Anatomy and Function of the Urinary System
How does the urinary system work?
The body takes nutrients from food and converts them to energy.
After the body has taken the food that it needs, waste products
are left behind in the bowel and in the blood.
The urinary system keeps the chemicals and water in balance by
removing a type of waste called urea from the blood. Urea is produced
when protein, found in meat products, are broken down in the body.
Urinary system parts and their functions:
- two kidneys - a pair of purplish-brown organs located
below the ribs toward the middle of the back. Their function
is to:
- remove liquid waste from the blood in the form of urine.
- keep a stable balance of salts and other substances in
the blood.
- produce erythropoietin, a hormone that aids the formation
of red blood cells.
The kidneys remove urea from the blood through tiny filtering
units called nephrons. Each nephron consists of a ball formed
of small blood capillaries, called a glomerulus, and a small
tube called a renal tubule. Urea, together with water and
other waste substances, forms the urine as it passes through
the nephrons and down the renal tubules of the kidney.
- two ureters - narrow tubes that carry urine from the
kidneys to the bladder. Muscles in the ureter walls continually
tighten and relax forcing urine downward, away from the kidneys.
If urine backs up, or is allowed to stand still, a kidney infection
can develop. About every 10 to 15 seconds, small amounts of
urine are emptied into the bladder from the ureters.
- bladder - a triangle-shaped, hollow organ located in
the lower abdomen. It is held in place by ligaments that are
attached to other organs and the pelvic bones. The bladder's
walls relax and expand to store urine, and contract and flatten
to empty urine through the urethra.
- two sphincter muscles - circular muscles that help
keep urine from leaking by closing tightly like a rubber band
around the opening of the bladder.
- nerves in the bladder -alert a person when it is time
to urinate, or empty the bladder.
- urethra -the tube that allows urine to pass outside
the body. The brain signals the bladder muscles to tighten,
which squeezes urine out of the bladder. At the same time, the
brain signals the sphincter muscles to relax to let urine exit
the bladder through the urethra. When all the signals occur
in the correct order, normal urination occurs.
Click here to view the
Online Resources page of this Web. |
CarePages is free and easy to use. It allows you
to build a virtual meeting place, share news and photos online while a
loved one is receiving medical care. |
|
