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What Are The Three Main Regions Of The Kidney

Regions Of The Digestive System

Structure of kidney | Nephron structure and function

At its simplest, the digestive system is a tube running from mouth to anus. Its chief goal is to break down huge macromolecules , which cannot be absorbed intact, into smaller molecules that can be absorbed across the wall of the tube, and into the circulatory system for dissemination throughout the body.

Regions of the digestive system can be divided into two main parts: the alimentary tract and accessory organs. The alimentary tract of the digestive system is composed of the mouth, pharynx, esophagus, stomach, small and large intestines, rectum and anus. Associated with the alimentary tract are the following accessory organs: salivary glands, liver, gallbladder, and pancreas.

To learn more about the regions of the digestive system, use the hyperlinks listed below to branch into a specific topic.

  • Alimentary Tract of the Digestive System
  • The Kidneys And Osmoregulatory Organs

    • Explain how the kidneys serve as the main osmoregulatory organs in mammalian systems
    • Describe the structure of the kidneys and the functions of the parts of the kidney
    • Describe how the nephron is the functional unit of the kidney and explain how it actively filters blood and generates urine
    • Detail the three steps in the formation of urine: glomerular filtration, tubular reabsorption, and tubular secretion

    Although the kidneys are the major osmoregulatory organ, the skin and lungs also play a role in the process. Water and electrolytes are lost through sweat glands in the skin, which helps moisturize and cool the skin surface, while the lungs expel a small amount of water in the form of mucous secretions and via evaporation of water vapor.

    Location Of The Kidneys

    The two bean-shaped kidneys are located high in the back of the abdominal cavity, one on each side of the spine. Both kidneys sit just below the diaphragm, the large breathing muscle that separates the abdominal and thoracic cavities. As you can see in Figure \, the right kidney is slightly smaller and lower than the left kidney. The right kidney is behind the liver, and the left kidney is behind the spleen. The location of the liver explains why the right kidney is smaller and lower than the left.

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    Clinical Relevance: Variation In Arterial Supply To The Kidney

    The kidneys present a great variety in arterial supply; these variations may be explained by the ascending course of the kidney in the retroperitoneal space, from the original embryological site of formation to the final destination . During this course, the kidneys are supplied by consecutive branches of the iliac vessels and the aorta.

    Usually the lower branches become atrophic and vanish while new, higher ones supply the kidney during its ascent. Accessory arteries are common . An accessory artery is any supernumerary artery that reaches the kidney. If a supernumerary artery does not enter the kidney through the hilum, it is called aberrant.

    Collection Of Urine And Excretion

    25.3 Gross Anatomy of the Kidney  Anatomy and Physiology

    By the time the filtrate has passed through the entire renal tubule, it has become the liquid waste known as urine. Urine empties from the distal end of the renal tubule into a collecting duct. From there, the urine flows into increasingly larger collecting ducts. As urine flows through the system of collecting ducts, more water may be reabsorbed from it. This will occur in the presence of antidiuretic hormone from the hypothalamus. This hormone makes the collecting ducts permeable to water, allowing water molecules to pass through them into capillaries by osmosis while preventing the passage of ions or other solutes. As much as three-fourths of the water may be reabsorbed from urine in the collecting ducts, making the urine more concentrated.

    Urine finally exits the largest collecting ducts through the renal papillae. It empties into the renal calyces and finally into the renal pelvis . From there, it travels through the ureter to the urinary bladder for eventual excretion from the body. An average of about 1.5 liters of urine is excreted each day. Normally, urine is yellow or amber in color ). The darker the color, generally the more concentrated the urine is.

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    What Are The Three Regions Of The Kidneys And The Function Of Each

    Get your answer from wikipedia

    There are three major regions of the kidney: Renal cortex, Renal medulla, Renal pelvis.

    Renal cortex:

    The kidney filters blood and sends waste materials to the bladder to become excreted urine. Inside the renal medulla are pyramids, each of which contains thousands of nephrons. Nephrons are made up of a glomerulus, the filtration unit, and tubules, which collect the filtrate to go to the bladder.

    Renal medulla:

    It contains the renal corpuscles and the renal tubules except for parts of the loop of Henle which descend into the renal medulla. It also contains blood vessels and cortical collecting ducts. The renal cortex is the part of the kidney where ultrafiltration occurs. Erythropoietin is produced in the renal cortex.

    Renal pelvis:

    In humans, the renal pelvis is the point where the two or three major calyces join together. It has a mucous membrane is covered with transitional epithelium, and an underlying lamina propria of loose to dense connective tissue. The renal pelvis functions as a funnel for urine flowing to the ureter.

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    Kidneys And Water Balance

    A nephron is the functional unit of the kidneys. Each kidney contains approximately one million such units. A nephron is composed of a glomerulus and a renal tubule . The renal tubule is subdivided further into the proximal convoluted tubule, the loop of Henle, the distal convoluted tubule, and the collecting duct.

    Figure 3. Nephron and juxtaglomerular apparatus.

