Also found in: Dictionary, Thesaurus, Legal, Encyclopedia.
If the testes are removed (castration, bilateral orchiectomy) before puberty, the male is sterile and will never develop all the adult male secondary sex characters. If they are removed after puberty, the male becomes sterile and his secondary sex characters will diminish unless he receives injections of male hormones. With aging, there is a gradual decrease in the production of testosterone.
In the fetus in utero, the testes lie close to the kidneys. During approximately the seventh month of fetal life, the testes begin to descend through the abdominal wall at the groin and enter the scrotum. As they descend they are accompanied by blood vessels, nerves, and ducts, all contained within the spermatic cord. The passageway through which the testis and spermatic cord descend is called the inguinal canal. Failure of a testis to descend into the scrotum is called cryptorchidism.
The testis is divided internally into about 250 compartments or lobules, each of which contains one to three small convoluted tubules, within which spermatozoa are produced. When mature, the spermatozoa leave the tubules and enter the epididymis (situated on top of and behind each testis), where maturation is completed. The spermatozoa are stored in the epididymis until such time as they are mixed in the semen and ejaculated during coitus. (See also reproduction and male reproductive organs.)
In order to ensure early detection of cancer of the testis, men are urged to conduct a monthly self-examination of the testes. The self-examination involves the use of both hands to examine each of the testes. The index and middle fingers are placed below the testis and the thumbs on top. With a gentle motion each testis is rolled between the thumbs and fingers to discover any lump (usually about the size of a pea), thickening, or change in the consistency of the tissues. It is important that the man become familiar with the feel of the epididymis so that he doesn't confuse this normal structure with an abnormal lump. Should a lump or any other abnormality be found, a doctor should be consulted immediately. The American Cancer Society publishes several pamphlets that explain the procedure for testicular self-examination and give additional information on testicular cancer. Diagnosis of testicular cancer is confirmed by biopsy of the suspect testis. There are three stages of classification for malignancy of the testis: Stage I: the tumor is confined to the affected testis; Stage II: the malignancy has spread to the regional lymph nodes; and Stage III: there is metastasis to other organs, such as the lung and liver.
Treatment of testicular cancer (simple orchiectomy for Stage I malignancy) may or may not render the patient impotent and sterile. If there is no metastasis, only the affected testis need be removed. The remaining testis will retain its normal function and the patient should be able to have normal sexual intercourse and be fertile. However, if more radical surgery and radiation therapy are called for and both testes and the lymph nodes are dissected, and if there has been no damage to nerves during surgery, the patient may be able to have sexual intercourse but no seminal fluid will be emitted. A young man who is looking forward to having children may consider banking his sperm prior to surgery so that he might father children by artificial insemination.
tes·tes(tes'tis, -tēz), [TA]
See also: appendix testis.
testis/tes·tis/ (tes´tis) pl. tes´tes [L.] the male gonad; either of the paired egg-shaped glands normally situated in the scrotum, in which the spermatozoa develop. Specialized interstitial cells (Leydig cells) secrete testosterone.
testisEither of the pair of male sexual organs, which are located in the scrotum and produce sperm—beginning in puberty and then throughout life—as well as testosterone.
tes·tis, pl. testes (tes'tis, -tēz) [TA]
See also: appendix of testis
Synonym(s): orchis [TA] , didymus, testicle.
testis(tes'tis) plural.testes [L.]
Each is an ovoid body about 4 cm long and 2 to 2.5 cm in width and thickness, enclosed within a dense inelastic fibrous tunica albuginea. The testis is divided into numerous lobules separated by septa, each lobule containing one to three seminiferous tubules within which the spermatozoa are produced by meiosis. The lobules lead to straight ducts that join a plexus, the rete testis, from which 15 to 20 efferent ducts lead to the epididymis. The epididymis leads to the ductus deferens, through which sperm are conveyed to the urethra. Between the seminiferous tubules are the interstitial cells (cells of Leydig), which secrete testosterone. Within the tubules are sustentacular cells, which secrete inhibin. The testes are suspended from the body by the spermatic cord, a structure that extends from the inguinal ring to the testis and contains the ductus deferens, testicular vessels (spermatic artery, vein, lymph vessels), and nerves.
Hyperfunction (hypergonadism) may cause early maturity such as large sexual organs with early functional activity and increased growth of hair. Hypofunction (hypogonadism) is indicated by undeveloped testes, absence of body hair, high-pitched voice, sterility, smooth skin, loss of sexual desire, low metabolism, and eunuchoid or eunuch body type.
descent of testis
testisOne of the two male gonads, suspended in the scrotum by the spermatic cord. The testis, or testicle, contains the long, coiled seminiferous tubules in which the SPERMATOZOA are formed. Between the tubules are cells that secrete testosterone and other masculinizing steroid hormones and oestrogens.
testis(pl. testes) the organ of the male animal, producing the male gametes, or sperms. It also produces ANDROGENS - male Dictionary of Biology 2005 9.5 2/6 /05 3:46 pm Page 465 sex hormones. See SCROTUM, SEMINIFEROUS TUBULES, GERMINAL EPITHELIUM, SERTOLI CELLS.
testisthe male gonad, the site of spermatogenesis, whence sperm are discharged via the vas deferens into the urethra at ejaculation. This and also testicular endocrine function (secretion of testosterone and related hormones) are under the control of gonadotrophic hormones from the anterior pituitary, and in turn of the hypothalamus.
Patient discussion about testis
Q. Has anyone ever had Epididymitis? I was just diagnosed with it and want to know what to expect. Thanks
slight pain,tenderness,problems with urination,and not
urinating very often,feel as if i"m not completing my
urination,feels like i have a bladder infection,with
an epididymis infection,this makes the 7th time i"ve
had this,i"d like to know why i keep getting it??? and
will it ever stay away??? is there a complete cure?
would a vasecemy cure it???