Ejaculation is a nervous reflex caused by stimulation of the genitals, by setting in awakening of the erotogenic cerebral centers, or by excessive repletion of the spermatic way.

Contraction of the musculature of the vas deferens causes an increase in pressure in the spermatic way and sperm is projected in the urethra through ejaculatory ducts.

After a period of three days abstinence, volume of ejaculated semen is from two to four cubic-centimetres.

When sperm is emitted in the urethra,into the prostate, the bladder neck  closes automatically avoiding the passage of secretions into the bladder, the only exit being outside.

If  male hormones' production decreases at the time of andropause disease, the volume of sperm decreases gradually until disappearing, but the administration of male hormones restores the production of sperm.

Delayed ejaculation     Premature ejaculation