Skip to main content Accessibility help
×
Hostname: page-component-5d59c44645-mrcq8 Total loading time: 0 Render date: 2024-03-01T05:47:44.658Z Has data issue: false hasContentIssue false

2 - Cardiac membrane structure and function

from Part I - Molecular, cellular, and integrative mechanisms determining cardiovascular development

Published online by Cambridge University Press:  10 May 2010

Warren W. Burggren
Affiliation:
University of Nevada, Las Vegas
Bradley B. Keller
Affiliation:
University of Rochester, New York
Get access

Summary

Cardiac function is critically dependent on the movement of ions across membranes. Contraction of the heart begins when an action potential depolarizes the plasma membrane of the myocyte, the sarcolemma. Depolarization is caused by sequential inward currents of sodium ions and calcium ions. The slow inward calcium current enters through voltagegated channels in the sarcolemma and serves several purposes. First, this current supplies a small amount of the activator calcium for binding to troponin C. Second, the sarcoplasmic reticulum (SR) takes up a considerable portion of this calcium, where it forms part of the internal store for release in subsequent contractions. Finally, this calcium triggers the release of a large amount of calcium from the SR. The released SR calcium initiates contraction by binding to troponin C, resulting in formation of cross-bridges between the myosin head and actin. Relaxation begins with the removal of calcium from the myofilaments, which is mediated primarily by the SR calcium pump but also by the Na+-Ca2+ exchanger. Removal of calcium from the myofilaments results in the breaking of actin-myosin cross-bridges and return to the resting state.

Important changes in the structure and function of cardiac membranes occur during maturation of the mammalian heart (and probably in all vertebrate hearts). These changes result in significant age-related differences in myocardial function. This chapter discusses recent work that has increased our understanding of developmental changes in cardiac membranes and of the impact of these changes on myocardial performance.

Type
Chapter
Information
Development of Cardiovascular Systems
Molecules to Organisms
, pp. 18 - 26
Publisher: Cambridge University Press
Print publication year: 1998

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Save book to Kindle

To save this book to your Kindle, first ensure coreplatform@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.

Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Available formats
×

Save book to Dropbox

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.

Available formats
×

Save book to Google Drive

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.

Available formats
×