BIOL 252 | BIOL252 Module 6: Human Anatomy &
Physiology II with Lab Updated and Latest
Questions and Correct Answers with Rationale -
Portage Learning
1. Where are the kidneys located within the abdominal cavity?
A. Intraperitoneal space
B. Thoracic cavity
C. Pelvic cavity
D. Retroperitoneal space
Correct Answer: D
Explanation: The kidneys are located in the retroperitoneal space between the T12 and L3
vertebrae. This positioning means they are situated behind the parietal peritoneum against
the posterior abdominal wall. The right kidney is slightly lower than the left to
accommodate the liver. Protection is provided by the rib cage and layers of fat and
connective tissue. Understanding this anatomy is crucial for surgical approaches and
diagnosing flank pain.
2. Which structure is considered the functional unit of the kidney?
A. Renal pelvis
B. Major calyx
C. Nephron
D. Ureter
Correct Answer: C
Explanation: The nephron is the structural and functional unit responsible for filtering
blood and forming urine. Each kidney contains approximately one million nephrons which
process blood plasma. It consists of a renal corpuscle and a renal tubule system. The renal
pelvis and calyces are simply collecting structures for urine already formed. Nephrons
perform the critical tasks of filtration, reabsorption, and secretion.
3. What is the primary function of the proximal convoluted tubule (PCT)?
A. Concentration of urine
B. Filtration of blood cells
C. Reabsorption of majority of water and solutes
D. Storage of urine
,Correct Answer: C
Explanation: The PCT is the site where about 65 percent of water and nearly all nutrients
are reabsorbed. Its cells have numerous microvilli that create a large surface area for
transport processes. Glucose and amino acids are almost entirely reclaimed here under
normal conditions. This segment also performs significant secretion of nitrogenous wastes
and some drugs. Without the efficient reabsorption of the PCT, the body would lose vital
nutrients and fluid rapidly.
4. Which part of the nephron loop is highly permeable to water but not to solutes?
A. Thick ascending limb
B. Descending limb
C. Thin ascending limb
D. Distal convoluted tubule
Correct Answer: B
Explanation: The descending limb of the loop of Henle allows water to leave the tubule via
osmosis. It is relatively impermeable to solutes like sodium and chloride ions. As water
leaves, the filtrate inside the tubule becomes increasingly concentrated. This process is
essential for the countercurrent multiplier system that helps concentrate urine. The
ascending limb has the opposite permeability characteristics to maintain the osmotic
gradient.
5. Which hormone is released by the posterior pituitary to increase water reabsorption?
A. Aldosterone
B. Atrial natriuretic peptide
C. Antidiuretic hormone
D. Renin
Correct Answer: C
Explanation: Antidiuretic hormone, or ADH, acts on the collecting ducts to increase water
permeability. It triggers the insertion of aquaporins into the cell membranes to facilitate
water recovery. When ADH levels are high, the body produces a small volume of
concentrated urine. Conversely, low ADH leads to the production of large volumes of dilute
urine. This hormone is a key player in maintaining blood pressure and fluid balance.
6. What pressure is the primary driver of glomerular filtration?
A. Capsular hydrostatic pressure
B. Blood colloid osmotic pressure
C. Glomerular hydrostatic pressure
, D. Intra-abdominal pressure
Correct Answer: C
Explanation: Glomerular hydrostatic pressure is the blood pressure within the glomerular
capillaries themselves. It pushes water and solutes across the filtration membrane into the
capsular space. This pressure is typically higher than in other capillaries due to the
different diameters of arterioles. Capsular hydrostatic and blood colloid osmotic pressures
act as opposing forces to filtration. The net filtration pressure is the sum of these
competing physical forces.
7. Which cells in the juxtaglomerular apparatus act as mechanoreceptors to sense blood
pressure?
A. Macula densa cells
B. Mesangial cells
C. Podocytes
D. Granular cells
Correct Answer: D
Explanation: Granular cells, also known as juxtaglomerular cells, are modified smooth
muscle cells in the afferent arteriole. They act as mechanoreceptors that detect changes in
the stretch of the vessel wall. When blood pressure drops, these cells release the enzyme
renin into the bloodstream. Renin then initiates a cascade that ultimately raises blood
pressure and volume. Macula densa cells are different as they function as chemoreceptors
for salt concentration.
8. What effect does Atrial Natriuretic Peptide (ANP) have on the kidneys?
A. Promotes sodium and water excretion
B. Increases blood volume
C. Decreases sodium excretion
D. Stimulates renin release
Correct Answer: A
Explanation: ANP is released by the heart atria in response to high blood pressure or
volume. It acts on the kidneys to increase the excretion of sodium and water. By inhibiting
aldosterone and renin, it helps reduce overall blood volume and pressure. This hormone
provides a counterbalance to the water-retaining effects of the RAAS system. Its primary
goal is to protect the heart from being overloaded by excess fluid.
