a&p test 3

Another name for the glomerular capsule is _____ capsule.

Bowman's

letters k,l,m labels ... in the correct order

calyx minor, calyx major, and renal pelvis

what does line M point to?

collecting duct

Increased secretion of hydrogen ions would result in a(n) ______________ of blood ____________?

decrease, pH

As body cells carry out metabolic activities, they consume oxygen and nutrients and produce products such as hormones, cytokines, antibodies and ADH. These substances must be eliminated from the body because they can be toxic to cells if they accumulate.

false

By separately regulating loss of water and loss of solutes in the urine, the kidneys maintain a relatively constant blood osmolarity close to 300 milliosmoles per liter (mOsm/liter) which is hypertonic to the intracellular fluid of the cells.

false

By separately regulating loss of water and loss of solutes in the urine, the kidneys maintain a relatively constant blood osmolarity close to 300 milliosmoles per liter (mOsm/liter) which is hypotonic to the intracellular fluid of the cells.

false

Disposal of wastes through the release of urine is the only purpose of the urinary system.

false

The kidneys adjust blood volume by conserving or eliminating water in the urine. A decrease in blood volume increases blood pressure; an increase in blood volume decreases blood pressure.

false

what is line A pointing to?

fenestration

glomerular capillaries and podocytes together form the

filtration membrane

Blood plasma and dissolved substances with molecules that are smaller than most proteins are filtered directly into the ...........

glomerular capsule

this is the structure of the nephron that filters blood.

glomerulus

the renal cortex is labeled with the letter

letter A (arrow)

the renal cortical column is labeled with the letter

letter C (arrow)

What line is pointing to the capillary basement membrane?

letter D

Where is the distal convoluted tubule?

letter D

Where is the corticomedullary junction?

letter J

where is the ascending limb of the nephron Hanleys loop?

letter L

which part of the nephron reabsorbs the most substances?

proximal convoluted tubule

This term means the return of substances into the blood stream from the filtrate or tubular fluid.

reabsorption

which is not a major function of the kidney?

regulation of blood cell size

The portion of the kidney that extends between the renal pyramids is called the.........

renal columns

the kidneys release ___ to raise blood pressure.

renin

the name of the process when substance from the blood entering the already formed filtrate...

secretion

What type of cells are found in the proximal convoluted tubule?

simple cuboidal

This occurs when a substance passes from the fluid in the tubular lumen through the apical membrane, across the cytosol, and then into the interstitial fluid.

transcellular reabsorption

15-20% of the nephrons are juxtamedullary nephrons. Their renal corpuscles lie in the cortex, close to the medulla, and they have a long nephron loop that extends into the deepest region of the medulla. Long nephron loops receive their blood supply from peritubular capillaries and from the vasa recta that arise from efferent arterioles.

true

A frontal section through the kidney reveals two distinct regions: a superficial, light red region called the renal cortex and a deep, darker reddish-brown inner region called the renal medulla.

true

About 80-85% of the nephrons are cortical nephrons. Their renal corpuscles lie in the outer portion of the renal cortex, and they have short nephron loops that lie mainly in the cortex and penetrate only into the outer region of the renal medulla. The short nephron loops receive their blood supply from peritubular capillaries that arise from efferent arterioles.

true

An analysis of the volume and physical, chemical, and microscopic properties of urine, called a urinalysis, reveals much about the state of the body.

true

An efferent arteriole carries blood out of the glomerulus. Glomerular capillaries are unique among capillaries in the body because they are positioned between two arterioles, rather than between an arteriole and a venule

true

As body cells carry out metabolic activities, they consume oxygen and nutrients and produce waste products such as carbon dioxide, urea, creatinine and uric acid. Wastes must be eliminated from the body because they can be toxic to cells if they accumulate.

true

Because the kidneys remove wastes from the blood and regulate its volume and ionic composition, they are abundantly supplied with blood vessels.

true

Blood plasma is filtered in the glomerular capsule, and then the filtered fluid passes into the renal tubule, which has three main sections. In the order that fluid passes through them, the renal tubule consists of a (1) proximal convoluted tubule (PCT), (2) nephron loop (loop of Henle), and (3) distal convoluted tubule (DCT).

true

By filtering, reabsorbing, and secreting, nephrons help maintain homeostasis of the blood's volume and composition. The situation is somewhat analogous to a recycling center: Garbage trucks dump garbage into an input hopper, where the smaller garbage passes onto a conveyor belt (glomerular filtration of plasma). As the conveyor belt carries the garbage along, workers remove useful items, such as aluminum cans, plastics, and glass containers (reabsorption). Other workers place additional garbage left at the center and larger items onto the conveyor belt (secretion). At the end of the belt, all remaining garbage falls into a truck for transport to the landfill (excretion of wastes in urine).

