Kidneys

 Kidneys

The kidneys are two bean-shaped organs that are part of the urinary system. They are located on either side of the spine, just below the rib cage, with the right kidney sitting slightly lower than the left because of the liver. Each kidney is about the size of a fist and is essential for maintaining the body's internal balance.

Functions of the kidneys

The kidneys perform several vital functions:

Filter blood: Remove waste products and excess water from the blood.

Produce urine: Waste and extra fluid are excreted as urine.

Maintain fluid balance: Keep the right amount of water in the body.

Regulate electrolytes: Control levels of sodium, potassium, calcium, and phosphate.

Maintain acid-base balance: Keep the blood at a healthy pH.

Control blood pressure: Produce the hormone renin, which helps regulate blood pressure.

Produce red blood cells: Release erythropoietin (EPO), which stimulates bone marrow to make red blood cells.

Activate vitamin D: Convert vitamin D into its active form to help absorb calcium and maintain healthy bones.

Structure of the kidney

Each kidney consists of:

Renal cortex: The outer layer where blood filtration begins.

Renal medulla: The inner region containing pyramid-shaped structures that concentrate urine.

Renal pelvis: A funnel-shaped area that collects urine before it passes into the ureter.

Nephrons: About 1 million nephrons are present in each kidney. These are the functional units responsible for filtering blood and producing urine.

How the kidneys work

1. Blood enters the kidneys through the renal arteries.

2. Nephrons filter the blood, removing waste products and excess water.

3. Useful substances such as glucose, amino acids, and much of the water are reabsorbed into the bloodstream.

4. The remaining waste becomes urine.

5. Urine flows through the ureters to the bladder, where it is stored before being excreted through the urethra.

Common kidney diseases

Chronic kidney disease (CKD): Gradual loss of kidney function over time.

Acute kidney injury (AKI): Sudden decline in kidney function.

Kidney stones: Hard deposits of minerals that form inside the kidneys.

Urinary tract infections (UTIs): Infections that can spread to the kidneys if untreated.

Polycystic kidney disease: An inherited disorder in which cysts develop in the kidneys.

Glomerulonephritis: Inflammation of the kidney's filtering units.

Symptoms of kidney disease

Early kidney disease may cause few or no symptoms. As it progresses, symptoms can include:

Swelling of the feet, ankles, or face

Fatigue and weakness

Reduced or increased urination

Blood in the urine

Foamy urine

Persistent nausea or vomiting

High blood pressure

Loss of appetite

Itchy skin

Difficulty concentrating

Risk factors

Diabetes

High blood pressure

Obesity

Smoking

Family history of kidney disease

Older age

Long-term use of some painkillers (NSAIDs)

Keeping your kidneys healthy

Drink enough water.

Maintain healthy blood pressure and blood sugar.

Eat a balanced diet low in excessive salt.

Exercise regularly.

Avoid smoking and limit alcohol.

Use painkillers only as directed.

Have regular health check-ups if you have diabetes or hypertension.

Interesting facts

The kidneys filter about 180 liters of fluid each day, but only about 1–2 liters become urine.

A healthy person can usually live a normal life with one functioning kidney.

The kidneys receive about 20–25% of the heart's blood output, highlighting how important they are in filtering the blood.

Conclusion

The kidneys are vital organs that filter waste, regulate body fluids, control blood pressure, produce hormones, and help maintain healthy bones and red blood cell production. Protecting kidney health through a healthy lifestyle and managing conditions such as diabetes and hypertension can help prevent kidney disease and support overall well-being.