Pathophysiology: Chapter 38 Structure and Function of the Renal and Urologic Systems

Question 1

The area of the kidneys that contains the glomeruli and portions of the tubules is called
the:
a. Medulla c. Pyramids
b. Cortex d. Columns

Answer 1

ANS: B
The cortex contains all the glomeruli and portions of the tubules of the kidneys. Although
the other options are also located in the kidney, they do not contain the glomeruli.

Question 2

What is the functional unit of the kidney called?
a. Glomerulus c. Collecting duct
b. Nephron d. Pyramid
.

Answer 2

ANS: B
The nephron is the functional unit of the kidney. Although the other options are also
located in the kidney, they are not its functional units

Question 3

Which cells have phagocytic properties similar to monocytes and contract like smooth
muscles cells, thereby influencing the glomerular filtration rate?
a. Principle cells c. Mesangial cells
b. Podocin cells d. Intercalated cells

Answer 3

ANS: C
Mesangial cells and the mesangial matrix, secreted by mesangial cells, lie between and
support the glomerular capillaries. Different mesangial cells contract like smooth muscle
cells to regulate glomerular capillary blood flow. They also have phagocytic properties
similar to monocytes. The other options are not capable of these functions.

Question 4

The only surface inside the nephron where cells are covered with microvilli to increase the
reabsorptive surface area is called the:
a. Proximal convoluted tubules 
b. Distal tubules 
c. Ascending loop of Henle
d. Descending loop of Henle

Answer 4

ANS: A
The only surface inside the nephron where the cells are covered with microvilli (a brush
border) is called the proximal convoluted tubules. This proximal convoluted tubular lumen
consists of one layer of cuboidal cells with a surface layer of microvilli that increases the
reabsorptive surface area.

Question 5

What part of the kidney controls renal blood flow, glomerular filtration, and renin
secretion?
a. Macula densa 
b. Visceral epithelium
c. Juxtaglomerular apparatus (JGA) 
d. Filtration slits

Answer 5

ANS: C
Control of renal blood flow, glomerular filtration, and renin secretion occur at the JGA.
Together, the juxtaglomerular cells and macula densa cells form the JGA. The control of
renal blood flow, glomerular filtration, and renin secretion is not directed by any of the
other options.

Question 6

Kidney stones in the upper part of the ureter would produce pain referred to which
anatomical area?
a. Vulva or penis c. Thighs
b. Umbilicus d. Lower abdomen

Answer 6

ANS: B
Kidney stones in the upper part of the ureter would produce pain in the umbilicus. Sensory
innervation for the upper part of the ureter arises from the tenth thoracic nerve roots with
referred pain to the umbilicus. The other options would not experience such referred pain.

Question 7

Innervation of the bladder and internal urethral sphincter is supplied by which nerves?

a. Peripheral nerves
b. Parasympathetic fibers
c. Sympathetic nervous system
d. Tenth thoracic nerve roots

Answer 7

ANS: B
The innervation of the bladder and internal urethral sphincter is supplied by
parasympathetic fibers of the autonomic nervous system. The process is not dependent on
any of the other options.

Question 8

How much urine accumulates in the bladder before the mechanoreceptors sense bladder
fullness?
a. 75 to 100 ml c. 250 to 300 ml
b. 100 to 150 ml d. 350 to 400 ml

Answer 8

ANS: C
When the bladder accumulates 250 to 300 ml of urine, it contracts and the internal urethral
sphincter relaxes through activation of the spinal reflex arc (known as the micturition
reflex).

Question 9

What is the trigone?

a. A smooth muscle that comprises the orifice of the ureter
b. The inner mucosal lining of the kidneys
c. A smooth triangular area between the openings of the two ureters and the urethra
d. One of the three divisions of the loop of Henle

Answer 9

ANS: C
The trigone is a smooth triangular area lying between the openings of the two ureters and
the urethra. The other options do not accurately identify the trigone.

Question 10

The glomerular filtration rate is directly related to which factor?

a. Perfusion pressure in the glomerular capillaries
b. Diffusion rate in the renal cortex
c. Diffusion rate in the renal medulla
d. Glomerular active transport

Answer 10

ANS: A
The filtration of the plasma per unit of time is known as the glomerular filtration rate
(GFR), which is directly related to only the perfusion pressure in the glomerular
capillaries.