true

By forming urine, the kidneys help excrete wastes from the body. Some wastes excreted in urine result from metabolic reactions. These include urea and ammonia from the deamination of amino acids; creatinine from the breakdown of creatine phosphate; uric acid from the catabolism of nucleic acids; and urobilin from the breakdown of hemoglobin.

true

By separately regulating loss of water and loss of solutes in the urine, the kidneys maintain a relatively constant blood osmolarity close to 300 milliosmoles per liter (mOsm/liter) which is isotonic to the intracellular fluid of the cells.

true

By separately regulating loss of water and loss of solutes in the urine, the kidneys maintain a relatively constant blood osmolarity close to 300 milliosmoles per liter (mOsm/liter) which is the typical cytosol osmolarity.

true

The kidneys also help regulate blood pressure by secreting the enzyme renin, which activates the renin-angiotensin-aldosterone pathway. Increased renin causes an increase in blood pressure.

true

The kidneys are located between the levels of the last thoracic and third lumbar vertebrae, a position where they are partially protected by ribs 11 and 12 and are said to be retroperitoneal.

true

The kidneys excrete a variable amount of hydrogen ions (H+) into the urine and conserve bicarbonate ions (HCO−3HCO3−), which are an important buffer of H+ in the blood. Both of these activities help regulate blood pH.

true

The mechanisms that regulate glomerular filtration rate operate in two main ways: (1) by adjusting blood flow into and out of the glomerulus and (2) by altering the glomerular capillary surface area available for filtration.

true

where is the arcuate vein?

Letter H

The kidneys themselves can maintain a constant renal blood flow and GFR despite normal, everyday changes in blood pressure, like those that occur during exercise. This capability is called renal autoregulation and consists of two mechanisms—the myogenic mechanism and tubuloglomerular feedback.

True

Urea, ammonia, creatinine, uric acid, and urobilin are collectively known as nitrogenous wastes because they are waste products that contain nitrogen.

True

Which is the correct order of filtrate flow?

1) glomerular capsule, 2) proximal convoluted tubule (PCT), 3) nephron (Hanley's) loop, 4) distal convoluted tubule (DCT), 5) collecting duct

Which is the correct order of blood flow through the kidneys?

1) renal artery > 2) segmental arteries > 3) interlobar arteries > 4) arcuate arteries > 5) afferent arterioles > 6) glomerular capillaries

The kidneys adjust blood volume by conserving or eliminating water in the urine. An increase in blood volume increases blood pressure; a decrease in blood volume decreases blood pressure.

true

Countercurrent Multiplication is the process by which a progressively increasing osmotic gradient is formed in the interstitial fluid of the renal medulla as a result of countercurrent flow. Countercurrent multiplication involves the long nephron loops of juxtamedullary nephrons: the descending limb of the nephron loop carries tubular fluid from the renal cortex deep into the medulla, and the ascending limb carries it in the opposite direction. Since countercurrent flow through the descending and ascending limbs of the long nephron loop establishes the osmotic gradient in the renal medulla, the long nephron loop is said to function as a countercurrent multiplier. The kidneys use this osmotic gradient to excrete concentrated urine.

true

Disposal of wastes through the release of urine is not the only purpose of the urinary system. The urinary system also helps regulate blood composition, pH, volume, and pressure; maintains blood osmolarity; and produces hormones.

true

Even though your fluid intake can be highly variable, the total volume of fluid in your body normally remains stable. Homeostasis of body fluid volume depends in large part on the ability of the kidneys to regulate the rate of water loss in urine. Normally functioning kidneys produce a large volume of dilute urine when fluid intake is high, and a small volume of concentrated urine when fluid intake is low or fluid loss is large. ADH controls whether dilute urine or concentrated urine is formed. In the absence of ADH, urine is very dilute. However, a high level of ADH stimulates reabsorption of more water into blood, producing a concentrated urine.

true

Extending from each podocyte are thousands of footlike processes termed pedicels that wrap around glomerular capillaries. The spaces between pedicels are the filtration slits. A thin membrane, the slit membrane, extends across each filtration slit; it permits the passage of water, glucose, vitamins, amino acids, very small plasma proteins, ammonia, urea, and ions.

