Kidneys: The Main Osmoregulatory Organ
The kidneys, illustrated in Figure 22.4, are a pair of bean-shaped structures that are located just below and posterior to the liver in the peritoneal cavity. The adrenal glands sit on top of each kidney and are also called the suprarenal glands. Kidneys filter blood and purify it. All the blood in the human body is filtered many times a day by the kidneys these organs use up almost 25 percent of the oxygen absorbed through the lungs to perform this function. Oxygen allows the kidney cells to efficiently manufacture chemical energy in the form of ATP through aerobic respiration. The filtrate coming out of the kidneys is called urine.
How Does Kidney Disease Affect Your Body
Kidney disease can affect you in a number of different ways. These include:
Proteinuria or protein in the urine is frequently the earliest symptom of kidney disease. You will have read, in the previous section, how the kidney works and that the kidney has about a million filters. When the kidney is healthy it allows very little protein into the urine. If these filters become leaky, small amounts of protein will leak into the urine. This is frequently an early sign of kidney trouble long before the kidney function itself begins to deteriorate.
Doctors frequently test patients urine for the presence of blood or protein, to try to detect kidney disease early. There are many causes of protein in the urine, including diabetes and glomerulonephritis. Whilst your doctor will conduct a number of special blood tests, to try to determine the underlying cause, it may be necessary to undergo a kidney biopsy, to establish the exact cause of the protein.
Patients who have very large amounts of protein in the urine, , are described as having nephrotic syndrome. Patients with nephrotic syndrome frequently have swollen legs.
Haematuria or blood in the urine can either be present in amounts that you can see or in amounts that you cannot see in which it is only detected with urine testing. Blood in the urine may not appear red but more like strong tea coloured.
What Is The Role Of The Kidney In Homeostasis
The kidneys play several important roles in maintaining homeostasis, including maintaining the proper blood volume and ion balance as well as removing nitrogenous wastes from the blood. The University of New Mexico explains that the kidneys also play an important role in regulating the bodys pH. The kidney primarily accomplishes these tasks by filtering impurities, metabolic wastes and salt from the blood.
According to the BBC, the kidneys are able to maintain homeostasis in part by varying the concentration of urine. For example, when the amount of water in the blood plasma is low, the kidneys reabsorb water from the urine, returning it to the blood stream. Conversely, when the amount of water in the blood plasma is high, the kidneys do not reabsorb much water, which produces highly dilute urine. Both responses help to keep the bodys water balance within the range of tolerance.
The kidneys must compensate for other biological functions and stimuli that may alter the water balance of the body, thus disrupting homeostasis. The BBC lists several such stimuli, including the external temperature, exercise and salt intake, as having the potential to change the amount of water in the body. For example, during exercise, the bodys temperature rises. The body attempts to compensate for this by sweating. However, sweat results in a net loss of water, which in turn, triggers the kidneys to reabsorb more water from the urine and return it to the bloodstream.
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What Could Go Wrong With The Kidneys
When the kidneys are not working correctly, waste products and excess fluid can build up and the levels of sodium, potassium, phosphate and calcium are not regulated correctly. When these substances gather together, this causes the symptoms of kidney disease, which can include high blood pressure, excessive tiredness, fluid retention and possibly lower back pain.
Kidney damage can occur for a number of reasons diabetes, high blood pressure, infections and a group of diseases that affect the glomerulus. The kidneys also need an adequate supply of blood, so if there is something wrong with the blood vessels to the kidney, such as a narrowing, this will prevent the kidneys from working efficiently.
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.
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Q: First Things First What Are The Kidneys
A: The kidneys are organs shaped like beans and approximately the size of a fist. Theyre located near the middle of your back, just beneath the rib cage.
As for what they are: they essential serve as waste management for the body. As part of the renal system, theyre responsible for sifting waste and extra water out of the blood and then begin the process of moving it out of the body.
Youd probably be surprised just how active the kidneys are normal, healthy kidneys process about a half cup of blood each minute! Thats 720 cups of blood processed through each kidney each day.
What You Need To Know
You have two kidneys, located near the middle of your back, just below the rib cage. Each is about the size of your fist. Tiny structures called nephrons are inside each kidney and they filter the blood. There are about a million of them.
