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Showing posts from June, 2006

Pace Maker Tissue and Heart

The above picture shows the different regions of the heart. Heart is a muscular organ in our body, that is made of four chambers in humans as we as in all mammals. In fishes and amphibians though, it has been observed to be of three chambers. The muscles are of special type, called the cardiac muscles. They have inter-fibrillar branches that simply acts as functional synctitium, having gaph junctions. This helps the heart muscles to contract circumferentially as a whole, as the pace maker stimulus passes down the line of action.
Heart is autorhythmic in nature. It means that it beats on its own, and that too in a rythmical pattern. This rythmical pattern is enabled by some special kinds of tissues called the pace maker tissues. There are four different types found within the cardiac muscular mass:
1) Sino Atrial Node (SAN)
2) Atrio Ventricular Node (AVN)
3) Bundle of His
4) Purkinjee Fibers.
The figure in the adjacent plate shows the orientation of these tissues. The SAN is located at the e…