What is not one of the roles of the parasympathetic nervous system?

Complete question:

Question: What is not one of the roles of the parasympathetic nervous system?

a) increases digestive functions

b) maintains resting heart rate

c) stimulating urination

d) controls the diameter of blood vessels

Answer:

d) controls the diameter of blood vessels

Explanation:

The activated parasympathetic nervous system is mainly associated with the rest and digest activities. This division of the autonomic nervous system triggers the digestive glands to release their secretions and stimulate the contractions of smooth muscles of the digestive tract to upregulate the processes of digestion and absorption of nutrients. In this way, the parasympathetic nervous system restores and conserves the energy of the body. It has no effect on the diameter of blood vessels.

The sympathetic nervous system triggers constriction of blood vessels that supply blood to kidneys and digestive tract during emergency conditions. It also dilates the blood vessels that supply blood to skeletal muscles, cardiac muscles and liver to facilitate increased blood supply to these tissues.