Comprehensive Osteopathic Medical Licensing Examination (COMLEX USA) Practice

What is the effect of the sympathetic nervous system on male sex organs?

1. Erection

2. Ejaculation

3. Arousal

4. Decrease in libido

The correct answer is: Ejaculation

The sympathetic nervous system plays a critical role in male sexual function, specifically in the process of ejaculation. When stimulated, the sympathetic nervous system triggers a series of physiological responses that culminate in the expulsion of semen from the reproductive tract. This process involves the contraction of smooth muscle in the vas deferens, seminal vesicles, and prostate, coordinated through sympathetic innervation. During ejaculation, there are also increases in heart rate and blood pressure mediated by the sympathetic system, emphasizing its role in the final stages of sexual response, rather than the initial phases such as erection or arousal, which are primarily governed by parasympathetic activity. In this context, while the sympathetic nervous system does indirectly influence aspects of libido and arousal through its broader effects on mood and physiology, it is specifically responsible for the mechanics of ejaculation itself, making this option the most appropriate response.