Wednesday, March 19, 2014

What is a Gap Junction?Please give a definition and example.

A Gap Junction is a direct connection between two separate
cells. It allows molecules to pass between the two cells. The Gap Junction, also called
a Nexus, is formed from six proteins called Connexins. The Connexins form a bridge with
a sphincter than can open and close. The importance of the Gap Junction is that it
allows transmission of electrical signals and molecules between cells, instead of being
closed off by the cell membranes.


An example of Gap
Junctions in action is the Heart. Instant communication is key; the Gap Junctions in the
Heart's cellular tissue enable each cell to contract at the same time. Without the
signals passing directly through the cell membranes, the cells would contract
individually and likely cause an irregular heartbeat, which can lead to a heart attack.
The speed and accuracy of the Gap Junction transmission is key to a healthy heartbeat.
Cells naturally share a small amount of electricity during their normal function, but
large-scale, coordinated sharing must occur across Gap Junctions to be
effective.

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