Kidneys are kind of like the Brita filters of the human body. Each of these bean-shaped organs is only about the size of a fist, but they serve several vital functions. In addition to ridding your body of waste, the kidneys also help make red blood cells and regulate your blood pressure. If they aren’t kept healthy, though, they can cause a variety of kidney disease symptoms, from kidney stones to infections that could require a kidney transplant. Here are 11 facts you might not know.
Kidneys are located in the lower back—right below the rib cage—and they’re usually asymmetrical. Your right kidney tends to be smaller and sit a little lower than your left one because it needs to make room for the liver, whose bulkiest part is situated on the right side of your body. Your left kidney, on the other hand, has some more room to sprawl out below the spleen, an organ of smaller stature.
2. There’s a reason why you only need one kidney to live.
Most people have two kidneys at birth, but only one kidney is needed to lead a healthy life. Each kidney has about 1.5 million blood-filtering units called nephrons, which help remove a waste product called urea from blood as it flows through the organs. People only need a minimum of 300,000 nephrons to filter blood properly, and one kidney is more than enough to fulfill this purpose. (People without healthy kidneys can survive with dialysis, a process where blood is filtered by machine, or opt for a kidney transplant.)
Although the heart is responsible for pumping blood throughout the body, the kidneys are doing their fair share of work, too. They filter a half-cup of blood every minute, which works out to be 45 gallons of blood per day—or enough to fill a small bathtub.
4. Kidneys make pee.
As part of the body’s urinary system, kidneys create urine from urea, water, and other waste products. The fluid flows from the kidney’s tubules, which are found inside the nephrons, to two tubes called ureters. The ureters then release the urine into the bladder—and you know what happens from there. But if problems occur, the urine can get backed up and cause kidney infections. In addition, in cases where minerals in the urine crystallize, kidney stones can form.
Prior to 2018, it was commonly thought that ancient Egyptians had no knowledge of the kidneys, even though their understanding of medicine and the human body was advanced in other ways. That changed when an Egyptian papyrus dating back some 3500 years revealed otherwise. It contained the world’s first known description of the kidneys, among other medical insights.
6. Kidneys are mentioned frequently in the Bible.
The kidneys are cited more than 30 times in the Bible—far more frequently than the heart, which was rarely mentioned. According to a 2005 article in the Journal of the American Society of Nephrology by Baylor College of Medicine professor Garabed Eknoyan, it was not uncommon for symbolic meaning to be ascribed to various organs in ancient Middle Eastern texts. “Unlike most ancient literature, however, the kidneys receive special attention in the Bible as the seat of conscience, emotions, desire, and wisdom,” Eknoyan wrote. “The broader region of the loins, which according to the Oxford English Dictionary is implied in the now archaic term ‘reins,’ is considered the site of physical strength and prowess.”
These days, if a patient is unable to pass a kidney stone naturally (albeit painfully), laser and high-frequency sound wave treatments can be used to break the hard mineral deposits into smaller pieces. For much of history, though, a patient’s only option was to go under the knife. Kidney stone surgeries were common from the 16th to 18th centuries, and one of the procedures involved cutting open the perineum, inserting a cutting instrument into the bladder, and chopping up the stone manually. Self-taught surgeon Frère Jacques Beaulieu came up with this technique, but it wasn’t without serious risk. In 1698, 25 of the 60 patients he operated on died.
8. A Dutch doctor used sausage casing, orange juice cans, and a washing machine to invent an "artificial kidney" that predated dialysis.
At the start of World War II, not long after Germany invaded the Netherlands, Dutch doctor Willem Kolff got to work inventing an artificial kidney that evolved into modern-day dialysis. Because supplies were limited during the war, he wrapped semipermeable sausage casings around a wooden drum to create his kidney machine. A patient’s blood was pumped into the casings, and the drum was rotated to remove impurities. Later, he improved his invention by adding orange juice cans and a washing machine to the mix. Some of his earliest patients with kidney failure died after a few days, but in 1945, one woman lived seven more years thanks to Kolff’s machine. When Kolff wasn’t busy creating artificial organs, he was saving lives in other ways: He also established Europe’s first blood blank and helped more than 800 people avoid Nazi concentration camps by hiding them in his hospital.
