When a man has achieved a sufficient level of stimulation, ejaculation begins. At that point, under the control of the sympathetic nervous system, semen containing sperm is produced (emission). The semen is ejected through the urethra with rhythmic contractions. These rhythmic

When a man has achieved a sufficient level of stimulation, ejaculation begins. At that point, under the control of the sympathetic nervous system, semen containing sperm is produced (emission). The semen is ejected through the urethra with rhythmic contractions. These rhythmic contractions are part of the male orgasm. They are generated by the bulbospongiosus muscle under the control of a spinal reflex at the level of the spinal nerves S2-4 via the pudendal nerve. The typical male orgasm lasts several seconds.