Kidneys

The kidneys are vital organs that perform many functions to keep your blood clean and chemically balanced. They are located on either side of your spine, just below your rib cage, and are shaped like beans. ¹²³⁴

Some of the main functions of the kidneys are:

• Filtering about 200 quarts of blood every day to produce about 1 to 2 quarts of urine. The urine contains wastes and extra fluid that are removed from your body. ³⁴
• Regulating the levels of water, salts, and minerals in your blood. The kidneys keep the balance of sodium, potassium, calcium, phosphorus, and other electrolytes that are essential for your body’s functions. ¹²
• Producing hormones that help control your blood pressure, make red blood cells, and keep your bones healthy. The kidneys make renin, which helps regulate blood pressure; erythropoietin, which stimulates the production of red blood cells; and calcitriol, which is the active form of vitamin D that helps maintain calcium balance in the body. ¹²

The kidneys are also involved in other processes, such as removing acid from the blood, synthesizing glucose from amino acids, and excreting some drugs and toxins. ²

The kidneys are composed of millions of tiny filtering units called nephrons. Each nephron consists of a glomerulus, which is a cluster of capillaries that filters the blood, and a tubule, which is a tube that carries the filtered fluid to the bladder. The tubule also reabsorbs some substances from the fluid and secretes others into it. The urine is formed by the combination of the fluid and wastes that are left in the tubule. ¹²

The kidneys receive blood from the renal arteries and return it to the renal veins. The urine flows from the kidneys to the bladder through the ureters, which are muscular tubes that contract to push the urine along. The bladder stores the urine until it is emptied through the urethra, which is a tube that carries urine out of the body. ¹²

The kidneys can be affected by various diseases and conditions that can impair their function or damage their structure. Some examples are:

• Chronic kidney disease (CKD), which is a progressive loss of kidney function over time. CKD can be caused by diabetes, high blood pressure, glomerulonephritis, polycystic kidney disease, and other factors. CKD can lead to kidney failure, which requires dialysis or kidney transplantation to sustain life. ¹
• Acute kidney injury (AKI), which is a sudden decline in kidney function due to trauma, infection, obstruction, or exposure to toxins. AKI can be reversible or irreversible depending on the cause and severity of the damage. AKI can cause complications such as fluid overload, electrolyte imbalance, acidosis, and uremia. ¹
• Nephritic syndrome, which is a group of symptoms caused by inflammation of the glomeruli. Nephritic syndrome can result from infections, autoimmune diseases, or genetic disorders. Nephritic syndrome can cause hematuria (blood in urine), proteinuria (protein in urine), hypertension (high blood pressure), and edema (swelling). ¹
• Nephrotic syndrome, which is a group of symptoms caused by increased permeability of the glomeruli. Nephrotic syndrome can result from diabetes, amyloidosis, lupus, or other causes. Nephrotic syndrome can cause massive proteinuria (protein loss in urine), hypoalbuminemia (low albumin in blood), hyperlipidemia (high cholesterol and triglycerides in blood), and edema (swelling). ¹
• Pyelonephritis, which is a bacterial infection of the kidney and renal pelvis. Pyelonephritis can be caused by urinary tract infections that ascend from the bladder or by blood-borne infections that reach the kidney. Pyelonephritis can cause fever, flank pain, nausea, vomiting, and cloudy or bloody urine. Pyelonephritis can lead to scarring or abscess formation in the kidney if not treated promptly with antibiotics. ¹
• Kidney stones , which are hard deposits of minerals and salts that form in the urinary tract. Kidney stones can be caused by dehydration , diet , infection , or genetic factors . Kidney stones can cause severe pain , hematuria (blood in urine) , infection , or obstruction . Kidney stones can be treated with pain medication , fluids , dietary changes , or procedures to break or remove them .
• Renal cell carcinoma , which is a type of cancer that originates in the kidney . Renal cell carcinoma can be caused by smoking , obesity , hypertension , or genetic factors . Renal cell carcinoma can cause hematuria (blood in urine) , flank pain , weight loss , or metastasis to other organs . Renal cell carcinoma can be treated with surgery , chemotherapy , radiation therapy , or targeted therapy .

The kidneys are essential for your health and well-being. You can protect your kidneys by drinking enough water, eating a balanced diet, avoiding tobacco and alcohol, managing your blood pressure and blood sugar, and getting regular check-ups. If you have any symptoms or risk factors for kidney disease, you should consult your doctor for diagnosis and treatment. ¹.

(1) Your Kidneys & How They Work – NIDDK. https://www.niddk.nih.gov/health-information/kidney-disease/kidneys-how-they-work.
(2) Kidney – Wikipedia. https://en.wikipedia.org/wiki/Kidney.
(3) Kidneys: Location, function, anatomy, pictures, and related diseases. https://www.medicalnewstoday.com/articles/305488.
(4) Kidneys: Location, Anatomy, Function & Health – Cleveland Clinic. https://my.clevelandclinic.org/health/body/21824-kidney.
(5) Getty Images. https://www.gettyimages.com/detail/photo/human-kidneys-medical-illustration-royalty-free-image/1156991077.