Question

Describe and/or draw the pathway by which the sympathetic nervous system regulates the heart.

Answer 1

There are two nerves which links the cardio vascular centre in the medulla oblangata of brain with the SA nide of heart. They are ,

• The sympathetic nervous system ( or also called as accelerator nerve
• The para sympathetic nervous system ( or also called as vagus nerve)

In sympathetic nervous system when the accelerator nerve is stimulated ,it release neurotransmitter at the SA node to increase heart rate. During this a numerous sympathetic nerves also links to the walls of two ventricle where they increase the force of contraction of these chambers.

In parasympathetic nervous system when the vagus nerve is stimulated, it releases neurotransmitters at the SA node to decrease heart rate.

1. Parasympathetic nerve or vagus nerve

2. Sympathetic nerve or accelerator nerve