The urinary system

The urinary system consists of the kidneys, ureters, urinary bladder, and urethra. The kidneys filter the blood to remove wastes and produce urine. The ureters, urinary bladder, and urethra together form the urinary tract, which acts as a plumbing system to drain urine from the kidneys, store it, and then release it during urination. Besides filtering and eliminating wastes from the body, the urinary system also maintains the homeostasis of water, ions, pH, blood pressure, calcium and red blood cells.

The vulva

The vulva

The vulva is the collective name for the external female genitalia in the pubic region, including the labia, clitoris, and urethral and vaginal openings. These organs work together to support urination and sexual reproduction.

The exterior of the vulva begins as a mound of skin-covered adipose known as the mons pubis that arises from the skin covering the pubis bone in the pubic region. As it continues inferiorly, the mons pubis divides laterally into the two parallel labia majora. The labia majora are wide folds of skin and adipose that rise beyond the mons pubis and surround the pudendal cleft, a deep vertical furrow in the center of the vulva. Both the mons pubis and labia majora are covered in pubic hair following puberty and serve to protect the delicate structures of the vulva found in the pudendal cleft.

The vagina

The vagina is an elastic, muscular tube connecting the cervix of the uterus to the vulva and exterior of the body. The vagina is located in the pelvic body cavity posterior to the urinary bladder and anterior to the rectum. Measuring around 3 inches in length and less than an inch in diameter, the vagina stretches to become several inches longer and many inches wider during sexual intercourse and childbirth. The inner surface of the vagina is folded to provide greater elasticity and to increase friction during sexual intercourse.

The urinary bladder

The urinary bladder is a hollow elastic organ that functions as the body’s urine storage tank. Urine produced by the kidneys flows through the ureters to the urinary bladder, where is it stored before passing into the urethra and exiting the body. The urinary bladder plays an important role in delaying and controlling urination so that the average person only has to urinate several times each day instead of constantly leaking small amounts of urine.

The urethra

The urethra is a tube that conveys urine from the urinary bladder to the outside of the body. Its wall is lined with mucous membranes and contains a relatively thick layer of smooth muscle tissue. It also contains numerous mucous glands, called urethral glands that secrete mucus into the urethral canal.

The prostate

Found only in men, the prostate is a walnut-sized gland that grows throughout a man’s life and may eventually interfere with or prevent urination by blocking the urethra. The prostate makes a significant contribution to the production and ejaculation of semen during sexual intercourse. Prostate cancer is a common disorder of the prostate that often necessitates the surgical removal of the prostate.

The penis

The penis is the male external excretory and sex organ. The penis contains the external opening of the urethra, which is used for urination and to deliver semen into the vagina of a female sexual partner. Erectile tissue inside the penis allows the penis to increase in size and become rigid during sexual stimulation. A penis' erection helps to deliver semen deeper into the female reproductive tract during sexual intercourse.

The kidneys

The kidneys are the waste filtering and disposal system of the body. As much as 1/3 of all blood leaving the heart passes into the kidneys to be filtered before flowing to the rest of the body’s tissues. While a person could live with only one functioning kidney, our kidneys are vital organs; the loss of both kidneys would lead to a rapid accumulation of wastes and death within a few days time.

The urinary system of the lower torso

Excess ions and metabolic wastes produced by the body’s cells must be constantly removed from the body to prevent toxic substances from accumulating and poisoning the body. The urinary system of the lower abdomen contains all of the major organs that filter wastes from the blood stream and remove the wastes from the body as urine. These organs include the kidneys, ureters, urinary bladder, and urethra.