Question 11

On average, what percent of cardiac output do the kidneys receive?

a. 10% to 20% c. 20% to 25%
b. 15% to 20% d. 30% to 35%

Answer 11

ANS: C
The kidneys are highly vascular organs and usually receive 1000 to 1200 ml of blood per
minute, or approximately 20% to 25% of the cardiac output.

Question 12

What effects do exercise and body position have on renal blood flow?
a. Exercise and body position activate renal parasympathetic neurons and cause mild
vasoconstriction.
b. They activate renal sympathetic neurons and cause mild vasoconstriction.
c. Both activate renal parasympathetic neurons and cause mild vasodilation.
d. They activate renal sympathetic neurons and cause mild vasodilation.

Answer 12

ANS: B
Exercise and change of body position activate renal sympathetic neurons and cause mild
vasoconstriction. The other options do not have these effects on renal blood flow.

Question 13

Blood vessels of the kidneys are innervated by the:

a. Vagus nerve
b. Sympathetic nervous system
c. Somatic nervous system
d. Parasympathetic nervous system

Answer 13

ANS: B
The blood vessels of the kidney are innervated by the sympathetic noradrenergic fibers
that cause arteriolar vasoconstriction and reduce renal blood flow. The other options are
not involved in this process.

Question 14

When renin is released, it is capable of which action?

a. Inactivation of autoregulation
b. Direct activation of angiotensin II
c. Direct release of antidiuretic hormone (ADH)
d. Formation of angiotensin I

Answer 14

ANS: D
When renin is released, it cleaves an -globulin (angiotensinogen produced by liver
hepatocytes) in the plasma to form angiotensin I.

Question 15

What effect do natriuretic peptides have during heart failure when the heart dilates?

a. Stimulates antidiuretic hormones. c. Stimulates renin and aldosterone.
b. Inhibits antidiuretic hormones. d. Inhibits renin and aldosterone.

Answer 15

ANS: D
Natriuretic peptides inhibit renin and aldosterone during heart failure when the heart
dilates. These make up a group of peptide hormones, including atrial natriuretic peptide
(ANP), secreted from myocardial cells in the atria and brain natriuretic peptide (BNP)
secreted from myocardial cells in the cardiac ventricles. When the heart dilates during
volume expansion or heart failure, ANP and BNP inhibit sodium and water absorption by
kidney tubules, inhibit the secretion of renin and aldosterone, vasodilate the afferent
arterioles, and constrict the efferent arterioles. The result is increased urine formation,
leading to decreased blood volume and blood pressure.

Question 16

What is the direct action of atrial natriuretic hormone?

a. Sodium retention c. Water retention
b. Sodium excretion d. Water excretion

Answer 16

ANS: B
Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) inhibit the secretion
of renin, inhibit angiotensin-induced secretion of aldosterone, vasodilate the afferent and
constrict the efferent glomerular arterioles, and inhibit sodium and water absorption by
kidney tubules. The other actions are not a result of the atrial natriuretic hormone.

Question 17

What term is used to identify the movement of fluids and solutes from the tubular lumen to
the peritubular capillary plasma?
a. Tubular secretion c. Tubular reabsorption
b. Ultrafiltration d. Tubular excretion

Answer 17

ANS: C
Tubular reabsorption is the movement of fluids and solutes from the tubular lumen to the
peritubular capillary plasma. This selection is the only option that correctly identifies the
process.

Question 18

How high does the plasma glucose have to be before the threshold for glucose is achieved?
a. 126 mg/dl c. 180 mg/dl
b. 150 mg/dl d. 200 mg/dl
d.

Answer 18

ANS: C
When the plasma glucose reaches 180 mg/dl, as occurs in the individual with uncontrolled
diabetes mellitus, the threshold for glucose is achieve

Question 19

Which hormone is required for water to be reabsorbed in the distal tubule and collecting
duct?
a. Antidiuretic hormone c. Cortisol
b. Aldosterone d. Adrenocorticotropin hormone

Answer 19

ANS: A
Antidiuretic hormone is required for water to be reabsorbed in the distal tubule and
collecting duct. The later, straight segment of the distal tubule and the collecting duct are
permeable to water as controlled by antidiuretic hormone. The other options are not
involved in this process.

Question 20

Which glycoprotein protects against urolithiasis and is a ligand for lymphokines?

a. Uromodulin c. Urodilatin
b. Nephrin d. Cystatin

Answer 20

ANS: A
Tamm-Horsfall glycoprotein, also known as uromodulin, is the most abundant urinary
protein, protects against bacterial adhesion and urolithiasis, and is a ligand for
lymphokines. This statement is not true of the other options.

