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A testicle or testis is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testosterone. Testosterone release is controlled by the anterior pituitary luteinizing hormone, whereas sperm production is controlled both by the anterior pituitary follicle-stimulating hormone and gonadal testosterone.
Testicular torsion occurs when the spermatic cord twists, cutting off the blood supply to the testicle. The most common symptom in children is sudden, severe testicular pain. The testicle may be higher than usual in the scrotum and vomiting may occur. In newborns, pain is often absent and instead the scrotum may become discolored or the testicle may disappear from its usual place.
Testicular cancer is cancer that develops in the testicles, a part of the male reproductive system. Symptoms may include a lump in the testicle, or swelling or pain in the scrotum. Treatment may result in infertility.
Cryptorchidism is the absence of one or both testes from the scrotum. The word is from Greek κρυπτός 'hidden' and ὄρχις 'testicle'. It is the most common birth defect of the male genital tract. About 3% of full-term and 30% of premature infant boys are born with at least one undescended testis. However, about 80% of cryptorchid testes descend by the first year of life, making the true incidence of cryptorchidism around 1% overall. Cryptorchidism may develop after infancy, sometimes as late as young adulthood, but that is exceptional.
A hydrocele testis is an accumulation of clear fluid within the cavum vaginale, the potential space between the layers of the tunica vaginalis of the testicle. A primary hydrocele causes a painless enlargement in the scrotum on the affected side and is thought to be due to the defective absorption of fluid secreted between the two layers of the tunica vaginalis. A secondary hydrocele is secondary to either inflammation or a neoplasm in the testis.
Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testis. This process starts with the mitotic division of the stem cells located close to the basement membrane of the tubules. These cells are called spermatogonial stem cells. The mitotic division of these produces two types of cells. Type A cells replenish the stem cells, and type B cells differentiate into primary spermatocytes. The primary spermatocyte divides meiotically into two secondary spermatocytes; each secondary spermatocyte divides into two equal haploid spermatids by Meiosis II. The spermatids are transformed into spermatozoa (sperm) by the process of spermiogenesis. These develop into mature spermatozoa, also known as sperm cells. Thus, the primary spermatocyte gives rise to two cells, the secondary spermatocytes, and the two secondary spermatocytes by their subdivision produce four spermatozoa and four haploid cells.
Orchiopexy is a surgery to move and/or permanently fix a testicle into the scrotum. While orchiopexy typically describes the operation to surgically correct an undescended testicle, it is also used to resolve testicular torsion.
Polyorchidism is the incidence of more than two testicles. It is a very rare congenital disorder, with fewer than 200 cases reported in medical literature and six cases in veterinary literature.
A hydrocele is an accumulation of serous fluid in a body cavity. A hydrocele testis is the accumulation of fluids around a testicle. It is often caused by fluid collecting within a layer wrapped around the testicle, called the tunica vaginalis, which is derived from peritoneum. Provided there is no hernia present, it goes away without treatment in the first year. Although hydroceles usually develop in males, rare instances have been described in females.
A hematocele is a collections of blood in a body cavity or potential space. The term most commonly refers to the collection of blood in the tunica vaginalis around the testes, known as a scrotal hematocele. Hematoceles can also occur in the abdominal cavity and other body cavities. Hematoceles are rare, making them harder to diagnose and treat. They are very common especially as slowly growing masses in the scrotum usually in men older than 50 years.
The male reproductive system consists of a number of sex organs that play a role in the process of human reproduction. These organs are located on the outside of the body and within the pelvis.
Testicular sperm extraction (TESE) is a surgical procedure in which a small portion of tissue is removed from the testicle and any viable sperm cells from that tissue are extracted for use in further procedures, most commonly intracytoplasmic sperm injection (ICSI) as part of in vitro fertilisation (IVF). TESE is often recommended to patients who cannot produce sperm by ejaculation due to azoospermia.
The testicular vein, the male gonadal vein, carries deoxygenated blood from its corresponding testis to the inferior vena cava or one of its tributaries. It is the male equivalent of the ovarian vein, and is the venous counterpart of the testicular artery.
