\/2021\/08\/1020_Cardiac_Muscle-1-65x30.jpg 65w, https:\/\/pressbooks.bccampus.ca\/pathology\/wp-content\/uploads\/sites\/1260\/2021\/08\/1020_Cardiac_Muscle-1-225x105.jpg 225w, https:\/\/pressbooks.bccampus.ca\/pathology\/wp-content\/uploads\/sites\/1260\/2021\/08\/1020_Cardiac_Muscle-1-350x164.jpg 350w\" sizes=\"auto, (max-width: 1018px) 100vw, 1018px\" \/><figcaption id=\"caption-attachment-857\" class=\"wp-caption-text\">Intercalated discs are part of the cardiac muscle sarcolemma and they contain gap junctions and desmosomes.<\/figcaption><\/figure>\n<div class=\"bc-figcaption figcaption\"><\/div>\n<\/div>\n<p>Contractions of the heart (heartbeats) are controlled by specialized cardiac muscle cells called pacemaker cells that directly control heart rate. Although cardiac muscle cannot be consciously controlled, the pacemaker cells respond to signals from the autonomic nervous system (ANS) to speed up or slow down the heart rate. The pacemaker cells can also respond to various hormones that modulate heart rate to control blood pressure.<\/p>\n<p>The wave of contraction that allows the heart to work as a unit, called a functional syncytium, begins with the pacemaker cells. This group of cells is self-excitable and able to depolarize to threshold and fire action potentials on their own, a feature called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_858_2150\">autorhythmicity<\/a>; they do this at set intervals which determine heart rate. Because they are connected with gap junctions to surrounding muscle fibers and the specialized fibers of the heart\u2019s conduction system, the pacemaker cells are able to transfer the depolarization to the other cardiac muscle fibers in a manner that allows the heart to contract in a coordinated manner.<\/p>\n<p>Another feature of cardiac muscle is its relatively long action potentials in its fibers, having a sustained depolarization \u201cplateau.\u201d The plateau is produced by Ca<sup>++<\/sup> entry though voltage-gated calcium channels in the sarcolemma of cardiac muscle fibers. This sustained depolarization (and Ca<sup>++<\/sup> entry) provides for a longer contraction than is produced by an action potential in skeletal muscle. Unlike skeletal muscle, a large percentage of the Ca<sup>++<\/sup> that initiates contraction in cardiac muscles comes from outside the cell rather than from the SR.<\/p>\n<div class=\"textbox textbox--exercises\">\n<header class=\"textbox__header\">\n<p class=\"textbox__title\">Critical Thinking Exercise<\/p>\n<\/header>\n<div class=\"textbox__content\">\n<p>Answer these questions for yourself:<\/p>\n<ul>\n<li>Consider the function of cardiac muscle cells\n<ul>\n<li>How do the shape, structure, arrangement, size, and number of these cells support their function?<\/li>\n<li>Speculate on the level of cellular change that can affect these cells and their function.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<h2>Section Review<\/h2>\n<p>Cardiac muscle is striated muscle that is found exclusively in the heart. Cardiac muscle fibers are branched, contain a single nucleus, and are joined to one another by intercalated discs. These discs contain gap junctions for depolarization between cells and desmosomes to hold the fibers together when the heart contracts. Contraction in each cardiac muscle fiber is triggered by Ca<sup>++<\/sup> ions in a similar manner as skeletal muscle, but here the Ca<sup>++<\/sup> ions come from sarcoplasmic reticulum (SR) and through voltage-gated calcium channels in the sarcolemma. Pacemaker cells stimulate the spontaneous contraction of cardiac muscle as a functional unit, called a syncytium.<\/p>\n<h1>Review Questions<\/h1>\n<div class=\"h5p\">\n<div id=\"h5p-19\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-19\" class=\"h5p-iframe\" data-content-id=\"19\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"cloned cardiac tissue self test\"><\/iframe><\/div>\n<\/div>\n<\/div>\n<div class=\"pdf\">\n<p><strong>1. Finish the following sentence. Cardiac muscles differ from skeletal muscles in that they:<\/strong><\/p>\n<ul>\n<li>Are striated<\/li>\n<li>Utilize aerobic metabolism<\/li>\n<li>Contain myofibrils<\/li>\n<li>Contain intercalated discs<\/li>\n<\/ul>\n<p><strong>2. Finish the following sentence. If cardiac muscle cells were prevented from undergoing aerobic metabolism, they ultimately would:<\/strong><\/p>\n<ul>\n<li>Undergo glycolysis<\/li>\n<li>Synthesize ATP<\/li>\n<li>Stop contracting<\/li>\n<li>Start contracting<\/li>\n<\/ul>\n<p><strong>3. What would be the drawback of cardiac contractions being the same duration as skeletal muscle contractions?<\/strong><\/p>\n<p><strong>4. How are cardiac muscle cells similar to and different from skeletal muscle cells?