Understanding how kidneys work

The kidneys are powerful organs that play a vital role in keeping the human body healthy. What’s more, they perform not just one but three essential functions in our bodies.

First, they regulate the amount of water in our systems. Our bodies need just the right amount of water to work properly and the kidneys remove excess water that we don’t need or retain the water that we do need.

They eliminate wastes and toxins. For our bodies to function properly, we need to maintain the right mix of minerals and other substances in our blood and fluids. The kidneys help eliminate excess amounts of minerals such as sodium, potassium and phosphorus, as well as wastes such as urea (a result of protein breaking down) and acids.

The phenomenal work of the kidneys doesn’t stop there. They also produce hormones that help regulate blood pressure, produce red blood cells, and control the calcium balance in our bodies.

Kidneys are two small organs located just below the ribcage on either side of the spine. The two kidneys filter about 120 litres of blood a day, producing 1 to 2 litres of urine, which is made up of wastes and extra fluid.

A small tube called the ureter extends from each kidney down to the bladder; the ureters carry urine to the bladder, where it is held until the person is ready to eliminate it.

Each kidney is made up of about a million nephrons, which do the blood filtering work to rid the body of wastes and toxins. The nephrons send minerals the body needs back into the bloodstream and eliminate the wastes the body does not need. 

When kidneys don’t function properly

When kidneys don’t function properly

Kidney disease is a term that encompasses a variety of diseases and disorders, and it’s the result of the kidneys slowing down or failing to work. A person can suffer from acute kidney disease, which develops suddenly and lasts a short time. Some acute diseases can result in serious, long-lasting consequences but others may be resolved once the underlying cause is found and treated.

Chronic kidney disease is a different grouping of diseases; these conditions do not go away with treatment and usually get worse over time. There is no single cause of chronic kidney disease. Some kidney diseases are present when the child is born (inherited) while others develop as the child grows up (acquired). Chronic disease eventually leads to endstage kidney disease, also known as ESRD, which requires dialysis or a kidney transplantation. 

Montreal Children's Hospital
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