Staying hydrated helps keep your kidneys in good working order, but on the flip side, you don’t want to drink too much water. Doing so can cause a condition called hyponatremia, which occurs when the sodium in the blood becomes diluted because the kidneys can’t get rid of the fluid fast enough. The condition can be severe, causing swelling of the cells. It's uncommon, though, and it mainly occurs among athletes who overexert their bodies and drink extra water to compensate. So how much water is the right amount? It varies from person to person, but the Health and Medicine Division of the National Academies of Sciences, Engineering, and Medicine suggests that women drink around 9 cups (2.2 liters) per day, and that men drink about 13 cups (3 liters).
10. Too much ibuprofen and aspirin can also harm kidneys.
All drugs pass through your kidneys, so you want to be careful what you’re feeding them. If used daily for long periods of time, pain medications like ibuprofen, higher-dose aspirin, and naproxen (Aleve) can damage kidneys and potentially cause a disease called chronic interstitial nephritis. However, taking a daily low-dose aspirin to prevent heart attacks has no effect on kidney function.
Recent research shows that chronic kidney disease is becoming more prevalent in Central America and parts of Asia, especially among manual laborers who spend most of their day outdoors. Although diabetes and high blood pressure are the main causes of impaired kidney function, these factors were ruled out among workers in El Salvador, Sri Lanka, India, and other countries. Other environmental factors may be involved, but researchers say the extreme heat is largely to blame—and climate change is only making it worse. For one, the more someone sweats, the more dehydrated they become. Over time, this can result in severe kidney damage.
“This can be considered the first disease that’s related to climate change,” Dr. Roberto Lucchini, an environmental medicine and public health professor at Mount Sinai’s Icahn School of Medicine in New York City, tells Mental Floss. He says the problem is so severe in Guatemala that job applicants’ creatinine levels are tested before they’re hired to work an outdoor job. Creatinine is a waste product that gets removed from blood by the kidneys, and if those levels are too high, it could signal a greater risk of kidney disease. Two other studies suggest the problem is even starting to affect outdoor workers in warmer parts of the U.S., including California and Florida. “If this continues as a general trend towards increased temperature, this is concerning,” Lucchini says.
FAQs
What are 5 facts about the kidney? ›
- You Only Need 1 Kidney to Live. While most people have two kidneys, you only need one functioning kidney to lead a healthy life. ...
- Your Kidneys Pump More than 50 Gallons of Blood Daily. ...
- They Regulate Your Body's Salt Content. ...
- Primary Care in Ridgecrest, California.
The average kidney is as big as a cellphone and weighs 4-6 ounces. Even though the kidney only accounts for 0.5% of the body's weight on average, it receives more blood than all other organs except the liver. Nephrons are the filtering units of the kidney, and each kidney has between 1 t0 2 million nephrons.
How much do kidneys weigh? ›A human kidney on average weighs between 120 grams and 150 grams. According to doctors at the hospital, the only two instances of kidneys heavier than this being removed are from the United States (9 kg) and the Netherlands (8.7 kg).
Can you live without kidneys? ›If you have both kidneys completely removed, you will not make any urine. You will need to have kidney dialysis. This is a way of getting rid of waste products and excess water that the kidneys normally filter out of your blood. Dialysis means you can lead a more or less normal life without a working kidney.
Why do we have 2 kidneys? ›They help your bones stay healthy, tell your body when to make new blood cells, and even help you stay upright when you're walking around all day by taking care of your blood pressure. With all those important functions, scientist think having two kidneys must be important for our survival.
What are the 3 main functions of the kidneys? ›- Other Functions of Kidneys.
- Regulate blood pressure.
- Red blood cell regulation.
- Regulating acid balance.
- Sources.
The kidneys are two bean-shaped organs, each about the size of a fist. They are located just below the rib cage, one on each side of your spine. Healthy kidneys filter about a half cup of blood every minute, removing wastes and extra water to make urine.
What is the size of a kidney? ›Normally, kidneys are about the size of a fist or 10 to 12 cm (about 5 inches). Kidney atrophy means that the kidney is smaller than normal.
What are the 9 functions of the kidney? ›- Regulation of extracellular fluid volume. The kidneys work to ensure an adequate quantity of plasma to keep blood flowing to vital organs.