    The glomeruli filter about 180;l of fluid each day. Up to 9099% of the filtered water is reabsorbed by the renal tubules. It is reabsorbed passively in the proximal convoluted tubules and the descending limbs of the loops of Henle, with down osmotic gradients created by the active transport of sodium and chloride out of the lumina. Water is not permeable in the ascending limb of the loop of Henle and the distal convoluted tubule. The final urine volume is determined by the action of AVP on the collecting ducts.

    S. Akilesh, in, 2014

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    What Are The Symptoms Of Glomerular Disease

    The signs and symptoms of glomerular disease include

    • albuminuria: large amounts of protein in the urine
    • hematuria: blood in the urine
    • reduced glomerular filtration rate: inefficient filtering of wastes from the blood
    • hypoproteinemia: low blood protein
    • edema: swelling in parts of the body

    One or more of these symptoms can be the first sign of kidney disease. But how would you know, for example, whether you have proteinuria? Before seeing a doctor, you may not. But some of these symptoms have signs, or visible manifestations:

    • Proteinuria may cause foamy urine.
    • Blood may cause the urine to be pink or cola-colored.
    • Edema may be obvious in hands and ankles, especially at the end of the day, or around the eyes when awakening in the morning, for example.

    Areas Of The Abdominal Region

    Structures present in 9 Abdominal Regions | Abdomen | Part 4 (Anatomy)

    The region of the trunk that lies between the diaphragm above the pelvic inlet below is referred to as Abdomen that is divided into nine regions by two vertical and two horizontal lines. Each vertical line passes through mid-point between anterior superior iliac spine and symphysis pubis.

    The upper horizontal line meets the 10th costal cartilage on each side whereas the lower horizontal line joins the tubercles on the iliac crests. The Transpyloric Plane that lies at the level of Lumbar plexus L1 passes through the tips of 9th costal cartilages on the two sides . The Inter-cristal plane passes across the highest points on iliac crests.

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    The Function Of A Nephron

    The simplified diagram of a nephron in Figure \ shows how the nephron functions. Blood enters the nephron through an arteriole called the afferent arteriole. Some of the blood next passes through the capillaries of the glomerulus. Any blood that doesnt pass through the glomerulus, as well as blood after it passes through the glomerular capillaries, continues on through an arteriole called the efferent arteriole. The efferent arteriole follows the renal tubule of the nephron, where it continues to play roles in nephron functioning.


    As blood from the afferent arteriole flows through the glomerular capillaries, it is under pressure. Because of the pressure, water and solutes are filtered out of the blood and into the space made by Bowmans capsule. This is the filtration stage of nephron function. The filtered substances, called filtrate, pass into Bowmans capsule and from there into the proximal end of the renal tubule. At this stage, filtrate includes water, salts, organic solids such as nutrients, and waste products of metabolism such as urea.

    Reabsorption and Secretion

    What Is Urine Made Of

    Urine is made of water, urea, electrolytes, and other waste products. The exact contents of urine vary depending on how much fluid and salt you take in, your environment, and your health. Some medicines and drugs are also excreted in urine and can be found in the urine.

    • 94% water
    • .1% uric acid


    As mentioned prior, urine is formed in the nephrons by a three-step process: glomerular filtration, tubular re-absorption, and tubular secretion. The amount of urine varies based on fluid intake and ones environment.

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    Other Functions Of The Kidneys

    Besides filtering blood and forming urine for the excretion of soluble wastes, the kidneys have several vital functions in maintaining body-wide homeostasis. Most of these functions are related to the composition or volume of urine formed by the kidneys. These functions include maintaining the proper balance of water and salts in the body, normal blood pressure, and the correct range of blood pH. Through the processes of absorption and secretion by nephrons, more or less water, salt ions, acids, or bases are returned to the blood or excreted in urine as needed to maintain homeostasis.

    Help With Passage Way Through Kidney

    11.3 kidney

    See tutors like thiscortex.;medullahilusrenal pelvis.;medullary pyramid. . calyxrenal columnafferent arteriole.;glomerulus.;Bowman’s capsule.efferent arteriole. peritubular capillaries;;proximal convoluted tube .;Loop of Henledistal convoluted tube .collecting ducts.;bladderureter.;urethra.;;;;

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    Why This May Matter To You

    The goal of this proposal is to increase equity in access for U.S. kidney transplant candidates. Some areas of the country will see an increase in kidney transplants which means other areas will experience a decrease. Some kidneys would have to travel further than they do today, in order to meet this goal. This change would result in new working relationships between OPOs and transplant centers.

    What Are The Kidneys And What Do They Do

    The two kidneys are bean-shaped organs located just below the rib cage, one on each side of the spine. Every day, the two kidneys filter about 120 to 150 quarts of blood to produce about 1 to 2 quarts of urine, composed of wastes and extra fluid.

