Genitourinary Overview

Conditions considered in this diagnostic category include pathological entities pertaining to the renal and urologic tract which are common to both sexes, and conditions affecting only the male reproductive system. Conditions of the female reproductive system are included under the separate diagnostic category entitled, Gynecological Conditions and Disorders of the Breast.

Important functions of the kidney and urinary system are to remove excess fluid and waste materials, and to retain substances ultimately related to regulating acid-base balance, fluid and electrolyte balance, and, indirectly, all body fluids. The system includes: two organs shaped like beans, with each one positioned at the back of the cavity of the abdomen on each side of the spinal column (kidneys); two muscular tubes, each originating in a kidney, that serve as ducts to carry urine from each kidney to the bladder (ureter); a muscular reservoir located in the anterior portion of the lower pelvis cavity that stores urine (the bladder); and a tube for discharge of urine that extends from the bladder to the outside (urethra). In females, the urethral opening (meatus) lies between the vagina and the clitoris (anterior to the vaginal opening). In males, the urethra passes through the prostate gland and penis, with the opening (meatus) at the end of the penis. In males, semen and urine use the urethra as a passageway.

The principal organs of the urinary system are the kidneys. The basic structural units of the kidneys are the nephrons which carry out the two main functions of the urinary system; mechanical filtration of fluid and selective reabsorption and secretion of ions. The nephron consists of glomeruli (tufts of small blood vessels) surrounded by Bowman's capsule, a tubular apparatus, and a collecting duct. Blood enters the kidney through the renal artery and then passes through the nephrons. The collecting tubules unite to form ducts that empty urine into extensions of the pelvis of the kidney (calyces). Following entrance into the ureters, the urine is transported to the bladder. Normal functioning involves voluntary control of expulsion of urine from the bladder through the urethra, stimulated by neural effects on the bladder.

There is an overlap particularly involving the urinary and reproductive systems of men. The organs of the male reproductive system consist of external and internal structures. External structures include the penis and the scrotum, and internal structures include the prostate gland, the seminal vesicles, and several ducts. The penis, composed of erectile tissue and skin, is the male sexual organ. The scrotum, a pouch-like structure consisting of two halves, contains the testicles and part of the spermatic cord. Sperm cells are produced in the testicles, and the male hormone (testosterone) is secreted by the testicles. The prostate gland surrounds the neck of the bladder and the urethra, and has openings into the urethra. The gland secretes a fluid that forms a part of the discharge of semen. The seminal vesicles lie behind the bladder close to the prostate gland and secrete a fluid that forms a part of the semen. The seminal ducts function to convey sperm.