Male Reproductive Physiology

Male Reproductive Physiology

For 13-15 years of age, the testes begin to function under the influence of pituitary secretion. Testes produce the hormone testosterone, which provides the appearance of secondary sex characteristics.
Testosterone, once started, will continue throughout life. Simultaneously with testosterone production and manufacturing start spermiilor, who start their road to genital tract.

Spermiile need about 2, 5 months to travel along the road that separates the testicles are formed by extreme urethra which are eliminated during ejaculation. They cross the channel end of the epididymis, vas deferens and seminal vesicles remains stored before being eliminated during sex. Then spermiile mix with prostatic secretions and semen form that eliminates the vagina. From there, it passes into the uterus and fallopian tube farther in its upper third, where fertilization can take place.

Semen contains proteins, carbohydrates, organic acids: citric acid, ascorbic acid and hormones that ensure survival spermiilor substances.

Man's whole life, from puberty until death, testicles spermii factory in extremely large number. This production slows or stops spermiilor only in case of serious illness or a severe state of fatigue.
So while a woman produces one egg per month than a man during an ejaculation eliminate about 350 million spermii. Also, while usually the woman is only fertile during ovulation, the man is fertile throughout life, from puberty.
 Male Reproductive Physiology
Erection and ejaculation

An erection is caused by different types of excitations physical, mental or sensory sending information to a reflex center located in the spinal cord. During erection, the corpora cavernosa fill with blood and veins that allow blood to flow back into the sea close. Penis increases in volume, change their position, perpendicular to the abdomen becomes rigid, thus can penetrate the woman's vagina.
Male Reproductive Physiology
Ejaculation occurs when the penis is erect, is caused by strong contractions of the muscles of the penis. These contractions cause evacuation of accumulated sperm to the urethra seminal vesicles.
Semen is expelled in several jets of decreasing intensity. Corresponding to each ejaculate sperm count is 1-4 cm 3, each sperm contains 50-100 cm 3 million spermii.

Erection and ejaculation can occur at night, unconsciously (involuntarily). Nocturnal ejaculations, common during adolescence, is normal and should not be a reason for concern.