Function of kidney

You have two kidneys. Each kidney is about the size of your fist. They are located near the middle of your back, just below the rib cage. Healthy kidneys do many important jobs. For example, kidneys: • Remove waste products and extra water from your body • Help control blood pressure • Help make red blood cells • Help keep bones healthy Each of your kidneys has about 1.5 million filters called nephrons. Nephrons remove wastes and extra fluid from your blood in the form of urine. The urine flows through two tubes, called ureters, to the bladder. The urine is stored there until you go to the bathroom. The wastes come from the breakdown of what you eat or drink, medicine you take, plus normal muscle activity.

The kidneys are a pair of bean-shaped organs located below the rib cage, one on each side of the spine. The kidneys help remove waste products from the body, maintain balanced electrolyte levels, and regulate blood pressure. The kidneys are some of the most important organs in the body. The ancient Egyptians left only the brain and kidneys in position before embalming a body, inferring that they held a higher value than other organs. In this article, we look at the structure and function of the kidneys, the diseases that affect them, and how to keep them healthy. The kidneys are two bean-shaped organs that are roughly the size of a fist. A tough, fibrous renal capsule surrounds each kidney and provides support for the soft tissue inside. Beyond that, two layers of fat serve as further protection. The adrenal glands lie on top of the kidneys. Inside the kidneys are a number of pyramid-shaped lobes. Each consists of an outer renal cortex and an inner renal medulla. Nephrons flow between these sections. Each nephron includes a filter, called the glomerulus, and a tubule. The glomerulus filters blood, which enters the kidneys through the renal arteries and leaves through the renal veins. The kidneys are relatively small organs, but they receive The tubule returns necessary substances to the blood and removes waste that then becomes urine. The kidneys excrete urine through the ureter, a tube that leads to the bladder. What does a kidney look like? The main role of the kidneys i...

Kidney cross section The kidneys remove waste and excess fluid from the blood through structures called nephrons. Each nephron contains a filter called a glomerulus that has a network of tiny blood vessels called capillaries. When blood flows into a glomerulus, tiny molecules — water, essential minerals and nutrients, and wastes — pass through the capillary walls. Large molecules, such as proteins and red blood cells, do not. The filtered solution then passes into another part of the nephron called the tubule. The water, nutrients and minerals that the body needs are transferred back to the bloodstream. The excess water and waste become urine that flows to the bladder. Acute kidney failure occurs when your kidneys suddenly become unable to filter waste products from your blood. When your kidneys lose their filtering ability, dangerous levels of wastes may accumulate, and your blood's chemical makeup may get out of balance. Acute kidney failure — also called acute renal failure or acute kidney injury — develops rapidly, usually in less than a few days. Acute kidney failure is most common in people who are already hospitalized, particularly in critically ill people who need intensive care. Symptoms Signs and symptoms of acute kidney failure may include: • Decreased urine output, although occasionally urine output remains normal • Fluid retention, causing swelling in your legs, ankles or feet • Shortness of breath • Fatigue • Confusion • Nausea • Weakness • Irregular heartbea...

Most people know that the primary function of the kidneys is to eliminate waste products from the body by flushing them out with urine. However, did you know that there are at least 6 other fabulous functions you should thank your kidneys for? A wet bed: the 7 functions of the kidneys An easy way to memorize the 7 different roles that the kidneys play in human health, medical students all around the world often use a simple and funny mnemonic formula: A WET BED. A - controlling ACID-base balance W - controlling WATER balance E - maintaining ELECTROLYTE balance T - removing TOXINS and waste products from the body B - controlling BLOOD PRESSURE E - producing the hormone ERYTHROPOIETIN D - activating vitamin D Let’s take a closer look at each of these functions! Controlling acid-base balance The acids and bases in the human body are always in a state of delicate equilibrium reflected by a parameter known as pH. The normal pH of the blood is 7.35 to 7.45. To maintain this healthy range, the kidneys excrete acids and bases when there’s an excess of them, or retain these compounds when the body is lacking them. Controlling water balance The kidneys are one of the body’s main ways to maintain a stable water balance. By regulating the volume of urine they produce, the kidneys adapt to one’s hydration level. When you drink a lot, the kidneys produce more urine, and the opposite happens when you are dehydrated. Maintaining electrolyte balance The kidneys filter some electrolytes fro...

Most people have two kidneys, each about the size of an adult fist, located on either side of the spine just below the rib cage. Although they are small, your kidneys do many • Removing natural waste products and extra water from your body • Helping make red blood cells • Balancing important minerals in your body • Helping maintain your blood pressure • Keeping your bones healthy Your healthcare provider will order tests every so often to check on your kidney health. The specific test(s) they order depends on any symptoms you may have and other factors. The information below serves as a quick guide to the different tests that your healthcare provider might order to check your kidney health. Serum creatinine lower number is better. High creatinine levels can be a sign of Cystatin C For this test, a lower number is better. Estimated glomerular filtration rate (eGFR) The higher number is better. In general, an eGFR value lower than 60 is a sign that the kidneys may not be working properly. An eGFR lower than 15 is a marker of kidney failure. In less common situations where a more accurate measure of your kidney function is needed, your healthcare provider may order a Blood urea nitrogen (BUN) Urea nitrogen is a waste product in your blood that comes from the breakdown of protein in the foods you eat. It is removed from the body through the kidneys. A “normal” BUN level varies, and usually increases as you get older. Checking your BUN level is usually not very helpful by itsel...

Effect of tubular reabsorption on urine (illustrative 24-hour figures) glomerular filtrate urine tubular reabsorption (percent) water 170 l 1.5 99.1 glucose 170 g — 100 sodium 560 g 5 g 99.1 chloride 620 g 9 g 98.5 phosphate 5.1 g 1.2 g 76.5 calcium 17 g 0.2 g 98.8 urea 51 g 30 g 41.4 sulfate 3.4 g 2.7 g 20.6 It is apparent that the filtrate must be modified in the tubules to account for the differing As the filtrate passes along the Reabsorption affects all the glucose of the filtrate, up to 70 percent of its water and sodium (the remainder is absorbed in the distal tubule), most of the potassium and chloride The tubule has only a certain capacity for reabsorption. Thus, normally all the The reabsorption of about 70 percent of the The active reabsorption of sodium (a positively charged ion) into the blood leaves the fluid remaining in the proximal tubule electronegative with respect to the peritubular fluids. This provides a driving force for the reabsorptive transport of negatively charged ions such as chloride, bicarbonate, and organic solutes. Reabsorption of neutral molecules such as urea into the blood is also driven by active sodium transport. Because the tubular epithelium is less permeable to urea and creatinine than it is to water or chloride, however, the free passive movement of water out of the tubular lumen leads to a rising luminal concentration of urea (i.e., above the concentration in the original filtrate with plasma). As a result, a smaller proportion of...