Erection of the penis results from which of the following nervous system activities?

• A. Parasympathetic stimulation
• B. Somatic motor stimulation
• C. Sympathetic stimulation
• D. Inhibition of the enteric nervous system

Answer: (A)

Verified step by step guidance

1. Understand the role of the autonomic nervous system in regulating physiological functions. The autonomic nervous system is divided into the sympathetic and parasympathetic divisions, each responsible for different activities in the body.
2. Recall that the parasympathetic nervous system is primarily involved in 'rest and digest' activities, including processes that promote relaxation and increased blood flow to certain areas of the body.
3. Recognize that an erection is caused by increased blood flow to the penile tissue, which is facilitated by the relaxation of smooth muscle in the blood vessels. This process is mediated by parasympathetic stimulation.
4. Differentiate the roles of the other options: Sympathetic stimulation is typically associated with 'fight or flight' responses, somatic motor stimulation controls voluntary muscle movements, and the enteric nervous system regulates gastrointestinal functions.
5. Conclude that parasympathetic stimulation is the correct answer because it promotes vasodilation and increased blood flow to the penis, leading to an erection.