The Urinary System (Renal System)
The urinary tract is the body’s filtering system for removing wastes and extra water and regulates chemicals in the blood called electrolytes.
The kidneys filter the blood and returns the chemicals and other substances such as sugar, other nutrients and minerals that the body needs to the blood. The excess substances are excreted in the urine. Examples of electrolyes are sodium, calcium, and potassium.
The urinary tract includes two kidneys, two ureters, a bladder, and a urethra.
The kidneys are a pair of bean-shaped organs, each about the size of a fist.
They are located below the ribs, under the diaphragm, one on each side of the spine, toward the middle of the back.
Every minute, a person’s kidneys filter about 3 ounces of blood, removing wastes and extra water. The wastes and extra water make up the 1 to 2 quarts of urine an adult produces each day.
Children produce less urine each day; the amount produced depends on their age.
The urine travels from the kidneys down two narrow tubes called the ureters.
The urine is then stored in a hollow muscular organ called the bladder.
When the bladder empties, urine flows out of the body through a tube called the urethra at the bottom of the bladder.
The opening of the urethra is called the urinary meatus.
The prostate gland surrounds the urethra just below the urinary bladder. The prostate secretes the milky fluid component of the semen. This is expelled through the urethra during ejaculation. The prostate gland is not a part of the urinary system but can affect urination when it is enlarged or inflamed.
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