Cardiovascular: How does the SNS alter a pacemaker action potential? Give the mechanism.
Cardiovascular: How does the SNS alter a pacemaker action potential? Give the mechanism.
The sympathetic nervous system (SNS) influences cardiovascular outcomes such as heart rate acceleration, more significant cardiac contractions, decreased venous capacitance, and decreased peripheral vasoconstriction.
The electrical impulses for cardiac contractions originate in the SA node, a small collection of specialized cells found in the right atrium (the root of the IVC). The electrical impulses travel through the atria's walls, causing them to contract and force blood from the atria into the ventricles. The SA node controls the heartbeat's pace and tempo.
When the heart rate rises, the autonomic nervous system (ANS) increases sympathetic (SN) outflow to the SA node. In addition, the ANS would send signals to block vagal impulses concurrently. In order to raise the heart rate, the vagal tone must be inhibited. As previously stated, vagal tone modulates the action of sympathetic nerve activity at the SA node.
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