9. In the case of severe dehydration, what would happen to the GFR?
A. It would increase to flush out toxins
Physiology II with Lab Updated and Latest
Questions and Correct Answers with Rationale -
Portage Learning
1. Where are the kidneys located within the abdominal cavity?
A. Intraperitoneal space
B. Thoracic cavity
C. Pelvic cavity
D. Retroperitoneal space
Correct Answer: D
Explanation: The kidneys are located in the retroperitoneal space between the T12 and L3
vertebrae. This positioning means they are situated behind the parietal peritoneum against
the posterior abdominal wall. The right kidney is slightly lower than the left to
accommodate the liver. Protection is provided by the rib cage and layers of fat and
connective tissue. Understanding this anatomy is crucial for surgical approaches and
diagnosing flank pain.
2. Which structure is considered the functional unit of the kidney?
A. Renal pelvis
B. Major calyx
C. Nephron
D. Ureter
Correct Answer: C
Explanation: The nephron is the structural and functional unit responsible for filtering
blood and forming urine. Each kidney contains approximately one million nephrons which
process blood plasma. It consists of a renal corpuscle and a renal tubule system. The renal
pelvis and calyces are simply collecting structures for urine already formed. Nephrons
perform the critical tasks of filtration, reabsorption, and secretion.
3. What is the primary function of the proximal convoluted tubule (PCT)?
A. Concentration of urine
B. Filtration of blood cells
C. Reabsorption of majority of water and solutes
D. Storage of urine
,Correct Answer: C
Explanation: The PCT is the site where about 65 percent of water and nearly all nutrients
are reabsorbed. Its cells have numerous microvilli that create a large surface area for
transport processes. Glucose and amino acids are almost entirely reclaimed here under
normal conditions. This segment also performs significant secretion of nitrogenous wastes
and some drugs. Without the efficient reabsorption of the PCT, the body would lose vital
nutrients and fluid rapidly.
4. Which part of the nephron loop is highly permeable to water but not to solutes?
A. Thick ascending limb
B. Descending limb
C. Thin ascending limb
D. Distal convoluted tubule
Correct Answer: B
Explanation: The descending limb of the loop of Henle allows water to leave the tubule via
osmosis. It is relatively impermeable to solutes like sodium and chloride ions. As water
leaves, the filtrate inside the tubule becomes increasingly concentrated. This process is
essential for the countercurrent multiplier system that helps concentrate urine. The
ascending limb has the opposite permeability characteristics to maintain the osmotic
gradient.
5. Which hormone is released by the posterior pituitary to increase water reabsorption?
A. Aldosterone
B. Atrial natriuretic peptide
C. Antidiuretic hormone
D. Renin
Correct Answer: C
Explanation: Antidiuretic hormone, or ADH, acts on the collecting ducts to increase water
permeability. It triggers the insertion of aquaporins into the cell membranes to facilitate
water recovery. When ADH levels are high, the body produces a small volume of
concentrated urine. Conversely, low ADH leads to the production of large volumes of dilute
urine. This hormone is a key player in maintaining blood pressure and fluid balance.
6. What pressure is the primary driver of glomerular filtration?
A. Capsular hydrostatic pressure
B. Blood colloid osmotic pressure
C. Glomerular hydrostatic pressure
, D. Intra-abdominal pressure
Correct Answer: C
Explanation: Glomerular hydrostatic pressure is the blood pressure within the glomerular
capillaries themselves. It pushes water and solutes across the filtration membrane into the
capsular space. This pressure is typically higher than in other capillaries due to the
different diameters of arterioles. Capsular hydrostatic and blood colloid osmotic pressures
act as opposing forces to filtration. The net filtration pressure is the sum of these
competing physical forces.
7. Which cells in the juxtaglomerular apparatus act as mechanoreceptors to sense blood
pressure?
A. Macula densa cells
B. Mesangial cells
C. Podocytes
D. Granular cells
Correct Answer: D
Explanation: Granular cells, also known as juxtaglomerular cells, are modified smooth
muscle cells in the afferent arteriole. They act as mechanoreceptors that detect changes in
the stretch of the vessel wall. When blood pressure drops, these cells release the enzyme
renin into the bloodstream. Renin then initiates a cascade that ultimately raises blood
pressure and volume. Macula densa cells are different as they function as chemoreceptors
for salt concentration.
8. What effect does Atrial Natriuretic Peptide (ANP) have on the kidneys?
A. Promotes sodium and water excretion
B. Increases blood volume
C. Decreases sodium excretion
D. Stimulates renin release
Correct Answer: A
Explanation: ANP is released by the heart atria in response to high blood pressure or
volume. It acts on the kidneys to increase the excretion of sodium and water. By inhibiting
aldosterone and renin, it helps reduce overall blood volume and pressure. This hormone
provides a counterbalance to the water-retaining effects of the RAAS system. Its primary
goal is to protect the heart from being overloaded by excess fluid.
9. In the case of severe dehydration, what would happen to the GFR?
A. It would increase to flush out toxins