- Regulation of osmolarity. ...
- Regulation of ion concentrations. ...
- Regulation of pH. ...
- Excretion of wastes and toxins. ...
- Production of hormones.
- maintaining overall fluid balance.
- regulating and filtering minerals from blood.
- filtering waste materials from food, medications, and toxic substances.
- creating hormones that help produce red blood cells, promote bone health, and regulate blood pressure.
What are 3 diseases that affect the kidney? ›
- Atypical hemolytic uremic syndrome (aHUS)
- Alport syndrome.
- Amyloidosis.
- Cystinosis.
- Fabry disease.
- Focal segmental glomerulosclerosis (FSGS)
- Glomerulonephritis (glomerular disease)
- Goodpasture syndrome.
Most people have two kidneys, which are organs shaped like kidney beans, each one about 10-15cms long, located either side of the spine, deep in the abdomen. However, it is possible to live a healthy and active life with only one functioning kidney.
Can you have pain in kidney? ›Kidney pain — also called renal pain — refers to pain from disease or injury to a kidney. You might feel kidney pain or discomfort as a dull, one-sided ache in your upper abdomen, side or back. But pain in these areas is often unrelated to your kidneys.
Which side of kidney is bigger? ›The left kidney is usually a little larger than the right. The left kidney is usually also positioned slightly higher and closer to the heart than the right. One or both kidneys can atrophy, but it may be more likely to occur to the left kidney.
What is the heaviest body organ? ›The largest solid internal organ is your liver. It weighs approximately 3–3.5 pounds or 1.36–1.59 kilograms and is about the size of a football.
How does a kidney work? ›Here's how kidneys perform their important work:
Blood enters the kidneys through an artery from the heart. Blood is cleaned by passing through millions of tiny blood filters. Waste material passes through the ureter and is stored in the bladder as urine. Newly cleaned blood returns to the bloodstream by way of veins.
Most people live normal, healthy lives with one kidney. However, it's important to stay as healthy as possible, and protect the only kidney you have.
Why do kidneys fail? ›What causes kidney failure? High blood pressure and diabetes are the two most common causes of kidney failure. They can also become damaged from physical injury, diseases, or other disorders.
How long can you live with 1 kidney? ›Most people with a single kidney live a normal life without developing any long- or short-term problems. However, the risk of developing mild high blood pressure, fluid retention, and proteinuria is slightly higher if you have one kidney instead of two.
Can you have 3 kidneys? ›Three kidneys are relatively uncommon. It usually is only discovered by accident as it rarely causes symptoms. It usually means that one of the kidneys were split into two prior to birth. It can be associated with infections and kidney stones, but usually causes no symptoms at all.
Are kidneys the same size? ›
The kidneys are just naturally unequal in size. The right kidney is commonly slightly bigger than the left, but some people are born with a larger left kidney than right. The kidneys are generally close to each other in size with the size difference generally less than one centimeter in length.
Is sugar good for kidney? ›Sugar is not a problem for the kidneys unless the blood sugar level gets too high. This commonly occurs in both Type 1 and Type 2 diabetes. Once the blood sugar level gets higher than 180 mg/dl, the kidneys start to spill sugar into the urine. The higher the blood sugar, the more sugar comes out in the urine.
What do kidneys produce? ›The kidneys make two main hormones, vitamin D and erythropoietin. Vitamin D is essential for a number of different functions in the body. Most of the vitamin D that is in the blood is inactive and it is modified by the kidney and other tissues to activate it.
What organ helps pee? ›Bladder. This triangle-shaped, hollow organ is located in the lower abdomen. It is held in place by ligaments that are attached to other organs and the pelvic bones. The bladder's walls relax and expand to store urine, and contract and flatten to empty urine through the urethra.
What is urine made of? ›It consists of water, urea (from amino acid metabolism), inorganic salts, creatinine, ammonia, and pigmented products of blood breakdown, one of which (urochrome) gives urine its typically yellowish colour.
What waste does the kidney remove? ›The kidneys remove waste products called urea from the blood through tiny filtering units called nephrons. There are about one million nephrons in each kidney.
