Most of the male reproductive system – the penis, scrotum, and testes – is outside the abdomen. Consequently, symptoms of disorders in these structures are usually obvious at an early stage. Such symptoms should not be ignored out of embarrassment since most genital disorders can be cured by prompt treatment.
In this section, disorders that affect the epididymis (the coiled tube that carries sperm away from each testis) and the testes are described first. These disorders range from epididymal cysts, which are harmless collections of fluid, to cancer of the testis.
The next articles discuss disorders of the scrotum, the sac in which the testes are suspended. These disorders are usually not serious and include varicose veins in the scrotum, known as varicocele, and hydrocele, in which fluid collects around the testis.
Disorders caused by inflammation of the penis and foreskin are covered next, followed by two disorders of erectile function of the penis. The final article in this section discusses cancer of the penis, a very rare but distressing disorder that, if diagnosed early, responds well to treatment.
Skin conditions that may affect the penis and scrotum are discussed elsewhere (see Skin, hair, and nails), as are male hormonal disorders including abnormal puberty, sexual problems such as erectile dysfunction, infertility, and sexually transmitted infections. Conditions that develop in the male genitals during childhood are covered in disorders of the urinary and reproductive systems (see Infancy and childhood).
For further information on the structure and function of the testes, scrotum, and penis, see Sex and Reproduction.
The prostate gland is a firm, round organ about the size of a chestnut. It surrounds the upper part of the urethra (the tube through which urine is emptied from the bladder) and lies underneath the bladder and directly in front of the rectum. The secretions that are produced by the prostate gland are added to semen, the fluid that contains sperm.
Disorders affecting the prostate gland are very common, particularly in men over the age of 30. Prostatitis, in which the prostate gland is inflamed, is the first disorder discussed in this section. Enlargement of the prostate gland is covered next. Some degree of prostate enlargement occurs in most men over the age of 50 and is often viewed as a natural part of aging. The final article covers prostate cancer. In many cases, prostate cancer is not life-threatening, and in older men it may not require treatment because the tumour is often slow-growing and may not affect life expectancy. However, prostate cancer in younger men may spread to other parts of the body more quickly and can be life-threatening. Current research is therefore aimed at developing tests to detect prostate cancer before symptoms start to appear. However, although these tests can help to identify prostate cancer in its early stages, they cannot identify which cancers are more likely to spread and require early treatment.
For further information on the structure and function of the male reproductive system, see Male Reproductive System.
The most important male sex hormone is testosterone, which influences sperm production, fertility, and sex drive. Male sex hormones also promote the development of secondary sexual characteristics at puberty. Over- or underproduction of male sex hormones may be due to a variety of factors, including inherited disorders, long-term illnesses, tumours, or lifestyle factors.
Male sex hormones, or androgens, are produced mainly by the testes but also by the adrenal glands. The production of male sex hormones is controlled by hormones secreted by the pituitary gland. In turn, the pituitary gland is under the control of a part of the brain called the hypothalamus.
The changes that occur at puberty are controlled by the sex hormones. This section starts by discussing early or late onset of puberty in boys, which may be a symptom of under- or overproduction of male sex hormones. Hypogonadism, in which male sex hormones are underproduced, is covered next. In boys, this condition can suppress sexual development; in men, hypogonadism lowers sperm production and fertility. The final article discusses gynaecomastia, breast enlargement in males that temporarily affects nearly half of all boys during puberty.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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