File Name: kidney structure and function .zip
There have never been sufficient kidney donations to provide a kidney to each person needing one. In this video, Dr.
The kidneys are a pair of bean-shaped structures that are located just below and posterior to the liver in the peritoneal cavity. Adrenal glands, also called suprarenal glands, sit on top of each kidney. All the blood in the human body is filtered many times a day by the kidneys. These organs use almost 25 percent of the oxygen absorbed through the lungs to perform this function.
Figure 1. Kidneys filter the blood, producing urine that is stored in the bladder prior to elimination through the urethra. The kidneys , illustrated in Figure 1, 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. Externally, the kidneys are surrounded by three layers, illustrated in Figure 2. The outermost layer is a tough connective tissue layer called the renal fascia.
The second layer is called the perirenal fat capsule , which helps anchor the kidneys in place. The third and innermost layer is the renal capsule. Internally, the kidney has three regions—an outer cortex , a medulla in the middle, and the renal pelvis in the region called the hilum of the kidney.
The hilum is the concave part of the bean-shape where blood vessels and nerves enter and exit the kidney; it is also the point of exit for the ureters. The renal cortex is granular due to the presence of nephrons —the functional unit of the kidney. The medulla consists of multiple pyramidal tissue masses, called the renal pyramids.
In between the pyramids are spaces called renal columns through which the blood vessels pass. The tips of the pyramids, called renal papillae, point toward the renal pelvis. There are, on average, eight renal pyramids in each kidney. The renal pyramids along with the adjoining cortical region are called the lobes of the kidney. The renal pelvis leads to the ureter on the outside of the kidney. On the inside of the kidney, the renal pelvis branches out into two or three extensions called the major calyces , which further branch into the minor calyces.
The ureters are urine-bearing tubes that exit the kidney and empty into the urinary bladder. Figure 2. The internal structure of the kidney is shown. Because the kidney filters blood, its network of blood vessels is an important component of its structure and function. The arteries, veins, and nerves that supply the kidney enter and exit at the renal hilum. Renal blood supply starts with the branching of the aorta into the renal arteries which are each named based on the region of the kidney they pass through and ends with the exiting of the renal veins to join the inferior vena cava.
The renal arteries split into several segmental arteries upon entering the kidneys. Each segmental artery splits further into several interlobar arteries and enters the renal columns, which supply the renal lobes. The interlobar arteries split at the junction of the renal cortex and medulla to form the arcuate arteries. Cortical radiate arteries , as the name suggests, radiate out from the arcuate arteries.
The cortical radiate arteries branch into numerous afferent arterioles, and then enter the capillaries supplying the nephrons. Veins trace the path of the arteries and have similar names, except there are no segmental veins. As mentioned previously, the functional unit of the kidney is the nephron, illustrated in Figure 3.
Each kidney is made up of over one million nephrons that dot the renal cortex, giving it a granular appearance when sectioned sagittally. There are two types of nephrons— cortical nephrons 85 percent , which are deep in the renal cortex, and juxtamedullary nephrons 15 percent , which lie in the renal cortex close to the renal medulla. A nephron consists of three parts—a renal corpuscle , a renal tubule , and the associated capillary network, which originates from the cortical radiate arteries.
Figure 3. The nephron is the functional unit of the kidney. The glomerulus and convoluted tubules are located in the kidney cortex, while collecting ducts are located in the pyramids of the medulla. The renal tubule is a long and convoluted structure that emerges from the glomerulus and can be divided into three parts based on function. The first part is called the proximal convoluted tubule PCT due to its proximity to the glomerulus; it stays in the renal cortex.
The second part is called the loop of Henle , or nephritic loop, because it forms a loop with descending and ascending limbs that goes through the renal medulla. The third part of the renal tubule is called the distal convoluted tubule DCT and this part is also restricted to the renal cortex. The DCT, which is the last part of the nephron, connects and empties its contents into collecting ducts that line the medullary pyramids.
The collecting ducts amass contents from multiple nephrons and fuse together as they enter the papillae of the renal medulla. The capillary network that originates from the renal arteries supplies the nephron with blood that needs to be filtered.
The branch that enters the glomerulus is called the afferent arteriole. The branch that exits the glomerulus is called the efferent arteriole. Within the glomerulus, the network of capillaries is called the glomerular capillary bed. Once the efferent arteriole exits the glomerulus, it forms the peritubular capillary network , which surrounds and interacts with parts of the renal tubule.
In juxtamedullary nephrons, the peritubular capillary network forms a network around the loop of Henle and is called the vasa recta. Improve this page Learn More. Skip to main content. Module The Excretory System. Search for:. Kidney Structure Learning Outcomes Describe the structure of the kidneys and the functions of the parts of the kidney.
Practice Question Which of the following statements about the kidney is false? The renal pelvis drains into the ureter. The renal pyramids are in the medulla.
The cortex covers the capsule. Nephrons are in the renal cortex. Show Answer Statement c is false. Practice Question Which of the following statements about the nephron is false? The collecting duct empties into the distal convoluted tubule. The loop of Henle is between the proximal and distal convoluted tubules. The loop of Henle empties into the distal convoluted tubule. Show Answer Statement a is false. Go to this website to see another coronal section of the kidney and to explore an animation of the workings of nephrons.
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Click Image to Enlarge. The body takes nutrients from food and changes 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 get rid of liquid waste called urea. 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 blood to the kidneys.
Part III is devoted to such topics as the control of the This content is PDF only. To continue reading please click on the PDF icon. Previous.
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. The kidneys help keep extracellular fluid from becoming too dilute or concentrated with respect to the solutes carried in the fluid. Regulation of ion concentrations.
The kidneys are two reddish-brown bean-shaped organs found in vertebrates. Each kidney is attached to a ureter , a tube that carries excreted urine to the bladder. The nephron is the structural and functional unit of the kidney.
Figure 1. Kidneys filter the blood, producing urine that is stored in the bladder prior to elimination through the urethra. The kidneys , illustrated in Figure 1, 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.
The kidneys are a pair of bean-shaped organs present in all vertebrates. They remove waste products from the body, maintain balanced electrolyte levels, and regulate blood pressure. The kidneys are some of the most important organs.
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The first module focuses on the structure and function of the kidney. The main functions of the kidneys are the reabsorption of solutes and water, production of.Amadeo A. 29.03.2021 at 04:39
PDF | In this chapter we explain: The basic anatomy and physiology of the kidney How kidney function changes through life | Find, read and cite.