The testicles are the two male glands which are suspended from the groin by the spermatic cords, and are supported and enclosed by the scrotum. Each gland measured about 1 1/2 inches in length, 1 inch width and about 3/4 in thickness from side to side. The testicle is joined to the spermatic cord by way of the epididymis which is a coiled duct Lying at the upper portion of the testicle. When uncoiled this duct measures 20 feet in length. The function of the testicles is to produce spermatozoa and the male sex hormone; See figure, next page. If both testicles are removed before puberty, secondary sex characteristics fail to develop, due to the absence of testosterone. The skin remains smooth, the voice is high-pitched, fat develops around the breasts and buttocks, and the pubic hair is scanty. Erections are feeble, and no ejaculation occurs. The individual is timid, lacks ambition, normal combativeness and aggressiveness. Such an individual is known as a eunuch. Eunuchoidism usually results from failure of development of testes, which is usually secondary to a pituitary disorder.
In early fetal life both the ovaries and the testicles lie in front of and below the kidneys. During fetal growth they descend. The ovaries finally lodge on the side wall of the pelvic cavity. The testicles normally continue downward and descend through and out of the abdomen in the region of the groin to the scrotum. This descent may be arrested along any portion of this pathway, and one or both testicles may remain in the abdominal cavity, in its wall or groin. The condition is known as cryptorchidism. Men with undescended testicles because sperm gets too warm, are sterile but are sexually normal otherwise. The situation is corrected by an operation in which the undescended testicles is brought down to its normal scrotal position. This operation is best done at or shortly after puberty.
In some cases glandular injections will cause the testicle to descend without operative interference.
Diseases affecting the testicles are tumors, which are rare and infections.
The testes are controlled by hormones secreted from the anterior pituitary. Two pituitary hormones are involved in regulation of testicular function, one for the endocrine component and the other for the gametogenic component. Luteining hormone, LH acts on leydig cells to stimulate testosterone secretion and follicle-stimulating hormone or FSH acts on the seminiferous tubules to promote spermatogenesis. (See figures A,B, and C).