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1

The two kidneys lie on the ?? wall of the abdomen, outside the ?? cavity . Each kidney of the adult human weighs about 150 grams and is about the size of a clenched fist. The medial side of each kidney contains an indented region called the ??? through which pass the ??? and ????, ???, ????, and ???, which carries the final urine from the kidney to the bladder, where it is stored until the bladder is emptied. The kidney is surrounded by a tough, fibrous ???? that protects its delicate inner structures.

The two kidneys lie on the posterior wall of the abdomen, outside the peritoneal cavity (Figure 26-2). Each kidney of the adult human weighs about 150 grams and is about the size of a clenched fist. The medial side of each kidney contains an indented region called the hilum through which pass the renal artery and vein, lymphatics, nerve supply, and ureter, which carries the final urine from the kidney to the bladder, where it is stored until the bladder is emptied. The kidney is surrounded by a tough, fibrous capsule that protects its delicate inner structures.

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If the kidney is bisected from top to bottom, the two major regions that can be visualized are the outer ???? and the inner ????? regions. The medulla is divided into ?? to ?? cone-shaped masses of tissue called ?????. The base of each pyramid originates at the border between the cortex and medulla and terminates in the ????, which projects into the space of the renal pelvis, a funnel-shaped continuation of the upper end of the ????. The outer border of the pelvis is divided into open-ended pouches called ???? calyces that extend downward and divide into major calyces, which collect urine from the tubules of each papilla. The walls of the calyces, pelvis, and ureter contain ???? elements that propel the urine toward the ???, where urine is stored until it is emptied by ?????

If the kidney is bisected from top to bottom, the two major regions that can be visualized are the outer cortex and the inner medulla regions. The medulla is divided into 8 to 10 cone-shaped masses of tissue called renal pyramids. The base of each pyramid originates at the border between the cortex and medulla and terminates in the papilla, which projects into the space of the renal pelvis, a funnel-shaped continuation of the upper end of the ureter. The outer border of the pelvis is divided into open-ended pouches called minor calyces that extend downward and divide into major calyces, which collect urine from the tubules of each papilla. The walls of the calyces, pelvis, and ureter contain contractile elements that propel the urine toward the bladder, where urine is stored until it is emptied by micturition

3

Blood flow to the two kidneys is normally about ?? percent of the cardiac output, or ?? ml/min. The renal artery eventually turns into the renal vein. What are the intermediate branches?

Blood flow to the two kidneys is normally about 22 percent of the cardiac output, or 1100 ml/min.

Renal artery - segmental arteries - interlobar arteries -arucrate arteries - interlobular arteries - afferent arterioles - glomerular capillaires - efferent arterioles - peritubular capillaries/vasa recta - interlobular veins - arcuate veins - interlobar veins - segemntal veins - renal vein

4

Each human kidney contains about ??? to ?? nephrons, each of which is capable of forming urine.The kidney cannot regenerate new nephrons.

Each human kidney contains about 800,000 to 1,000,000 nephrons, each of which is capable of forming urine.The kidney cannot regenerate new nephrons.

5

Fluid filtered from the glomerular capillaries flows into ???? and then into the ????, which lies in the ??? of the kidney (Figure 26-4). From the here, fluid flows into the ??, which dips into the renal????. Each loop consists of a ?? and an ???. The walls of the ??? and the lower end of the ??? limb are very thin and therefore are called the thin segment of the ????. After the ascending limb of the loop returns partway back to the ???, its wall becomes much ????, and it is referred to as the ????? segment of the ???? limb.

At the end of the ??? limb is a short segment that has in its wall a plaque of specialized epithelial cells, known as the ????. As discussed later, the macula densa plays an important role in controlling nephron function. Fluid enters the ????? tubule, which, like the proximal tubule, lies in the renal ????. This is followed by the ??? and the ??, which lead to the cortical collecting duct. The initial parts of 8 to 10 cortical collecting ducts join to form a single larger collecting duct that runs downward into the ?? and becomes the ????. The collecting ducts merge to form progressively larger ducts that eventually empty into the ??? through the tips of the renal ????. In each kidney, there are about 250 of the very large collecting ducts, each of which collects urine from about 4000 nephrons.

