Sinoatrial Node of the Heart
What is sinoatrial node and how does it affect the heart?
Your heart contains a type of muscle cell called cardiac (heart) muscle.
These cells are penetrated by nerves from the nervous system. This causes
them to contract at a regular rate to pump the blood through the heart and
the body. There is a patch of muscle cells in the upper part of the right
atrium that is capable of contracting by itself and a little faster than the
other cells in the area. This is called the SA node. Because it contracts
first, it is called the pacemaker of the heart because it sets the pace of
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Update: June 2012