Question 1

Which molecule is secreted from the peritubular capillary network into the convoluted tubules? A) water B) salt C) H⁺ D) nutrients E) plasma proteins

Accepted Answer

H⁺ is actively secreted from the peritubular capillary network into the convoluted tubules.

Question 2

Why does glucose appear in the urine of a diabetic?
A) The volume of urine is too great to filter.
B) No glucose is filtered into the glomerular filtrate.
C) The kidneys produce glucose in diabetes.
D) The carriers for glucose reabsorption reach their maximum rate of transport.
E) The ascending limb of the loop of Henle secretes glucose into the urine.

Accepted Answer

In diabetes, the carriers for glucose reabsorption in the kidney reach their maximum rate of transport, resulting in excess glucose remaining in the urine and being excreted. This is known as glycosuria. Normally, almost all filtered glucose is reabsorbed back into the bloodstream through the renal tubules, but in diabetes, the high blood glucose levels overwhelm the capacity of the carriers responsible for glucose reabsorption.

Question 3

Tubular reabsorption requires both passive and active modes of reabsorption.

Accepted Answer

Tubular reabsorption refers to the process of reclaiming the useful substances from the filtrate and returning them to the blood within the peritubular capillaries. This process requires both passive and active modes of reabsorption. Passive reabsorption occurs when substances move down their concentration gradients from the tubular lumen into the interstitial fluid and then into the peritubular capillaries without requiring energy input. Active reabsorption, on the other hand, occurs when substances move against their concentration gradients from the tubular lumen into the interstitial fluid with the help of transporters that require energy input, such as ATP.

Question 4

Why do water and small molecules move from the glomerulus into the filtrate?
A) diffusion down the concentration gradient
B) glomerular blood pressure
C) active transport
D) secretion
E) diffusion against the concentration gradient

Accepted Answer

Water and small molecules move from the glomerulus into the filtrate due to glomerular blood pressure. This is because the glomerulus is a high-pressure capillary bed, which forces water and small molecules through the filtration slits in the Bowman's capsule and into the nephron.

Question 5

Which of the following particles are not filtered out of the blood in the glomerulus?
A) plasma proteins
B) water
C) nitrogenous wastes
D) salts
E) nutrients

Accepted Answer

The size and charge of plasma proteins prevent them from being filtered out of the blood in the glomerulus. The other options (water, nitrogenous wastes, salts, and nutrients) are small enough to pass through the filtration membrane in the glomerulus.

Question 6

The reabsorption of water in the kidneys always precedes the reabsorption of salt.

Accepted Answer

The reabsorption of salt in the kidneys always precedes the reabsorption of water.

Question 7

Approximately 99% of the water that is filtered in the glomerulus is reabsorbed.

Accepted Answer

Approximately 180 liters of water are filtered per day and only 1.8 liters are excreted.

Question 8

Less than 50% of which molecule is reabsorbed during tubular reabsorption?
A) urea
B) water
C) sodium
D) glucose
E) amino acids

Accepted Answer

Urea is only partially reabsorbed, with less than 50% being reabsorbed in the nephrons of the kidneys. The other molecules listed, including water, sodium, glucose, and amino acids, are reabsorbed to a much greater extent.

Question 9

While glucose is filtered out at the glomerulus, none is excreted in the urine. What happens to the glucose?
A) It is reabsorbed at the distal convoluted tubule.
B) It is secreted at the proximal convoluted tubule.
C) It is reabsorbed at the proximal convoluted tubule.
D) It is secreted at the distal convoluted tubule.
E) It is reabsorbed from the collecting duct.

Accepted Answer

Glucose is reabsorbed at the proximal convoluted tubule. The glomerulus initially filters out glucose, but it is then reabsorbed by transport proteins in the proximal convoluted tubule and returned to the bloodstream. Only when blood glucose levels exceed the reabsorptive capacity of the nephron will glucose be excreted in the urine, a condition known as glucosuria.

Question 10

What are the two ways substances are removed from the blood and added to the forming urine?
A) glomerular filtration and tubular secretion
B) glomerular filtration and tubular reabsorption
C) tubular secretion and tubular reabsorption
D) glomerular secretion and tubular reabsorption
E) glomerular secretion and tubular secretion

Accepted Answer

Substances are removed from the blood and added to the forming urine through two processes: glomerular filtration and tubular secretion. Glomerular filtration occurs in the renal corpuscle where blood is filtered through the glomerulus and filtered fluid, called filtrate, enters the renal tubules. Tubular secretion occurs in the renal tubules where substances not filtered by the glomerulus are actively secreted from the blood into the tubules to be added to the forming urine. Tubular reabsorption is the process where substances are reabsorbed from the tubules back into the blood.

Question 11

A nephron is a two-way system with glomerular filtrate traveling back and forth within the nephron.

Accepted Answer

The nephron is a one-way system. Filtrate moves from the glomerular capsule through the proximal convoluted tubule to the loop of Henle to the collecting duct.

