The kidneys are a pair of bean-shaped organs on either side of your spine, below your ribs and behind your belly. They help the body pass waste as urine. They also help filter blood before sending it back to the heart.
They are located on the left and right in the retroperitoneal space, and in adult humans are about 12 centimetres (4 1/2 inches) in length.
They receive blood from the paired renal arteries; blood exits into the paired renal veins.
Each kidney is attached to a ureter, a tube that carries excreted urine to the bladder.
The word “renal” is an adjective meaning “relating to the kidneys”, and its roots are French or late Latin.
Whereas according to some opinions, "renal" should be replaced with "kidney" in scientific writings such as "kidney artery", other experts have advocated preserving the use of renal as appropriate including in "renal artery"
Why are the kidneys important?
Your kidneys remove wastes and extra fluid from your body. Your kidneys also remove acid that is produced by the cells of your body and maintain a healthy balance of water, salts, and minerals such as sodium, calcium, phosphorus, and potassium in your blood.
Without this balance, nerves, muscles, and other tissues in your body may not work normally.
Your kidneys also make hormones that help control your blood pressure make red blood cells
keep your bones strong and healthy.
How do my kidneys work?
Each of your kidneys is made up of about a million filtering units called nephrons. Each nephron includes a filter, called the glomerulus, and a tubule. The nephrons work through a two-step process: the glomerulus filters your blood, and the tubule returns needed substances to your blood and removes wastes.
Drawing of a nephron showing that a blood vessel from the renal artery leads to the glomerulus before branching across the u-shaped tubule and leading to the renal vein.
Each nephron has a glomerulus to filter your blood and a tubule that returns needed substances to your blood and pulls out additional wastes. Wastes and extra water become urine.
The glomerulus filters your blood
As blood flows into each nephron, it enters a cluster of tiny blood vessels the glomerulus. The thin walls of the glomerulus allow smaller molecules, wastes, and fluid mostly water to pass into the tubule. Larger molecules, such as proteins and blood cells, stay in the blood vessel.
The tubule returns needed substances to your blood and removes wastes
A blood vessel runs alongside the tubule. As the filtered fluid moves along the tubule, the blood vessel reabsorbs almost all of the water, along with minerals and nutrients your body needs. The tubule helps remove excess acid from the blood. The remaining fluid and wastes in the tubule become urine.
How does blood flow through my kidneys?
Blood flows into your kidney through the renal artery. This large blood vessel branches into smaller and smaller blood vessels until the blood reaches the nephrons. In the nephron, your blood is filtered by the tiny blood vessels of the glomeruli and then flows out of your kidney through the renal vein.
Your blood circulates through your kidneys many times a day. In a single day, your kidneys filter about 150 quarts of blood. Most of the water and other substances that filter through your glomeruli are returned to your blood by the tubules. Only 1 to 2 quarts become urine.
Blood flows into your kidneys through the renal artery and exits through the renal vein. Your ureter carries urine from the kidney to your bladder.
♦️ Nephrons
Nephrons are the most important part of each kidney. They take in blood, metabolize nutrients, and help pass out waste products from filtered blood. Each kidney has about 1 million nephrons. Each has its own internal set of structures.
♦️ Renal corpuscle
After blood enters a nephron, it goes into the renal corpuscle, also called a Malpighian body. The renal corpuscle contains two additional structures:
1.The glomerulus
This is a cluster of capillaries that absorb protein from blood traveling through the renal corpuscle.
2.The Bowman capsule
The remaining fluid, called capsular urine, passes through the Bowman capsule into the renal tubules.
♦️ Renal tubules
The renal tubules are a series of tubes that begin after the Bowman capsule and end at collecting ducts.
Each tubule has several parts:
- Proximal convoluted tubule
This section absorbs water, sodium, and glucose back into the blood.
This section further absorbs potassium, chloride, and sodium into the blood.
This section absorbs more sodium into the blood and takes in potassium and acid.
By the time fluid reaches the end of the tubule, it’s diluted and filled with urea. Urea is byproduct of protein metabolism that’s released in urine.
♦️ Renal cortex
The renal cortex is the outer part of the kidney. It contains the glomerulus and convoluted tubules.
The renal cortex is surrounded on its outer edges by the renal capsule, a layer of fatty tissue. Together, the renal cortex and capsule house and protect the inner structures of the kidney.
♦️ Renal medulla
The renal medulla is the smooth, inner tissue of the kidney. It contains the loop of Henle as well as renal pyramids.
♦️ Renal pyramids
Renal pyramids are small structures that contain strings of nephrons and tubules. These tubules transport fluid into the kidney. This fluid then moves away from the nephrons toward the inner structures that collect and transport urine out of the kidney.
♦️ Collecting ducts
There’s a collecting duct at the end of each nephron in the renal medulla. This is where filtered fluids exit the nephrons.
Once in the collecting duct, the fluid moves on to its final stops in the renal pelvis.
♦️ Renal pelvis
The renal pelvis is a funnel-shaped space in the innermost part of the kidney. It functions as a pathway for fluid on its way to the bladder
♦️ Calyces
The first part of the renal pelvis contains the calyces. These are small cup-shaped spaces that collect fluid before it moves into the bladder. This is also where extra fluid and waste become urine.
♦️ Hilum
The hilum is a small opening located on the inner edge of the kidney, where it curves inward to create its distinct beanlike shape. The renal pelvis passes through it, as well as the:
This brings oxygenated blood from the heart to the kidney for filtration.
Renal vein. This carries filtered blood from the kidneys back to the heart.
The ureter is a tube of muscle that pushes urine into the bladder, where it collects and exits the body.
The kidneys perform many crucial functions, including:
- 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
Kidney conditions
Because of all of the vital functions the kidneys perform and the toxins they encounter, the kidneys are susceptible to various problems.
Some of these conditions include:
- chronic kidney disease
- kidney failure
- kidney stones
- glomerulonephritis
- acute nephritis
- polycystic kidney disease
- urinary tract infections
- caliectasis
- acidosis
- uremia
- hydronephrosis
- pyelonephritis
- kidney cysts
- nephrotic syndrome
- azotemia
Symptoms of a kidney problem
Kidney conditions can cause a range of symptoms. Some common ones include:
- trouble sleeping
- fatigue
- inability to concentrate
- dry, itchy skin
- increased or decreased urination
- blood in urine
- foamy urine
- puffiness around the eyes
- foot or ankle swelling
- reduced appetite
- muscle cramps
If you notice any of these symptoms, contact your doctor. Depending on your symptoms, they may do some kidney function tests to make a diagnosis.
Tips for healthy kidneys
The kidneys are important organs that affect many other body parts, including the heart. Follow these tips to keep them working efficiently:
Eating a lot of salty foods can disrupt the balance of minerals in the blood. This can make it harder for the kidneys to work properly. Try swapping out processed foods — which usually have a lot of added salt — for whole foods, such as:
- fresh fruits and vegetables:
High blood pressure is a known risk factor for chronic kidney disease. Regular exercise, even for just 20 minutes a day, can help reduce blood pressure.
Drinking plenty of water helps the kidneys perform one of their most important functions: removing toxins. Learn more about how much water you should really be drinking every day.
- Use medications with caution:
Regularly taking certain over-the-counter medications, such as nonsteroidal anti-inflammatory drugs, can cause kidney damage over time. Occasionally taking them is fine, but work with your doctor to find alternatives if you have a condition that requires managing pain, such as arthritis.
Comments
Post a Comment