<\/strong><\/p>\n<div class=\"textbox\">\n<h2>Answer Key<\/h2>\n<ol>\n<li>Contain intercalated discs<\/li>\n<li>Stop contracting<\/li>\n<li>An action potential could reach a cardiac muscle cell before it has entered the relaxation phase, resulting in the sustained contractions of tetanus. If this happened, the heart would not beat regularly.<\/li>\n<li>Cardiac and skeletal muscle cells both contain ordered myofibrils and are striated. Cardiac muscle cells are branched and contain intercalated discs, which skeletal muscles do not have.<\/li>\n<\/ol>\n<\/div>\n<\/div>\n<p>&nbsp;<\/p>\n<h1>Adaption<\/h1>\n<p>This chapter is adapted from the following text:<\/p>\n<p><a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/19-2-cardiac-muscle-and-electrical-activity\" target=\"_blank\" rel=\"noopener\">Cardiac muscle and electrical activity<\/a>\u00a0<strong>in\u00a0<\/strong><a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\">Anatomy and Physiology<\/a>\u00a0by\u00a0OSCRiceUniversity\u00a0is licensed under a\u00a0<a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">Creative Commons Attribution 4.0 International License<\/a><\/p>\n<div class=\"media-attributions clear\" prefix:cc=\"http:\/\/creativecommons.org\/ns#\" prefix:dc=\"http:\/\/purl.org\/dc\/terms\/\"><h2>Media Attributions<\/h2><ul><li about=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/19-2-cardiac-muscle-and-electrical-activity\"><a rel=\"cc:attributionURL\" href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/19-2-cardiac-muscle-and-electrical-activity\" property=\"dc:title\">414c_Cardiacmuscle-1<\/a>  &copy;  OSCRiceUniversity    is licensed under a  <a rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY (Attribution)<\/a> license<\/li><li about=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/19-2-cardiac-muscle-and-electrical-activity\"><a rel=\"cc:attributionURL\" href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/19-2-cardiac-muscle-and-electrical-activity\" property=\"dc:title\">1020_Cardiac_Muscle-1<\/a>  &copy;  OSCRiceUniversity    is licensed under a  <a rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY (Attribution)<\/a> license<\/li><\/ul><\/div><div class=\"glossary\"><span class=\"screen-reader-text\" id=\"definition\">definition<\/span><template id=\"term_858_2152\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_858_2152\"><div tabindex=\"-1\"><p>part of the sarcolemma that connects cardiac tissue, and contains gap junctions and desmosomes<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_858_2151\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_858_2151\"><div tabindex=\"-1\"><p>cell structure that anchors the ends of cardiac muscle fibers to allow contraction to occur<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_858_2150\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_858_2150\"><div tabindex=\"-1\"><p>heart\u2019s ability to control its own contractions<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><\/div>","protected":false},"author":1232,"menu_order":4,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":["j-gordon-betts","kelly-a-young","james-a-wise","eddie-johnson","brandon-poe","dean-h-kruse","oksana-korol","jody-e-johnson","mark-womble","peter-desaix"],"pb_section_license":"cc-by"},"chapter-type":[],"contributor":[70,71,69,66,68,73,67,74,72,75],"license":[52],"class_list":["post-858","chapter","type-chapter","status-publish","hentry","contributor-brandon-poe","contributor-dean-h-kruse","contributor-eddie-johnson","contributor-j-gordon-betts","contributor-james-a-wise","contributor-jody-e-johnson","contributor-kelly-a-young","contributor-mark-womble","contributor-oksana-korol","contributor-peter-desaix","license-cc-by"],"part":324,"_links":{"self":[{"href":"https:\/\/pressbooks.bccampus.ca\/pathology\/wp-json\/pressbooks\/v2\/chapters\/858","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.bccampus.ca\/pathology\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.bccampus.ca\/pathology\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/pathology\/wp-json\/wp\/v2\/users\/1232"}],"version-history":[{"count":23,"href":"https:\/\/pressbooks.bccampus.ca\/pathology\/wp-json\/pressbooks\/v2\/chapters\/858\/revisions"}],"predecessor-version":[{"id":9065,"href":"https:\/\/pressbooks.bccampus.ca\/pathology\/wp-json\/pressbooks\/v2\/chapters\/858\/revisions\/9065"}],"part":[{"href":"https:\/\/pressbooks.bccampus.ca\/pathology\/wp-json\/pressbooks\/v2\/parts\/324"}],"metadata":[{"href":"https:\/\/pressbooks.bccampus.ca\/pathology\/wp-json\/pressbooks\/v2\/chapters\/858\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.bccampus.ca\/pathology\/wp-json\/wp\/v2\/media?parent=858"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/pathology\/wp-json\/pressbooks\/v2\/chapter-type?post=858"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/pathology\/wp-json\/wp\/v2\/contributor?post=858"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/pathology\/wp-json\/wp\/v2\/license?post=858"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}