What color is urine when your kidneys are failing? ›When kidneys are failing, the increased concentration and accumulation of substances in urine lead to a darker color which may be brown, red or purple. The color change is due to abnormal protein or sugar, high levels of red and white blood cells, and high numbers of tube-shaped particles called cellular casts.
How do I keep my kidneys healthy? ›- Make healthy food choices. ...
- Make physical activity part of your routine. ...
- Aim for a healthy weight. ...
- Get enough sleep. ...
- Stop smoking. ...
- Limit alcohol intake link. ...
- Explore stress-reducing activities. ...
- Manage diabetes, high blood pressure, and heart disease.
The kidneys are two bean-shaped organs, each about the size of a fist. They are located just below the rib cage, one on each side of your spine. Healthy kidneys filter about a half cup of blood every minute, removing wastes and extra water to make urine.
How many kidneys do we have? ›Most people have two kidneys, which are organs shaped like kidney beans, each one about 10-15cms long, located either side of the spine, deep in the abdomen. However, it is possible to live a healthy and active life with only one functioning kidney.
What are 3 diseases that affect the kidney? ›
- Atypical hemolytic uremic syndrome (aHUS)
- Alport syndrome.
- Amyloidosis.
- Cystinosis.
- Fabry disease.
- Focal segmental glomerulosclerosis (FSGS)
- Glomerulonephritis (glomerular disease)
- Goodpasture syndrome.
- Remove waste products and medicines from the body.
- Balance the body's fluids.
- Balance a variety of electrolytes.
- Release hormones to control blood pressure.
- Release a hormone to control red blood cell production.
- Help with bone health by controlling calcium and phosphorus.
Your bladder is connected to your kidneys by two ureters. It is a hollow organ designed to store urine. It can hold between one and one-half and two cups of urine or around 400 ml to almost 500 ml. The inside of the bladder is lined with a layer of transitional epithelial cells.
Where is urine stored? ›Urine moves from the kidneys through narrow tubes to the bladder. These tubes are called the ureters. The bladder stores urine until it's time to urinate. Urine leaves the body through another small tube called the urethra.
What is the size of a kidney? ›Normally, kidneys are about the size of a fist or 10 to 12 cm (about 5 inches). Kidney atrophy means that the kidney is smaller than normal.
Why do we have 2 kidneys? ›They help your bones stay healthy, tell your body when to make new blood cells, and even help you stay upright when you're walking around all day by taking care of your blood pressure. With all those important functions, scientist think having two kidneys must be important for our survival.
What causes kidney failure? ›What causes kidney failure? High blood pressure and diabetes are the two most common causes of kidney failure. They can also become damaged from physical injury, diseases, or other disorders.
Are kidneys the same size? ›The kidneys are just naturally unequal in size. The right kidney is commonly slightly bigger than the left, but some people are born with a larger left kidney than right. The kidneys are generally close to each other in size with the size difference generally less than one centimeter in length.
Can one kidney fail? ›Kidney failure (renal failure) means one or both of your kidneys no longer function well on their own. Kidney failure is sometimes temporary and develops quickly (acute). Other times it's a chronic (long-term) condition that slowly gets worse. Kidney failure is the most severe stage of kidney disease.
Can you have 3 kidneys? ›Three kidneys are relatively uncommon. It usually is only discovered by accident as it rarely causes symptoms. It usually means that one of the kidneys were split into two prior to birth. It can be associated with infections and kidney stones, but usually causes no symptoms at all.
What are the 5 types of kidney failure? ›
- Acute prerenal kidney failure. Insufficient blood flow to the kidneys can cause acute prerenal kidney failure. ...
- Acute intrinsic kidney failure. ...
- Chronic prerenal kidney failure. ...
- Chronic intrinsic kidney failure. ...
- Chronic post-renal kidney failure.
Most humans are born with two kidneys as the functional components of what is called the renal system, which also includes two ureters, a bladder and a urethra. The kidneys have many functions, including regulating blood pressure, producing red blood cells, activating vitamin D and producing some glucose.
Can kidneys heal? ›Often, treatment for acute kidney failure, especially if severe, requires hospitalization. If there aren't any other problems, the kidneys may heal themselves. In most other cases, acute kidney failure can be treated if it's caught early.