true

Glomerular capillaries present a large surface area for filtration because they are long and extensive. Mesangial cells regulate how much surface area is available. When mesangial cells are relaxed, surface area is maximal, and glomerular filtration is very high. Contraction of mesangial cells reduces the available surface area, and glomerular filtration decreases.

true

Glomerular capillary blood pressure is high. Because the efferent arteriole is smaller in diameter than the afferent arteriole, resistance to the outflow of blood from the glomerulus is high. As a result, blood pressure in glomerular capillaries is considerably higher than in blood capillaries elsewhere in the body. Glomerular capillaries also are about 50 times leakier than blood capillaries in most other tissues, mainly because of their large fenestrations.

true

Glomerular endothelial cells are quite leaky because they have large fenestrations (pores). This size permits all solutes in blood plasma to exit glomerular capillaries but prevents filtration of blood cells. The basement membrane, a layer between the endothelium and the podocytes, allow water and most small solutes to pass through, however, hinders filtration of proteins.

true

Glomerular filtration is the first step of urine production. Water and most solutes in blood plasma move across the wall of glomerular capillaries, where they are filtered and move into the glomerular capsule and then into the renal tubule.

true

In each nephron, the final part of the ascending limb of the Hanley's loop makes contact with the afferent and efferent arterioles of the renal corpuscle. The tubule cells in this region are crowded together and they are known as the macula densa or dense spot. Alongside the macula densa, the wall of the afferent arteriole (and sometimes the efferent arteriole) contains modified smooth muscle fibers called juxtaglomerular cells. Together with the macula densa, they constitute the juxtaglomerular apparatus (JGA).

true

In the proximal convoluted tubule, the cells are simple cuboidal epithelial cells with a prominent brush border of microvilli on their apical surface (surface facing the lumen). These microvilli, like those of the small intestine, increase the surface area for reabsorption and secretion. The descending limb of the nephron loop and the first part of the ascending limb of the nephron loop (the thin ascending limb) are composed of simple squamous epithelium. The thick ascending limb of the nephron loop is composed of simple cuboidal to low columnar epithelium.

true

Nephrons are the functional units of the kidneys. Each nephron consists of two parts: a renal corpuscle, where blood plasma is filtered, and a renal tubule into which the filtered fluid (glomerular filtrate) passes. Closely associated with a nephron is its blood supply. The two components, the glomerulus (capillary network) and the glomerular capsule or Bowman's capsule, a double-walled epithelial cup that surrounds the glomerular capillaries make up a renal corpuscle.

true

The amount of filtrate formed in all renal corpuscles of both kidneys each minute is the glomerular filtration rate (GFR).

true

The ascending limb of the nephron loop of juxtamedullary nephrons consists of two portions: a thin ascending limb followed by a thick ascending limb. The lumen of the thin ascending limb is the same as in other areas of the renal tubule; it is only the epithelium that is thinner. The juxtamedullary nephrons with long Hanley's loops enable the kidneys to excrete very dilute or very concentrated urine.

true

The distal convoluted tubules of several nephrons empty into a single collecting duct (CD). Collecting ducts then unite and converge into large papillary ducts, which drain the urine into the minor calyces. The collecting ducts and papillary ducts extend from the renal cortex through the renal medulla to the renal pelvis. One kidney has about 1 million nephrons, but a much smaller number of collecting ducts and even fewer papillary ducts.

true

The efferent arterioles divide to form the peritubular capillaries, which surround tubular parts of the nephron in the renal cortex. Extending from some efferent arterioles are long, loop-shaped capillaries called vasa recta that supply tubular portions of the nephron in the renal medulla

true

The glomerular (Bowman's) capsule consists of visceral and parietal layers. The visceral layer consists of modified simple squamous epithelial cells called podocytes. The many footlike projections of these cells (pedicels) wrap around the single layer of endothelial cells of the glomerular capillaries and form the inner wall of the capsule.

true

The myogenic mechanism occurs when stretching triggers contraction of smooth muscle cells in the walls of afferent arterioles. In response, smooth muscle fibers in the wall of the afferent arteriole contract, which narrows the arteriole's lumen. As a result, renal blood flow decreases, thus reducing GFR to its previous level. Conversely, when arterial blood pressure drops, the smooth muscle cells are stretched less and thus relax. The afferent arterioles dilate, renal blood flow increases, and GFR increases. The myogenic mechanism normalizes renal blood flow and GFR within seconds after a change in blood pressure.

