Why does the penis ejaculate?

Male masturbation is also called masturbation, which means that men hold their genitals with their hands and move them up and down to imitate the movements of sexual intercourse. This can bring pleasure to men and stimulate them to ejaculate. Ejaculation is mainly due to the reflex after the male reproductive organs are stimulated during sexual intercourse. When the stimulation reaches the point of excitement, reflexive ejaculation will occur. So why does masturbation cause ejaculation?

Ejaculation, a basic biological term, is the reflex action of male animals to eject semen during sexual intercourse. For humans, ejaculation is a series of coordinated actions of various parts of the reproductive system, and semen is ejected from the penis.

It consists of a two-step spinal reflex, the primary of which is centered in the lumbosacral spinal cord, with sensory impulses transmitted by touch receptors in the glans penis. The neurophysiology of ejaculation is only partially understood. Studies have shown that dopaminergic systems promote ejaculation while serotonergic systems inhibit ejaculation.

The primary neural mechanism of ejaculation is somatic innervation, but it also involves nerves and fibers from the autonomic nervous system in the vagina. The autonomic branches of the parasympathetic nervous system primarily control erectile function, while the sympathetic and somatic branches primarily control emission and ejaculation.

The first step of ejaculation is that the sympathetic nerves send out impulses to cause the smooth muscles of the vas deferens and seminal vesicles to contract, thereby transferring the semen in the vas deferens and seminal vesicles to the urethra; the second step is to use the impulses of the pudendal nerves to contract the transverse muscles at the root of the corpus cavernosum of the penis, thereby ejecting the semen in the urethra. The excitement of the higher parts of the brain also acts on the erection center and ejaculation center of the spinal cord through the descending pathway. Normal human sexual excitement stimulation comes from various senses and affects the spinal reflex activities through the brain.

Ejaculation is a complex process that includes erection, ejaculation, ejaculation and orgasm. Erection is due to the swelling and hardening of the penis, and its primary nerve innervation comes from the sacral nerve plexus and the pelvic visceral nerves or erectile nerves. Ejaculation involves collecting semen before ejaculation and transporting it to the prostatic part of the urethra. With the closure of the bladder neck and distal urethral sphincter, the prostatic part of the urethra becomes a reservoir of semen. This will induce ejaculation, that is, the rhythmic ejection of semen through the urethra. The participation of the skeletal muscles of the perineum is essential in this process. Orgasm is a brain-involved, usually pleasurable event and is closely related to ejaculation.

The neurophysiology of ejaculation is only partially understood. Research suggests that dopaminergic systems promote ejaculation while serotonergic systems inhibit ejaculation. The primary neural mechanism of ejaculation is somatic innervation, but it also involves nerves and fibers from the autonomic nervous system in the vagina; the autonomic branches of the parasympathetic nervous system primarily control erectile function while the sympathetic and somatic branches primarily control firing and ejaculation.