The kidneys are organs located retroperitoneal on both sides of the lumbar spine on the posterior wall of the abdominal cavity. Efficient kidneys are a prerequisite for health. Their impairment can be life-threatening, requiring dialysis or transplantation.

Your kidneys are meticulous guardians of your bloodstream, performing quality control 20 to 25 times a day. They inspect every drop of blood and ensure that its components remain perfectly balanced. Thereby, each kidney gets rid of 1-1.5 litres of urine every day. That’s a lot to pee!

Location and kidney components

Schematic overview of the urinary system

How often is my blood filtered?

Did you know that your kidneys are like the body's own little cleaning machine? Every 24 hours they filter an incredible 120 to 150 litres of blood, carefully filtering out waste and excess fluid to create the masterpiece we call urine. It's like a daily detox routine happening right inside you!

What do kidneys do?

Fluid and Electrolyte Balance (water removal)

The kidneys regulate the balance of fluids and electrolytes (such as sodium, potassium, calcium, and phosphate) in the body. This balance is crucial for maintaining proper cell function and overall health.

Regulation of blood pressure

The kidneys help control blood pressure by regulating the volume of blood in the body and producing hormones like renin that influence blood vessel constriction and fluid retention.

Acid-Base Balance

The kidneys help regulate the body's acid-base balance by controlling the excretion of hydrogen ions and the reabsorption of bicarbonate ions, which help maintain the blood's pH within a narrow range.

Waste Excretion and Filtration

The kidneys eliminate waste products, excess medications, and substances that the body doesn't need, helping to prevent the accumulation of harmful substances in the bloodstream.

Vitamin D Activation/Metabolism

The kidneys play a role in activating vitamin D, which is essential for maintaining healthy bones and aiding in the absorption of calcium from the digestive tract.

Red Blood Cell Production

The kidneys produce a hormone called erythropoietin, which stimulates the bone marrow to produce red blood cells. Red blood cells are essential for carrying oxygen to tissues and removing carbon dioxide.

Why do I need to pee?

Urine is a mix of water, salts, and waste products filtered by the kidneys. As the bladder fills, it stretches, and when it reaches its capacity, it sends a signal to your brain, triggering the urge to pee. This process is your body's way of maintaining a balance, ensuring waste is efficiently eliminated and keeping your internal environment in check.

Interestingly, the urine we excrete has been stored in the bladder for anywhere from 1 to 8 hours.

Drinking water helps to keep your blood vessels open, so that toxins and waste can be easily flushed out. This keeps our bladders flushed, healthy and happy. By drinking smaller amounts throughout the day, we can make sure our body keeps most of that water to keep us hydrated.

Without the renal tubules...

The renal tubules are one of the main parts of a nephron. Nephrons are the filtration unit of the kidneys, you can learn more about their structure here. The tubules help to remove excess acid from the blood. The remaining fluid and wastes in the tubules become urine.The filtered fluid moves along the renal tubules while the blood vessels reabsorb almost all of the water, along with vital minerals and nutrients your body needs such as calcium, magnesium, potassium (kalium) and sodium (natrium).

Calcium is most important for bones structure and helps to maintain muscle and organ function as well as blood clotting. Magnesium supports healthy heart and brain function. Potassium (kalium) supports many functions of the body and can help to reduce kidney stones. Sodium (natrium) helps to keep the fluids in balance and has an important role in keeping nerves and muscles functioning normal.

Without renal tubules, everyday we would lose...