ABSTRACT
There are two phases of ejaculation. During the initial phase coined “emission,” semen is deposited into the posterior urethra. Emission is under the control of the sympathetic nervous system: afferent stimuli from the genitalia travel via the pudendal nerve to the cerebral cortex. Efferent impulses travel by way of the anterolateral columns to the sympathetic nerves, T12 to L3. Through the hypogastric nerve, impulses cause the contraction of the vas deferens, seminal vesicles, and prostate gland, as well as bladder neck closure. These two simultaneous events governed by the sympathetic nervous system result in emission of the ejaculate into the posterior urethra.
