Chapter 18 - The Urinary System

Question 1

Which of the following statements concerning the structure of medullary rays is true?
(A) They contain arched collecting tubules.
(B) They contain proximal convoluted
tubules.
(C) They do not extend into the renal cortex.
(D) They lie at the center of a renal lobule.
(E) They contain thin limbs of the loops of
Henle.

Answer 1

D. A medullary ray contains the straight portions of tubules projecting from the medulla into the cortex, giving the appearance of striations or rays. A renal lobule consists of a central medullary ray and its closely associated cortical tissue (see Chapter 18 II E).

Question 2

Which one of the following structures is located in the renal cortex?
(A) Vasa recta
(B) Thin limbs of the loops of Henle
(C) Afferent arterioles
(D) Interlobar veins
(E) Area cribrosa

Answer 2

C. Afferent arterioles, which arise from interlobular arteries and supply the glomerular capillar­ies, are located in the renal cortex (see Chapter 18 III A 5).

Question 3

Which of the following structures is present in the male urethra but is not present in the female urethra?
(A) Stratified squamous epithelium
(B) Transitional epithelium
(C) Glands of Littre
(D) External sphincter of skeletal muscle
(E) Connective tissue layer underlying
the epithelium

Answer 3

B. Only the male urethra contains transitional epithelium (in the prostatic portion). Stratified squamous epithelium lines most of the female urethra and the distal end of the cavernous ure­thra in men. Mucus-secreting glands of Littre are always present in the male urethra and may be present in the female urethra (see Chapter 18 VI D).

Question 4

Which of the following statements concerning cortical collecting tubules is always true?
(A) They are lined by a simple epithelium containing two types of cells.
(B) They are also known as the ducts of Bellini.
(C) They empty on the area cribrosa.
(D) They are permeable to water.
(E) They are continuous with the ascending
thick limb of the Henle loop.

Answer 4

A. Cortical collecting tubules are lined by a simple epithelium containing principal (light) cells and intercalated (dark) cells. They are permeable to water only in the presence ofADH; in the absence of this hormone, they are impermeable to water. The large papillary collect­ ing tubules, called ducts of Bellini, empty on the area cribrosa at the apex of each renal papilla (see Chapter 18 III B).

Question 5

A 35-year-old woman had surgery to remove a cerebral tumor. A month after the procedure, she reports being excessively thirsty and drink­ ing several liters of water per day. She must also urinate so frequently that she avoids leaving the house. Laboratory tests indicate that her urine has very low specific gravity. What is the most likely diagnosis of this woman's condition?
(A) Acute renal failure
(B) Glomerulonephritis
(C) Chronic renal failure
(D) Diabetes insipidus
(E) Urinary incontinence

Answer 5

D. This woman has diabetes insipidus. Surgical removal of the cerebral tumor likely damaged her hypothalamus, which in turn greatly reduced or eliminated the production ofADH. Therefore, her kidney collecting tubules and distal tubules fail to resorb water, resulting in the production of vast quantities of dilute urine and causing excessive thirst (see Chapter 18 V C Clinical Considerations).

Question 6

The countercurrent multiplier system in the kidney involves the exchange of water and ions between the renal interstitium and
(A) the blood in the vasa recta.
(B) the blood in the peritubular capillary
network.
(C) the filtrate in the proximal convoluted tubule.
(D) the filtrate in the loop of Henle.
(E) the filtrate in the medullary collecting
tubule.

Answer 6

D. The countercurrent multiplier system in the loop of Henle involves ion and water exchanges between the filtrate and the interstitium. It establishes an osmotic gradient in the interstitium of the medulla, which is greatest at the papilla (see Chapter 18 V B).

Question 7

As the glomerular filtrate passes through the uriniferous tubule, ions and water are exchanged (actively or passively) with the renal interstitium, resulting in the filtrate being isotonic, hypotonic, or hypertonic relative to blood plasma. During a condition of antidiuresis, which part of the uriniferous tubule would contain a hypertonic filtrate?
(A) Ascending thick limb of the loop of Henle
(B) Bowman (capsular) space
(C) Cortical collecting tubule
(D) Medullary collecting tubule
(E) Proximal convoluted tubule

Answer 7

D. The filtrate that enters the cortical collecting tubules is nearly isotonic. When antidiuretic hormone is present (antidiuresis), water is removed from the filtrate in the collect­ ing tubules, making the filtrate hypertonic by the time it reaches the medullary collecting tubules (see Chapter 18 V C).

Question 8

As the glomerular filtrate passes through the uriniferous tubule, ions and water are exchanged (actively or passively) with the renal interstitium, resulting in the filtrate being isotonic, hypotonic, or hypertonic relative to blood plasma. During a condition of antidiuresis, which part of the uriniferous tubule would contain an isotonic filtrate?
(A) Ascending thick limb of the loop of Henle
(B) Bottom of the descending thin limb of loop of Henle
(C) Bowman (capsular) space
(D) Medullary collecting tubule
(E) Papillary collecting tubule

Answer 8

C. Filtration of blood in the renal corpuscle yields an isotonic ultrafiltrate that enters the Bowman (capsular) space (see Chapter 18 V B).

Question 9

As the glomerular filtrate passes through the uriniferous tubule, ions and water are exchanged (actively or passively) with the renal interstitium, resulting in the filtrate being isotonic, hypotonic, or hypertonic relative to blood plasma. During a condition of antidiuresis, which one of the following parts of the uriniferous tubule would contain a hypotonic filtrate?
(A) Bowman (capsular) space
(B) Cortical collecting tubule
(C) Distal portion of the ascending thick limb
of the loop of Henle
(D) Medullary collecting tubule
(E) Proximal convoluted tubule

Answer 9

C. The ascending thick limb of the loop of Henle is impermeable to water even in the presence of ADH, but it actively transports Cl from the filtrate into the interstitium (Na+ follows pas­ sively). As a result, the filtrate becomes hypotonic as it approaches the distal convoluted tubule (see Chapter 18 V B).

Question 10

As the glomerular filtrate passes through the uriniferous tubule, ions and water are exchanged (actively or passively) with the renal interstitium, resulting in the filtrate being isotonic, hypotonic, or hypertonic relative to blood plasma. During a condition of antidiure­ sis, which part of the uriniferous tubule would contain a hypertonic filtrate?
(A) Bottom of descending thin limb of Henle
(B) Bowman (capsular) space
(C) Distal portion of the ascending thick limb
(D) Pars recta of the proximal tubule
(E) Proximal convoluted tubule

Answer 10

A. The filtrate remains isotonic from the Bowman space throughout the proximal tubule, in­ cluding the pars recta (also called the thick descending limb of the loop of Henle). As it passes through the descending thin limb of the loop of Henle, the filtrate loses water to the interstitium and gains Na+ and Cl-, becoming hypertonic (see Chapter 18 V B).