The testicles. What the testicles do. Germ cells. Stromal cells. References American Cancer Society. What Is Testicular Cancer? Cancer Research UK. About Testicular Cancer. Human Anatomy. San Francisco: Pearson Benjamin Cummings; National Cancer Institute.
Reuter, VE. It also stimulates the production of sperm. Alongside the testicles are the epididymis and the vas deferens, which transport sperm. The epididymis pronounced: ep-uh-DID-uh-miss and the testicles hang in a pouch-like structure outside the pelvis called the scrotum. This bag of skin helps to regulate the temperature of testicles, which need to be kept cooler than body temperature to produce sperm. The scrotum changes size to maintain the right temperature.
When the body is cold, the scrotum shrinks and becomes tighter to hold in body heat. When it's warm, it gets larger and floppier to get rid of extra heat. This happens without a guy ever having to think about it. The brain and the nervous system give the scrotum the cue to change size. The accessory glands , including the seminal vesicles and the prostate gland , provide fluids that lubricate the duct system and nourish the sperm. The urethra pronounced: yoo-REE-thruh is the channel that carries the sperm in fluid called semen to the outside of the body through the penis.
The urethra is also part of the urinary system because it is also the channel through which pee passes as it leaves the bladder and exits the body. The penis is actually made up of two parts: the shaft and the glans. The shaft is the main part of the penis and the glans is the tip sometimes called the head.
At the end of the glans is a small slit or opening, which is where semen and pee exit the body through the urethra. The inside of the penis is made of a spongy tissue that can expand and contract. All boys are born with a foreskin , a fold of skin at the end of the penis covering the glans.
Some boys are circumcised, which means that a doctor or clergy member cuts away the foreskin. Circumcision is usually done during a baby boy's first few days of life.
It's not medically necessary, but parents who choose to have their sons circumcised often do so based on religious beliefs, concerns about hygiene, or cultural or social reasons. Guys who have circumcised penises and those who don't are no different: All penises work and feel the same, regardless of whether the foreskin has been removed.
When a baby boy is born, he has all the parts of his reproductive system in place, but it isn't until puberty that he is able to reproduce. When puberty begins, usually between the ages of 9 and 15, the pituitary gland — located near the brain — secretes hormones that stimulate the testicles to produce testosterone.
The production of testosterone brings about many physical changes. Although the timing of these changes is different for every guy, the stages of puberty generally follow a set sequence:. They form in the abdomen, and drop into the scrotum during their seventh month of gestation.
Sometimes, though, the testicles do not drop, and the baby is born with a condition called undescended testicles. This happens for about 2 percent of males, and in 10 percent of those cases, both testicles are not in their proper position, according to the Mayo Clinic.
Typically, this is a problem associated with preemies and the testicles often "drop" within a few months. If not, surgery may be required. Once testicles have dropped, they may not stay there. Retractile testicle is when a testicle moves into the groin area. Usually, a doctor can move the testicle back into its proper position, but if it is stuck, it is called an ascending testicle or an acquired undescended testicle.
In this case, surgery may be needed to move it into proper position and stitch it into place. A more serious condition of this organ is testicular cancer. It usually occurs in men 15 and 34 years old.
In , around 8, new cases of testicular cancer will be diagnosed and deaths will be attributed to testicular cancer in the United States, according to the American Cancer Society. Though these numbers seem large, only around about 1 in males get this type of cancer. Testicular cancer can be caused when the germline stem cells don't turn into sperm cells after a long period of time, according to National Geographic.
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