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what do the
kidneys do?
Home » Patients » Understand CKD » The kidneys play a crucial role in the human body by filtering waste and excess water from the blood, regulating blood pressure, and maintaining electrolyte balance.
WHAT DO THEY LOOK LIKE?
The kidneys are two bean-shaped organs located on either side of the spine in the lower abdomen. They measure approximately 10 to 12 centimeters in length, 5 to 7 centimeters in width, and 3 to 4 centimeters in thickness.19
Each kidney is composed of several layers:
- Cortex : the outer layer, where the nephrons, the functional units of the kidneys, are located.
- The renal medulla : The inner layer, composed of structures called renal pyramids.
- The calyces : A cup-shaped structure that collects urine from the renal pyramids.
- The renal pelvis : A larger cavity where urine from the calyces is collected before passing into the ureters.
The kidneys are also surrounded by a fibrous capsule and adipose tissue that protect them.
WHAT IS THEIR MAIN FUNCTIONS ?
Your kidneys play a vital role in eliminating waste and toxins produced by your body after each meal or physical effort. They continuously filter your blood through millions of nephrons, transforming excess fluids and waste into urine. The urine is then transported to your bladder before being naturally expelled.19
In addition, they perform several essential functions for the body:
Water and electrolyte balance: They regulate the amount of water and mineral salts (sodium, potassium) in the body.
Hormone production: :
- They secrete hormones (renin-angiotensin system) that regulate blood pressure by controlling blood volume.
- They contribute to the production of erythropoietin (EPO), which stimulates red blood cell production, and activate vitamin D, which is essential for bone tissue quality.
Calcium and phosphorus metabolism: They regulate the reabsorption and excretion of these two molecules. An increase in phosphorus can lead to a decrease in calcium, and vice versa. The kidneys help maintain this delicate balance.
A diseased kidney is no longer able to fully perform these functions, leading to numerous health consequences.