The kidneys are responsible for removing wastes, toxins and extra water from the body balancing important salts and minerals in the blood and releasing hormones to help control blood pressure, manage anemia and help maintain strong bones. The waste and extra water removed by the kidneys become urine. The urine flows through tubes called ureters. It goes to your bladder, which stores the urine until you go to the bathroom.
When the kidneys are damaged, they can’t filter blood as they should. The result can be a build-up of wastes in your body, as well as other problems that can harm your health.
One in three American adults is at high risk for developing kidney disease today. Yet most arent able to identify the signs and symptoms. One in nine American adults has kidney disease and most dont know it.
At first, kidney disease is silent. Symptoms often dont appear until the kidneys are badly damaged. Many people don’t have any symptoms until their kidney disease is advanced. Blood and urine tests are the only way to know if you have kidney disease.
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How Does The Urinary System Work
The urinary system’s function is to filter blood and create urine as a waste by-product. The organs of the urinary system include the kidneys, renal pelvis, ureters, bladder and urethra.
The body takes nutrients from food and converts them to energy. After the body has taken the food components that it needs, waste products are left behind in the bowel and in the blood.
The kidney and urinary systems help the body to eliminate liquid waste called urea, and to keep chemicals, such as potassium and sodium, and water in balance. Urea is produced when foods containing protein, such as meat, poultry, and certain vegetables, are broken down in the body. Urea is carried in the bloodstream to the kidneys, where it is removed along with water and other wastes in the form of urine.
Other important functions of the kidneys include blood pressure regulation and the production of erythropoietin, which controls red blood cell production in the bone marrow. Kidneys also regulate the acid-base balance and conserve fluids.
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
T – removing TOXINS and waste products from the body
B – controlling BLOOD PRESSURE
E – producing the hormone ERYTHROPOIETIN
D – activating vitamin D
Lets take a closer look at each of these functions!
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How Does Blood Flow Through My Kidneys
Blood flows into your kidney through the renalartery. 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.
How Is Chronic Kidney Disease Detected
Early detection and treatment of chronic kidney disease are the keys to keeping kidney disease from progressing to kidney failure. Some simple tests can be done to detect early kidney disease. They are:
It is especially important that people who have an increased risk for chronic kidney disease have these tests. You may have an increased risk for kidney disease if you:
- are older
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Kidney Disease And Disorders
Kidney diseases and kidney problems are usually treated by a nephrologist. Kidney stones are sometimes treated by a urologist. Here is a list of some of the more common kidney problems:
- Glomerulonephritis inflammation of the glomeruli
- Hydronephrosis excessive fluid within the kidney caused by blocked urine flow
- Pyelonephritis infection of the kidney
- Kidney Stones usually form in the kidneys, but can form anywhere in the urinary tract
- Kidney Cancer
- Nephrosis a process that can lead to kidney failure
- Polycystic Kidney Disease a disorder of the kidneys that result in multiple fluid filled cysts within the kidneys tissues
- Renal Hypertension if the kidneys for some reason do not get enough blood, they set off a series of events leading to high blood pressure
- Renal Infarction similar to a heart attack, but in the kidney, caused by blockage of kidney vessels
- Renal Vein clot clot in the vein that carries blood from the kidney, can be fatal
How Do The Kidneys Maintain Homeostasis
The kidneys are essential for cleansing the blood and eliminating urine waste from the body. They also have other important functions that maintain homeostasis in the body including regulating acid-base balance, the concentration of electrolytes, controlling blood pressure, and secreting hormones.
Kidney failure causes a very serious and possibly fatal disruption of homeostasis in the body. Complications include weakness, shortness of breath, widespread swelling , metabolic acidosis, and heart arrhythmias.
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Kidney And Urinary System Parts And Their Functions
Two kidneys. This pair of purplish-brown organs is located below the ribs toward the middle of the back. Their function is to:
Remove waste products and drugs from the body
Balance the body’s fluids
Release hormones to regulate blood pressure
Control production of red blood cells
The kidneys remove urea from the blood through tiny filtering units called nephrons. Each nephron consists of a ball formed of small blood capillaries, called a glomerulus, and a small tube called a renal tubule. Urea, together with water and other waste substances, forms the urine as it passes through the nephrons and down the renal tubules of the kidney.
Two sphincter muscles. These circular muscles help keep urine from leaking by closing tightly like a rubber band around the opening of the bladder.
