Question

Does sympathetic or parasympathetic nervous system cause relaxation of the urinary sphincter?

1) Sympathetic nervous system
2) Parasympathetic nervous system
3) Both sympathetic and parasympathetic nervous system
4) Neither sympathetic nor parasympathetic nervous system

Answer 1

The relaxation of the urinary sphincter is caused by the 2) parasympathetic nervous system.

Step-by-step explanation:

During urination, the parasympathetic preganglionic neurons in the sacral spinal cord release acetylcholine onto the postganglionic neurons, which in turn cause the relaxation of the involuntary internal urethral sphincter. This allows urine to flow out of the bladder.

On the other hand, the sympathetic nervous system is responsible for preparing the body for emergencies or stressful situations, and it does not directly influence the relaxation of the urinary sphincter. So therefore the parasympathetic nervous system causes relaxation of the urinary sphincter. The correct answer is 2) parasympathetic nervous system.