Adenomatoid tumors are rare and benign mesothelial tumors, which arise from the lining of organs. It mainly presents in the genital tract, in regions such as the testis and epididymis. Because of this, researchers had a difficult time concluding that type of tumor has a mesothelial origin. Immunohistochemisty staining of tumor samples show that it is indeed positive for mesothelial-markers. It is the most common extratesticular neoplasm after lipoma, and accounts for 30% of these masses. On the other hand, adenomatoid tumors are the most common tumors of testicular adnexa. Although they are more common to be found in the paratesticular region they are sometimes found in the intratesticular region. It also has been found in other organs such as the pancreas, liver, mesocolon, and adrenal glands. In the female, it has been found in the body of the uterus and the fallopian tube. Most adenomatoid tumors do not cause much pain and can go unnoticed for a long time. Of course, there are a few exceptions to this absence of pain. An example of this is when adenomatoid tumors grow too close to testicular adnexal structures. Tumors of this kind are usually found to be asymptomatic and easily treatable.
The scrotum or scrotal sac is an anatomical male reproductive structure located at the base of the penis that consists of a suspended dual-chambered sac of skin and smooth muscle. It is present in most terrestrial male mammals. The scrotum contains the external spermatic fascia, testes, epididymis, and ductus deferens. It is a distention of the perineum and carries some abdominal tissues into its cavity including the testicular artery, testicular vein, and pampiniform plexus. The perineal raphe is a small, vertical, slightly raised ridge of scrotal skin under which is found the scrotal septum. It appears as a thin longitudinal line that runs front to back over the entire scrotum. In humans and some other mammals the scrotum becomes covered with pubic hair at puberty. The scrotum will usually tighten during penile erection and when exposed to cold temperatures. One testis is typically lower than the other to avoid compression in the event of an impact.
FNA mapping is an application of fine-needle aspiration (FNA) to the testis for the diagnosis of male infertility. FNA cytology has been used to examine pathological human tissue from various organs for over 100 years. As an alternative to open testicular biopsy for the last 40 years, FNA mapping has helped to characterize states of human male infertility due to defective spermatogenesis. Although recognized as a reliable, and informative technique, testis FNA has not been widely used in U.S. to evaluate male infertility. Recently, however, testicular FNA has gained popularity as both a diagnostic and therapeutic tool for the management of clinical male infertility for several reasons:
- The testis is an ideal organ for evaluation by FNA because of its uniform cellularity and easy accessibility.
- The trend toward minimally invasive procedures and cost-containment views FNA favorably compared to surgical testis biopsy.
- The realization that the specific histologic abnormality observed on testis biopsy has no definite correlation to either the etiology of infertility or to the ability to find sperm for assisted reproduction.
- Assisted reproduction has undergone dramatic advances such that testis sperm are routinely used for biological pregnancies, thus fueling the development of novel FNA techniques to both locate and procure sperm.
Orchiectomy is a surgical procedure in which one or both testicles are removed. The surgery is performed as treatment for testicular cancer, as part of surgery for transgender women, as management for advanced prostate cancer, and to remove damaged testes after testicular torsion. Less frequently, orchiectomy may be performed following a trauma, or due to wasting away of the testis or testes.
Scrotalultrasound is a medical ultrasound examination of the scrotum. It is used in the evaluation of testicular pain, and can help identify solid masses.
In biology, a tunica is a layer, coat, sheath, or similar covering. The word came to English from the New Latin of science and medicine. Its literal sense is about the same as that of the word tunic, with which it is cognate. In biology one of its senses used to be the taxonomic name of a genus of plants, but the nomenclature has been revised and those plants are now included in the genus Petrorhagia.
Primary testicular diffuse large B-cell lymphoma (PT-DLBCL), also termed testicular diffuse large B-cell lymphoma and diffuse large B-cell lymphoma of the testes, is a variant of the diffuse large B-cell lymphomas (DLBCL). DLBCL are a large and diverse group of B-cell malignancies with the great majority (-85%) being typed as diffuse large B-cell lymphoma, not otherwise specified. PT-DLBCL is a variant of DLBCL, NOS that involves one or, in uncommon cases, both testicles. Other variants and subtypes of DLBCL may involve the testes by spreading to them from their primary sites of origin in other tissues. PT-DLBCL differs from these other DLBCL in that it begins in the testes and then may spread to other sites.
References
- ↑ Cendron, Marc; Schned, Alan R.; Ellsworth, Pamela I. (1998). "Histological evaluation of the testicular nubbin in the vanishing testis syndrome". The Journal of Urology. 160 (3, part 2): 1161–1163. doi:10.1016/S0022-5347(01)62726-5. PMID 9719300.