Urinary Tract Infections
The urinary tract consists of the organs involved in the production and elimination of liquid waste (urine) from the body: the kidneys, ureters, bladder, and urethra.
There are also two adrenal glands, one on top of each kidney, that produce important hormones the body needs. Men also have a gland called the prostate, located in the pelvis, below the bladder and in front of the rectum. It surrounds the upper part of the urethra and is part of the male reproductive system.
The kidneys are a pair of bean shaped organs in the back of the abdomen. They clean the body of excess water, salt and waste products. As blood circulates through the kidneys, it passes through more than a million tiny filtering units within them. These filtering units produce urine.
Urine flows from the kidneys through a pair of thin tubes, the ureters, to the bladder. (There is one ureter for each kidney.) The bladder, located in the pelvis, is a hollow, muscular, balloon shaped organ that stores urine. Normally, people can hold urine in their bladder until they want to urinate.
During urination, muscles in the wall of the bladder contract, forcing urine out of the bladder and into a tube called the urethra. At the same time, the sphincter muscles that surround the urethra relax. The pelvic floor muscles, below the bladder, assist the sphincter muscles by supporting the bladder and helping it hold or release urine.
One end of the urethra is connected to the bladder; the other end is open. In women, the opening is located just above the vagina. In men, it’s at the tip of the penis. When the bladder muscles tighten and the sphincter muscles relax, urine leaves the body by passing through the opening of the urethra.
Communication between the urinary tract and the brain controls the storage and release of urine. Nerves, running from the bladder and surrounding muscles through the spinal cord to the brain, carry messages between them, telling the brain that the bladder is full. The brain sends messages back to the muscles, telling them either to tighten or release. For the urinary system to work right, the muscles and nerves must work together to hold urine in the bladder and then release it at the right time.