true

The parietal layer of the glomerular capsule consists of simple squamous epithelium and forms the outer wall of the capsule. Fluid filtered from the glomerular capillaries enters the capsular space, the space between the two layers of the glomerular capsule, which is continuous with the lumen of the renal tubule.

true

The peritubular capillaries eventually reunite to form cortical radiate (interlobular) veins, which also receive blood from the vasa recta. Then the blood drains through the arcuate veins to the interlobar veins running between the renal pyramids. Blood leaves the kidney through a single renal vein that exits at the renal hilum and carries venous blood to the inferior vena cava.

true

The renal corpuscle and both convoluted tubules lie within the renal cortex; the nephron loop extends into the renal medulla, makes a hairpin turn, and then returns to the renal cortex.

true

The third function of nephrons and collecting ducts is tubular secretion, the transfer of materials from the blood and tubule cells into the tubular fluid. Secreted substances include hydrogen ions (H+), K+, ammonium ions (NH+4NH4+), creatinine, and certain drugs such as penicillin. Tubular secretion has two important outcomes: (1) The secretion of H+ helps control blood pH. (2) The secretion of other substances helps eliminate them from the body in urine.

true

The volume of fluid entering the proximal convoluted tubules in just half an hour is greater than the total blood plasma volume because the normal rate of glomerular filtration is so high. The volume of total daily filtrate exceeds 180 liter. Obviously most of this fluid must be returned somehow to the bloodstream. Reabsorption—the return of most of the filtered water and many of the filtered solutes to the bloodstream—is the second basic function of the nephron and collecting duct. Normally, about 99% of the filtered water is reabsorbed. Epithelial cells all along the renal tubule and duct carry out reabsorption, but proximal convoluted tubule cells make the largest contribution.

true

Tubular reabsorption: as filtered fluid flows through the renal tubules and through the collecting ducts, tubule cells reabsorb about 99% of the filtered water and many useful solutes. The water and solutes return to the blood as it flows through the peritubular capillaries and vasa recta.

true

Tubular secretion: as filtered fluid flows through the renal tubules and collecting ducts, the renal tubule and duct cells remove substances such as wastes, drugs, and excess ions from the blood and secrete them into the fluid.

true

Tubuloglomerular feedback, is so named because part of the renal tubules—the macula densa—provides feedback to the glomerulus. When GFR is above normal due to elevated systemic blood pressure, filtered fluid flows more rapidly along the renal tubules. As a result, the proximal convoluted tubule and nephron loop have less time to reabsorb Na+, Cl−, and water. Macula densa cells are thought to detect the increased delivery of Na+, Cl−, and water and to inhibit release of nitric oxide (NO) from cells in the juxtaglomerular apparatus (JGA). Afferent arterioles constrict when the level of NO declines. As a result, less blood flows into the glomerular capillaries, and GFR decreases. When blood pressure falls, causing GFR to be lower than normal, the opposite sequence of events occurs, although to a lesser degree. Tubuloglomerular feedback operates more slowly than the myogenic mechanism.

true

When blood volume and blood pressure decrease, the walls of the afferent arterioles are stretched less, and the juxtaglomerular cells secrete the enzyme renin into the blood. Sympathetic stimulation also directly stimulates release of renin from juxtaglomerular cells. Renin clips off a 10-amino acid peptide called angiotensin I from angiotensinogen, which is synthesized by hepatocytes. By clipping off two more amino acids, angiotensin-converting enzyme (ACE) in the lungs converts angiotensin I to angiotensin II, which is the active form of the hormone. This mechanism is referred to as Renin-Angiotensin-Aldosterone System.

true

Within the kidney, the renal artery divides into several segmental arteries, which supply different segments (areas) of the kidney. Each segmental artery gives off several branches that enter the parenchyma and pass through the renal columns between the renal lobes as the interlobar arteries. At the bases of the renal pyramids, the interlobar arteries arch between the renal medulla and cortex; here they are known as the arcuate arteries. Divisions of the arcuate arteries produce a series of cortical radiate (interlobular) arteries. These arteries radiate outward and enter the renal cortex. Here, they give off branches called afferent arterioles which divides into a tangled, ball-shaped capillary network called the glomerulus.

true

the urinary bladder consists of two kidneys, two ureters, one urinary bladder, and one urethra.

true

which of the following is a waste product of the kidneys

urea, uric acid, creatinin

this transports urine from the kidney to the bladder.

ureter

An analysis of the physical, chemical, and microscopic properties of urine is called .........

urinalysis

The kidneys convert some of the bilirubin from hemoglobin breakdown to ________, a yellow pigment.

urobilin