When the parasympathetic nervous system is activated, what happens to the heart rate and blood vessels?

When the parasympathetic nervous system is activated, the primary role is to promote a state of rest and relaxation within the body. This is often referred to as the "rest and digest" system, contrasting with the "fight or flight" response of the sympathetic nervous system.

Specifically, the activation of the parasympathetic nervous system leads to a decrease in heart rate. This is achieved through the vagus nerve, which releases neurotransmitters that slow down heart function, allowing for a more restful state. In addition to this reduction in heart rate, blood vessels also undergo dilation. This dilation allows for improved blood flow to areas of the body that are essential for digestion and recovery, enhancing nutrient absorption and other restorative functions.

Overall, the response of decreased heart rate and dilated blood vessels reflects the calming effects of the parasympathetic nervous system, focusing on promoting relaxation and recovery rather than the stress response associated with increased heart rate and blood pressure.