Testis

: The testis (or testicle) is the male sex gland. A pair of testes are located behind the penis in a pouch of skin called the scrotum. The testes have two functions: one in regard to sperm and the other in regard to hormones. The testes produce and store sperm. The testes are also the body's main source of male hormones (testosterone) which control the development of the reproductive organs and other male characteristics, such as body and facial hair, low voice, and wide shoulders. The word "testis" is a Latin word that means "witness." In ancient times, a person providing testimony might validate it by holding the scrotum, his or another man's. "And the servant put his hand under the thigh of Abraham his master, and sware to him concerning the matter." (Genesis 24:9)

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One of the two male reproductive glands, located in the cavity of the scrotum. SEE ALSO: appendix t.. SYN: didymus, genital gland (1), male gonad, orchis, testicle, testiculus. [L.]

- abdominal t. an undescended t. that has never descended from the retroperineal/abdominal origin through the internal inguinal ring.

- cryptorchid t. SYN: undescended t..

- ectopic t. a variant of undescended t. wherein testicular position is outside the usual pathway of descent. SEE ALSO: t. ectopia.

- movable t. SYN: retractile t..

- peeping t. an undescended t. that migrates back and forth at the internal inguinal ring.

- retractile t. a condition in which there is a tendency of the t. to ascend to the upper part of the scrotum or into the inguinal canal, as contrasted with an undescended t.. SYN: movable t., pseudocryptorchism.

- undescended t. a t. that has failed to descend into the scrotum; there are palpable and nonpalpable (impalpable) variants. SYN: cryptorchid t..

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tes·tis 'tes-təs n, pl tes·tes 'tes-.tēz a typically paired male reproductive gland that usu. consists largely of seminiferous tubules from the epithelium of which spermatozoa develop, that contains androgen-secreting Leydig cells in the interstitial tissue, that corresponds to the ovary of the female and in craniate vertebrates develops from the genital ridges of the embryo, and that in most mammals descends into the scrotum before the attainment of sexual maturity and in many cases before birth

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n. (pl. testes)

either of the pair of male sex organs that produce spermatozoa and secrete the male sex hormone androgen under the control of gonadotrophin from the pituitary gland. The testes of the fetus form within the abdomen but descend into the scrotum in order to maintain a lower temperature that favours the production and storage of spermatozoa. The bulk of the testis is made up of long convoluted seminiferous tubules, in which the spermatozoa develop (see spermatogenesis). The tubules also contain Sertoli cells, which may nourish developing sperm cells. Spermatozoa pass from the testis to the epididymis to complete their development. The interstitial (Leydig) cells, between the tubules, are the major producers of androgen.

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tes·tis (tesґtis) pl. tesґtes [L.] [TA] testicle: the male gonad; either of the paired egg-shaped glands normally situated in the scrotum. Each testis is surrounded by an outer mesothelial layer (tunica vaginalis) and an inner white capsule (tunica albuginea), and is composed of compartments (lobuli testis) containing the seminiferous tubules, in which the spermatozoa are produced. Specialized interstitial cells (Leydig cells) secrete testosterone. Called also orchis [TA alternative] and testiculus.

Testis and surrounding structures.