The kidneys are two bean-shaped organs that extract waste from blood,
balance body fluids, form urine, and aid in other important functions of the
They reside against the back muscles in the upper abdominal cavity. They sit
opposite each other on either side of the spine. The right kidney sits a little
bit lower than the left to accommodate the liver.
When it comes to components of the urinary system, the kidneys are multi-functional
powerhouses of activity. Some of the core actions of the kidneys include:
- Waste excretion:
There are many things your body doesn’t want inside of it. The kidneys
filter out toxins, excess salts, and urea,
a nitrogen-based waste created by cell metabolism. Urea is synthesized in
the liver and transported through the blood to the kidneys for removal.
- Water level balancing:
As the kidneys are key in the chemical breakdown of urine, they react to
changes in the body’s water level throughout the day. As water intake
decreases, the kidneys adjust accordingly and leave water in the body
instead of helping excrete it.
- Blood pressure
regulation: The kidneys need constant pressure to filter the
blood. When it drops too low, the kidneys increase the pressure. One way is
by producing a blood vessel-constricting protein (angiotensin) that also signals the body to retain sodium and
water. Both the constriction and retention help restore normal blood
- Red blood cell
regulation: When the kidneys don’t get enough oxygen, they send
out a distress call in the form of erythropoietin,
a hormone that stimulates the bone marrow to produce more oxygen-carrying
red blood cells.
- Acid regulation:
As cells metabolize, they produce acids. Foods we eat can either increase
the acid in our body or neutralize it. If the body is to function
properly, it needs to keep a healthy balance of these chemicals. The
kidneys do that, too.
Most people are born with two kidneys, but many people can live on just one.
Kidney transplant surgeries with live donors are common medical procedures
Because of all of the vital functions the kidneys perform and the toxins
they encounter, the kidneys are susceptible to various problems.
Acute kidney failure is a condition in which the kidneys
suddenly lose their ability to function properly. This can occur for many
- Blood-clotting disorders
- Decreased blood flow caused
by low blood pressure
- Autoimmune kidney disorders
- Urinary tract infections
- Complications from pregnancy