This site is intended for healthcare professionals

Go to /sign-in page

You can view 5 more pages before signing in

Gap junctions

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

A gap junction is a specialised channel of transport and communication for small molecules and ions between the cytoplasm of two closely apposed cells.

Electron microscopy reveals the two cell membranes to be separated by only 1-2 nanometres at the point where the gap junctions are sited. Each membrane has a large number of small protein channels termed connexons. Individual connexons of both cells are joined to each other to create a communicating tunnel which spans the membrane gap. The internal diameter of the passage is about 2 nanometres.

Each connexon on each membrane is made up of 6 polypeptide chain subunits which span the membrane.

Electrophysiological studies have shown low electrical resistance for the cell when there are abundant gap junctions. Injection of low molecular weight dyes results in rapid spread between cells. Therefore, gap junctions provide a pathway by which small molecules and ions can rapidly move down concentration gradients between cells.

Gap junctions are evident in epithelia and smooth muscle. They permit all of the cells to act as a synctium. However, if continued passive transport is detrimental to the synctium, individual gap junctions can be rapidly close.


Create an account to add page annotations

Add information to this page that would be handy to have on hand during a consultation, such as a web address or phone number. This information will always be displayed when you visit this page

The content herein is provided for informational purposes and does not replace the need to apply professional clinical judgement when diagnosing or treating any medical condition. A licensed medical practitioner should be consulted for diagnosis and treatment of any and all medical conditions.

Connect

Copyright 2024 Oxbridge Solutions Limited, a subsidiary of OmniaMed Communications Limited. All rights reserved. Any distribution or duplication of the information contained herein is strictly prohibited. Oxbridge Solutions receives funding from advertising but maintains editorial independence.