Nerves in the bladder. The nerves alert a person when it is time to urinate, or empty the bladder.
Urethra. This tube allows urine to pass outside the body. The brain signals the bladder muscles to tighten, which squeezes urine out of the bladder. At the same time, the brain signals the sphincter muscles to relax to let urine exit the bladder through the urethra. When all the signals occur in the correct order, normal urination occurs.
Why Are The Kidneys So Important
Most people know that a major function of the kidneys is to remove waste products and excess fluid from the body. These waste products and excess fluid are removed through the urine. The production of urine involves highly complex steps of excretion and re-absorption. This process is necessary to maintain a stable balance of body chemicals.
The critical regulation of the body’s salt, potassium and acid content is performed by the kidneys. The kidneys also produce hormones that affect the function of other organs. For example, a hormone produced by the kidneys stimulates red blood cell production. Other hormones produced by the kidneys help regulate blood pressure and control calcium metabolism.
The kidneys are powerful chemical factories that perform the following functions:
- remove waste products from the body
- remove drugs from the body
- balance the body’s fluids
- release hormones that regulate blood pressure
- produce an active form of vitamin D that promotes strong, healthy bones
- control the production of red blood cells
Below you will find more information about the kidneys and the vital role they play in keeping your body functioning.
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Keeping Your Kidneys Healthy
Well-functioning kidneys are essential to your overall health. Early detection of kidney disease can be life-saving. Medication and changes to lifestyle, along with an early referral to a kidney specialist, can prevent or delay kidney failure.
If you are at increased risk of chronic kidney disease, talk to your doctor about having a regular kidney health check.
Functional Structure Of The Kidneys
1. The tubule begins with a hollow enlargement called Bowman’s capsule, which is where water and solutes initially enter the tubule from the bloodstream. This process is known as filtration. The structure comprised of Bowman’s capsule and associated capillaries is called the renal corpuscle.
2. From Bowman’s capsule the tubular fluid flows towards the proximal tubule, which remains in the outer layer of the kidney. The proximal tubule is the major site of reabsorption of water and solutes in equal proportions from the filtered tubular fluid.
3. Then the tubule dips into the hairpin loop of Henle, which descends toward the center of the kidney and then rises back to the cortex. The loop of Henle is also a major site of reabsorption, but unlike the proximal tubule, proportionately more solute than water is reabsorbed, so the tubular fluid is dilute relative to plasma by the end of this segment.
4. The next segment is the distal tubule, which like the proximal tubule remains in the cortex. Both reabsorption and secretion take place in this segment, which is where sodium and potassium concentrations and the pH of the tubular fluid are adjusted to ensure homeostasis.
1. An afferent arteriole takes blood to the renal corpuscle, where the blood passes through the first capillary bed, a ball-shape tuft known as the glomerulus.
2. An efferent arteriole takes blood away from the glomerulus.
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How Do The Kidneys Work
Kidneys take between 120 to 150 quarts of blood and produce nearly 2 quarts of urine and waste daily. As natural filters, waste and urine that pass through the kidneys go into the bladder through the ureters. During this process, the muscles that surround the bladder gradually relax allowing the urine to fill the bladder. Once full, the bladder sends signals that it is time to release the urine from the body.
Your kidneys are one of the most complicated systems in your body. Millions of small filters, or units called nephrons, each filled with a small amount of blood make up your kidneys. Healthy kidneys will filter out urine, wastes, and other harmful toxins through these units while at the same time, the units will retain healthy blood cells, vitamins, minerals, and other important proteins. Without acceptable care of the kidneys by drinking enough water and a maintaining a healthy diet, the kidneys can easily cause problems for the entire body.
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.
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Q: How Do The Kidneys Work
A: The kidneys work with precision! Each kidney contains around a million filtering units called nephrons, which contain a filter and a tubule. These two parts work together the glomerulus filters the blood and the tubule returns the necessary substances back to the blood while removing the waste.
To break that down even more, as blood flows into a nephron, it first enters through the glomerulus, which is a filter made up of tiny blood vessels. The tiny walls of the filter allow small particles, waste and water to flow through, but not larger molecules like proteins and blood cells.
The filtered substances flow through to the tubules, which remove excess acid while retaining minerals and nutrients the body needs. The remaining fluid and waste turn into urine, which rests in the bladder and will eventually leave the body.