Question 21

What is the end-product of protein metabolism that is excreted in urine?

a. Glucose c. Bile
b. Ketones d. Urea

Answer 21

ANS: D
Of the options available, only urea is an end-product of protein metabolism and is the
major constituent of urine along with water.

Question 22

What is the action of urodilatin?

a. Urodilatin causes vasoconstriction of afferent arterioles.
b. It causes vasodilation of the efferent arterioles.
c. Urodilatin inhibits antidiuretic hormone secretion.
d. It inhibits salt and water reabsorption.

Answer 22

ANS: D
Urodilatin (a natriuretic peptide) inhibits sodium and water reabsorption from the
medullary part of collecting duct, thereby producing diuresis. It is not involved in the
actions described by the other options.

Question 23

The concentration of the final urine is determined by antidiuretic hormone (ADH), which
is secreted by which gland?
a. Posterior pituitary c. Parathyroid
b. Thyroid d. Anterior pituitary

Answer 23

ANS: A
ADH, which is secreted from the posterior pituitary gland, controls the concentration of
the final urine. ADH is not secreted by any of the other options.

Question 24

Which statement is true regarding urodilatin?
a. Urodilatin inhibits sodium chloride and water reabsorption in the medullary part of
the collecting duct.
b. It inhibits antidiuretic hormone (ADH) to prevent water reabsorption in the
medullary part of the collecting duct.
c. Urodilatin is stimulated by a rise in blood pressure and an increase in extracellular
volume.
d. It is stimulated by a fall in blood pressure and a decrease in extracellular volume.

Answer 24

ANS: C
When the circulating volume and increased blood pressure are increased, the distal tubule
and collecting duct produces urodilatin (a natriuretic peptide). Urodilatin inhibits sodium
and water reabsorption from the medullary part of collecting duct, thereby producing
diuresis.

Question 25

What substance stimulates renal hydroxylation in the process of producing vitamin D?

a. Erythropoietin c. Calcitonin
b. Thyroid hormone d. Parathyroid hormone

Answer 25

ANS: D
Parathyroid hormone stimulates renal hydroxylation in the process of producing vitamin
D. The first step occurs in the liver with hydroxylation at the 25th carbon (calcifediol); the
second step in hydroxylation occurs at the first carbon position in the kidneys. The other
options are not involved in this process.

Question 26

Which hormone is synthesized and secreted by the kidneys?

a. Antidiuretic hormone c. Erythropoietin
b. Aldosterone d. Angiotensinogen

Answer 26

ANS: C
Erythropoietin is produced by the fetal liver and in the adult kidney and is essential for
normal erythropoiesis. This statement is not true of the other options.

Question 27

What provides the best estimate of the functioning of renal tissue?

a. Glomerular filtration rate
b. Hourly urine output
c. Serum blood urea nitrogen and creatinine
d. The specific gravity of the solute concentration of the urine

Answer 27

ANS: A
The glomerular filtration rate provides the best estimate of the level of functioning of renal
tissue. The other options are not used to assess renal tissue function.

Question 28

Which renal change is found in older adults?

a. Sharp decline in glomerular filtration rate
b. Sharp decline in renal blood flow
c. Decrease in the number of nephrons
d. Decrease in urine output

Answer 28

ANS: C
With aging, the number of nephrons decreases. The other options are not necessarily
related to aging.

Question 29

Compared with a younger individual, how is the specific gravity of urine in older adults
affected?
a. Specific gravity of urine in older adults is increased.
b. Specific gravity of urine in older adults is considered high normal.
c. Specific gravity of urine in older adults is considered low normal.
d. Specific gravity of urine in older adults is decreased.

Answer 29

ANS: C

The specific gravity of the urine in older individuals tends to be on the low side of normal.

Question 30

What process allows the kidney to respond to an increase in workload?

a. Glomerular filtration
b. Secretion of 1,25-dihydroxyvitamin D3
c. Increased heart rate
d. Compensatory hypertrophy

Answer 30

ANS: D
Compensatory hypertrophy allows the kidney to respond to an increase in workload
throughout life. The remaining options are not relevant to accommodating an increased
workload.

Question 31

Which process makes it possible for ureters to be transplanted successfully?

a. Compensatory hypertrophy c. Peristalsis
b. Erythropoietin secretion d. Collateral circulation

Answer 31

ANS: C
Peristalsis is the process which makes it possible for ureters to be transplanted
successfully. This process is maintained even when the ureter is denervated. The
remaining options are not relevant to transplant success.