Fluid filtered from the glomerular capillaries flows into bowman's capsule and then into the proximal convoluted tubule , which lies in the cortex of the kidney (Figure 26-4). From the here, fluid flows into the loop of henle, which dips into the renal medulla. Each loop consists of a descending and an ascedning portion. The walls of the descending limb and the lower end of the ascending limb are very thin and therefore are called the thin segment of the loop of henle. After the ascending limb of the loop returns partway back to the cortex, its wall becomes much thicker, and it is referred to as the thick segment of the ascending limb.

At the end of the thick asending  limb is a short segment that has in its wall a plaque of specialized epithelial cells, known as the macula densa. As discussed later, the macula densa plays an important role in controlling nephron function. Fluid enters the distal convultued tubule, which, like the proximal tubule, lies in the renal cortex. This is followed by the collecting tubule and the cortical collecting tubule, which lead to the cortical collecting duct. The initial parts of 8 to 10 cortical collecting ducts join to form a single larger collecting duct that runs downward into the medulla and becomes the medulllary collecting duct. The collecting ducts merge to form progressively larger ducts that eventually empty into the renal pelvis through the tips of the renal papillae. In each kidney, there are about 250 of the very large collecting ducts, each of which collects urine from about 4000 nephrons.

6

The nephrons that have glomeruli located in the outer cortex are called ??? nephrons; they have ??? loops of Henle that penetrate only a short distance into the ???. About 20 to 30 percent of the nephrons have glo­meruli that lie deep in the renal cortex near the medulla and are called ??? nephrons. These nephrons have long loops of Henle that dip deeply into the ????, in some cases all the way to the tips of the renal papillae.

The nephrons that have glomeruli located in the outer cortex are called cortical nephrons; they have short loops of Henle that penetrate only a short distance into the medulla. About 20 to 30 percent of the nephrons have glo­meruli that lie deep in the renal cortex near the medulla and are called juxtamedullary nephrons. These nephrons have long loops of Henle that dip deeply into the me­dulla, in some cases all the way to the tips of the renal papillae.

7

The first step in urine formation is the filtration of large amounts of fluid through the ???? into ????—almost 180 liters each day. Most of this filtrate is???, leaving only about ??? liters of fluid to be excreted each day, although the renal fluid excretion rate may be highly variable depending on fluid intake. The high rate of glomerular filtration depends on a high rate of kidney blood flow.

The first step in urine formation is the filtration of large amounts of fluid through the glomerular capillaries into bowman's capsule—almost 180 liters each day. Most of this filtrate is reabsorbed, leaving only about 1 liters of fluid to be excreted each day, although the renal fluid excretion rate may be highly variable depending on fluid intake. The high rate of glomerular filtration depends on a high rate of kidney blood flow.

8

the glomerular capillaries are relatively impermeable to ???, so the filtered fluid (called the glomerular filtrate) is essentially ???? free and devoid of cellular elements, including ???? cells. The concentrations of other constituents of the glomerular filtrate, including most salts and organic molecules, are similar to the concentrations in the plasma. Exceptions to this generalization include a few low molecular weight substances such as ??? and ??? that are not freely filtered because they are partially bound to the ????.

the glomerular capillaries are relatively impermeable to proteins, so the filtered fluid (called the glomerular filtrate) is essentially protein free and devoid of cellular elements, including red blood cells.

The concentrations of other constituents of the glomerular filtrate, including most salts and organic molecules, are similar to the concentrations in the plasma. Exceptions to this generalization include a few low molecular weight substances such as calcium and fatty acids that are not freely filtered because they are partially bound to the plasma proteins. For example, almost one half of the plasma calcium and most of the plasma fatty acids are bound to proteins, and these bound portions are not filtered through the glomerular capillaries

For example, almost one half of the plasma calcium and most of the plasma fatty acids are bound to proteins, and these bound portions are not filtered through the glomerular capillaries

9

The GFR is determined by  the balance of ???and colloid ???  forces acting across the capillary membrane. In the average adult human, the GFR is about ????ml/min, or ??? L/day. The fraction of the renal plasma flow that is filtered (the filtration fraction) averages about 0.2, which means that about ????percent of the plasma flowing through the kidney is filtered through the glomerular capillaries.