    Blood enters the kidneys through arteries that branch inside the kidneys into tiny clusters of looping blood vessels. Each cluster is called a glomerulus, which comes from the Greek word meaning filter. The plural form of the word is glomeruli. There are approximately 1 million glomeruli, or filters, in each kidney. The glomerulus is attached to the opening of a small fluid-collecting tube called a tubule. Blood is filtered in the glomerulus, and extra fluid and wastes pass into the tubule and become urine. Eventually, the urine drains from the kidneys into the bladder through larger tubes called ureters.

    Each glomerulus-and-tubule unit is called a nephron. Each kidney is composed of about 1 million nephrons. In healthy nephrons, the glomerular membrane that separates the blood vessel from the tubule allows waste products and extra water to pass into the tubule while keeping blood cells and protein in the bloodstream.

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    In Which Main Regions Of The Kidney Are The Collecting Ducts And The Loop Of Henle Located

    The collecting ducts and the loop of Henle are located in the medulla of the kidney.


    The kidney consists of the three main regions outer cortex, middle medulla, and the inner renal pelvis regions.

    The main function of filtering and elimination of waste takes place in the medullary regions of the kidney.

    Renal medulla is arranged into renal pyramid like structures. The medulla comprises the collecting ducts, loop of Henle, vasa recta and interstitium.

    The collecting duct or tubule is a long slender twisting tube which collects the fluid from the nephrons and transports to the inner renal pelvis region of the kidney.

    The loop of Henle is a highly convoluted U-shaped tubule with an ascending and a descending limb. This loop facilitates reabsorption of water and sodium ions necessary for the body from the filtrate formed.

    Blood Supply Of The Kidney & Nephrons

    The Urinary System- Kidney Stones

    The kidneys are well vascularized and receive about 25 percent of the cardiac output at rest. Blood enters the kidney via the paired renal arteries that form directly from the descending aorta and each enters the kidney at the renal hila. Once in the kidney, each renal artery first divides into segmental arteries, followed by further branching to form interlobar arteries that pass through the renal columns to reach the cortex . The interlobar arteries, in turn, branch into arcuate arteries, cortical radiate arteries, and then into afferent arterioles. The afferent arterioles deliver blood into a modified capillary bed called the glomerulus which is a component of the functional unit of the kidney called the nephron. There are about 1.3 million nephrons in each kidney and they function to filter the blood. Once the nephrons have filtered the blood, renal veins return blood directly to the inferior vena cava. A portal system is formed when the blood flows from the glomerulus to the efferent arteriole through a second capillary bed, the peritubular capillaries , surrounding the proximal and distal convoluted tubules and the loop of Henle. Most water and solutes are recovered by this second capillary bed. This filtrate is processed and finally gathered by collecting ducts that drain into the minor calyces, which merge to form major calyces; the filtrate then proceeds to the renal pelvis and finally the ureters.

    Figure 25.1.3

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    Nephrons: The Basic Functional Units Of Blood Filtration And Urine Production

    Each kidney contains over 1 million tiny structures called nephrons. The nephrons are located partly in the cortex and partly inside the renal pyramids, where the nephron tubules make up most of the pyramid mass. Nephrons perform the primary function of the kidneys: regulating the concentration of water and other substances in the body. They filter the blood, reabsorb what the body needs, and excrete the rest as urine.

    Kidney Function And Physiology

    Kidneys filter blood in a three-step process. First, the nephrons filter blood that runs through the capillary network in the glomerulus. Almost all solutes, except for proteins, are filtered out into the glomerulus by a process called glomerular filtration. Second, the filtrate is collected in the renal tubules. Most of the solutes get reabsorbed in the PCT by a process called tubular reabsorption. In the loop of Henle, the filtrate continues to exchange solutes and water with the renal medulla and the peritubular capillary network. Water is also reabsorbed during this step. Then, additional solutes and wastes are secreted into the kidney tubules during tubular secretion, which is, in essence, the opposite process to tubular reabsorption. The collecting ducts collect filtrate coming from the nephrons and fuse in the medullary papillae. From here, the papillae deliver the filtrate, now called urine, into the minor calyces that eventually connect to the ureters through the renal pelvis. This entire process is illustrated in Figure \.

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    What Causes Glomerular Disease

    A number of different diseases can result in glomerular disease. It may be the direct result of an infection or a drug toxic to the kidneys, or it may result from a disease that affects the entire body, like diabetes or lupus. Many different kinds of diseases can cause swelling or scarring of the nephron or glomerulus. Sometimes glomerular disease is idiopathic, meaning that it occurs without an apparent associated disease.

    The categories presented below can overlap: that is, a disease might belong to two or more of the categories. For example, diabetic nephropathy is a form of glomerular disease that can be placed in two categories: systemic diseases, since diabetes itself is a systemic disease, and sclerotic diseases, because the specific damage done to the kidneys is associated with scarring.

    What Are The Regions Of The Kidney

    Kidney Cortex And Medulla

    cortex, medulla, and pelvis.The substance, or parenchyma, of the kidney is divided into two major structures: superficial is the renal cortex and deep is the renal medulla.cortex and medulla

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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


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