Question 12

Which of the following does not assist the kidneys in excretion of nitrogenous wastes?
A) liver
B) sweat glands
C) muscles
D) blood
E) pancreas

Accepted Answer

The liver produces urea and muscles make creatinine. The blood carries these to the kidneys where they are eliminated. Sometimes, urea is excreted by the sweat glands in perspiration.

Question 13

Parts of the nephron are lined with epithelial cells containing large numbers of mitochondria to assist in diffusion.

Accepted Answer

Diffusion is a passive process and does not require energy. The mitochondria assist in active transport.

Question 14

Substances that are nonfilterable in the glomerulus exit the nephron through the afferent arteriole.

Accepted Answer

Substances that are nonfilterable in the glomerulus exit the nephron through the efferent arteriole, not the afferent arteriole.

Question 15

List the three processes involved in the formation of urine in order. 1. tubular secretion
2) tubular reabsorption
3) glomerular filtration
A) 1, 2, 3
B) 3, 2, 1
C) 1, 3, 2
D) 2, 3, 1
E) 2, 1, 3

Accepted Answer

Glomerular filtration is the first process as it involves the filtration of blood in the glomerulus. Tubular reabsorption follows as substances from the filtrate are selectively reabsorbed into the bloodstream. Finally, tubular secretion occurs where additional substances are added to the filtrate from the bloodstream. The correct order of the processes involved in the formation of urine is thus 3, 2, 1.

Question 16

Which part of the nephron contains podocytes?
A) distal convoluted tubule
B) proximal convoluted tubule
C) ascending limb of loop
D) descending limb of loop
E) glomerular capsule

Accepted Answer

Podocytes are specialized cells in the glomerular capsule that help form the filtration barrier in the renal corpuscle.

Question 17

Place the parts of the nephron in order of how filtration would occur. 1. ascending limb of loop 2. descending limb of loop 3. proximal convoluted tubule 4. glomerulus 5. collecting duct 6. distal convoluted tubule
A) 4, 3, 2, 1, 6, 5
B) 1, 2, 3, 4, 5, 6
C) 2, 1, 6, 4, 3, 5
D) 1, 2, 4, 3, 6, 5
E) 6, 4, 1, 2, 3, 5

Accepted Answer

Filtration in the nephron begins at the glomerulus, then moves to the proximal convoluted tubule, descending limb, ascending limb, distal convoluted tubule, and finally the collecting duct.

Question 18

How is penicillin removed from the blood?
A) glomerular filtration
B) tubular secretion
C) tubular reabsorption
D) phagocytosis
E) passive transport

Accepted Answer

Penicillin is primarily removed from the blood via tubular secretion in the kidneys. The drug is actively transported from the bloodstream into the renal tubules where it can be excreted in the urine.

Question 19

In the analogy where the liver is like the sewage treatment plant, the kidneys are like
A) the trucks that take the waste out of town.
B) the people who produce the waste.
C) trash cans where the waste is stored.
D) the trucks that carry the waste from the people who produce it to the treatment plant.
E) trucks that produce the waste.

Accepted Answer

The kidneys take the already prepared waste away from the body.

Question 20

The kidneys interact with every other organ system of the human body in maintaining homeostasis.

Accepted Answer

The kidneys play a crucial role in regulating fluid balance, electrolyte balance, acid-base balance, and blood pressure, which affects every other organ system in the body. They also help remove waste and toxins from the body, which is important for overall health and functioning. Therefore, the kidneys interact with every other organ system of the human body in maintaining homeostasis.

Quiz 11: Urinary System

Which molecule is secreted from the peritubular capillary network into the convoluted tubules?

Why does glucose appear in the urine of a diabetic?

Tubular reabsorption requires both passive and active modes of reabsorption.

Why do water and small molecules move from the glomerulus into the filtrate?

Which of the following particles are not filtered out of the blood in the glomerulus?

The reabsorption of water in the kidneys always precedes the reabsorption of salt.

Approximately 99% of the water that is filtered in the glomerulus is reabsorbed.

Less than 50% of which molecule is reabsorbed during tubular reabsorption?

While glucose is filtered out at the glomerulus, none is excreted in the urine. What happens to the glucose?

What are the two ways substances are removed from the blood and added to the forming urine?

A nephron is a two-way system with glomerular filtrate traveling back and forth within the nephron.

Which of the following does not assist the kidneys in excretion of nitrogenous wastes?

Parts of the nephron are lined with epithelial cells containing large numbers of mitochondria to assist in diffusion.

Substances that are nonfilterable in the glomerulus exit the nephron through the afferent arteriole.

List the three processes involved in the formation of urine in order. 1. tubular secretion 2) tubular reabsorption 3) glomerular filtration

Which part of the nephron contains podocytes?

Place the parts of the nephron in order of how filtration would occur. 1. ascending limb of loop 2. descending limb of loop 3. proximal convoluted tubule 4. glomerulus 5. collecting duct 6. distal convoluted tubule

How is penicillin removed from the blood?

In the analogy where the liver is like the sewage treatment plant, the kidneys are like

The kidneys interact with every other organ system of the human body in maintaining homeostasis.