Question

erection of the penis results from ______.

1. a sympathetic reflex
2. parasympathetic activation of the bulbourethral glands
3. dilation of the veins in the penis
4. a parasympathetic reflex

Explanation:

To determine the cause of penile erection, we analyze each option:

• Option 1: Sympathetic reflex is incorrect as erection is parasympathetic - mediated.
• Option 2: Bulbourethral glands secrete pre - ejaculatory fluid, not cause erection.
• Option 3: Erection involves dilation of arteries (not veins) in the penis.
• Option 4: Penile erection is a parasympathetic reflex. Parasympathetic activation leads to arterial dilation in the penis, allowing blood to fill erectile tissues.

Answer:

1. a parasympathetic reflex