The GFR is determined by  the balance of  hydrostatic and colloid osmotic  forces acting across the capillary membrane. In the average adult human, the GFR is about 100-125ml/min, or 144-180 L/day. The fraction of the renal plasma flow that is filtered (the filtration fraction) averages about 0.2, which means that about 20 percent of the plasma flowing through the kidney is filtered through the glomerular capillaries.

10

The renal corpuscle, the site of formation of the glomerular filtrate, comprises what 3 main structures?

The renal corpuscle, the site of formation of the glomerular filtrate, comprises a glomerulus (capillary bundle), Bowman’s space, and Bowman’s capsule.

11

There are both parietal and visceral layers of bowmans capsule. The pareital layer is ??? epithelium. The visceral layer are made up by the modified epithelial cells that are known as ??. 

Between the lumen of the glomerulus, and the bowman's space of the renal corpuscle, is a critical group of structures known collectively as the ??????. There are 4 elements to this:

  1. A carbohydrate-rich coating known as a ????, that covers the innner surface of the ?? cells.
  2. The ??? cells
  3. The fenestrtaed ???? membrane.
  4. The mofified epithelial cells known as ?

There are both parietal and visceral layers of bowmans capsule. The pareital layer is simple squamous epithelium. The visceral layer are made up by the modified epithelial cells that are known as podocytes.

Between the lumen of the glomerulus, and the bowman's space of the renal corpuscle, is a critical group of structures known collectively as the glomerulalr filtration barrier. There are 4 elements to this:

  1. A carbohydrate-rich coating known as a glycocalyx, that covers the innner surface of the endothelial cells.
  2. The endothelial cells
  3. The fenestrtaed glomerular basement membrane.
  4. The mofified epithelial cells known as podocytes

12

The glycocalyx contains negatively charged ????

GAGs

13

Endothelial cells of the glomerular capillaries are almost completely surrounded by the glomerular basement membrane and a layer of podocyte foot processes. The exception is a small region toward the center of the glomerulus, where the endothelial cells have neither basement membrane nor podocytes and come into direct contact with mesangial cells, which resemble smooth muscle.

14

The basement membrane contains ?????, which helps restrict large, negatively charged solutes.

Heparan sulphate proteoglycans.

15

A special type of cell can be found that support the glomerular capillary loops - these are contractile cells called ???? cells. They secrete a suppotive ????. This network is continuous with the smooth-muscle cells of the afferent and efferent arterioles. The matrix extends to the “extraglomerular” mesangial cells.

The juxtaglomerular apparatus (JGA) includes the extraglomerular mesangial cells, the ???, and the ?????.

 

 

A special type of cell can be found that support the glomerular capillary loops - these are contractile cells called mesnagial cells. They secrete a suppotive extracellular matrix. This network is continuous with the smooth-muscle cells of the afferent and efferent arterioles. The matrix extends to the “extraglomerular” mesangial cells.

The juxtaglomerular apparatus (JGA) includes the extraglomerular mesangial cells, the macula densa, and the granular cells/juxtaglomerular cells.

16

The ???? is a patch of specialized tubule epithelial cells—at the transition between the TAL and the distal tubule—that contacts its own ???? . These cells have strikingly large ???? and are closely packed, and thus they have a plaque-like appearance. The granular cells in the wall of ??? arterioles, also called juxtaglomerular or epithelioid cells, are specialized ??? cells that produce, store, and release the enzyme ????

The macula densa is a patch of specialized tubule epithelial cells—at the transition between the TAL and the distal tubule—that contacts its own glomerulus . These cells have strikingly large nuclei and are closely packed, and thus they have a plaque-like appearance. The granular cells in the wall of afferent arterioles, also called juxtaglomerular or epithelioid cells, are specialized smooth muscle cells that produce, store, and release the enzyme renin

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