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Testosterone

A hormone made mainly in the testes (part of the male reproductive system). It is needed to develop and maintain male sex characteristics, such as facial hair, deep voice, and muscle growth. Testosterone may also be made in the laboratory and is used to treat certain medical conditions.

PubMed Health Glossary
(Source: NIH - National Cancer Institute)

Anatomy of the male reproductive and urinary systems; drawing shows front and side views of ureters, lymph nodes, rectum, bladder, prostate gland, vas deferens, penis, testicles, urethra, seminal vesicle, and ejaculatory duct. Click to enlarge

Parts of the male reproductive and urinary systems National Institutes of Health

Terms to know

Bladder
The organ that stores urine.
Ejaculatory Ducts
Either of a pair of ducts through which semen passes, each of which is formed by the merging of the vas deferens and the duct of the seminal vesicle.
Glands
A group of cells that secrete substances. Endocrine glands secrete hormones. Exocrine glands secrete salt, enzymes, and water.
Hormones
A messenger molecule that helps coordinate the actions of various tissues; made in one part of the body and transported, via the bloodstream, to tissues and organs elsewhere in the body.
Lymph Nodes
A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Lymph nodes filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells). They are located along lymphatic vessels. Also called lymph gland.
Penis
An external male reproductive organ. It contains a tube called the urethra, which carries semen and urine to the outside of the body.
Prostate
A gland in the male reproductive system. The prostate surrounds the part of the urethra (the tube that empties the bladder) just below the bladder, and produces a fluid that forms part of the semen.
Rectum
The last several inches of the large intestine closest to the anus.
Scrotum
In males, the external sac that contains the testicles.
Semen
The fluid that is released through the penis during orgasm. Semen is made up of sperm from the testicles and fluid from the prostate and other sex glands.
Seminal Vesicle
A gland that helps produce semen.
Sperm
The male reproductive cell, formed in the testicle. A sperm unites with an egg to form an embryo.
Testicles (Testes)
One of two egg-shaped glands inside the scrotum that produce sperm and male hormones. Also called testicle.
Ureter
The tube that carries urine from the kidney to the bladder.
Urethra
The tube that carries urine from the bladder to the outside of the body.
Vas Deferens
A coiled tube that carries the sperm out of the testes.

Related conditions

Terms to know

Bladder
The organ that stores urine....
Ejaculatory Ducts
Either of a pair of ducts through which semen passes, each of which is formed by the merging of the vas defer...
Glands
A group of cells that secrete substances. Endocrine glands secrete hormones. Exocrine glands secrete salt,...
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