Question 1

Which of the following is the primary function of the urinary system in mammals?

Accepted Answer

To excrete cellular wastes and help maintain homeostasis

Question 2

Which nitrogenous waste is most toxic and requires the most water for excretion?

Accepted Answer

Ammonia ($$NH_3)$$

Question 3

Birds excrete nitrogenous waste primarily as uric acid. What is a major advantage of this adaptation?

Accepted Answer

Uric acid requires almost no water to produce

Question 4

Which structure in the mammalian nephron is primarily responsible for the filtration of blood?

Accepted Answer

Glomerulus

Question 5

In which part of the nephron does the majority of water and essential nutrients get reabsorbed into the blood?

Accepted Answer

Proximal tubule

Question 6

Which hormone increases the permeability of the distal tubule and collecting duct to water, thereby concentrating urine?

Accepted Answer

Antidiuretic hormone (ADH)

Question 7

A patient is severely dehydrated. Which of the following physiological responses would you expect?

Accepted Answer

Increased permeability of the collecting duct to water

Question 8

Which of the following best describes the process of secretion in the nephron?

Accepted Answer

Active transport of wastes and excess ions from the blood into the renal tubule

Question 9

Which adaptation allows desert mammals to conserve water more efficiently than mammals in wet environments?

Accepted Answer

High percentage of nephrons with long loops of Henle

Question 10

What is the main function of the Malpighian tubules in insects?

Accepted Answer

To produce urine from hemolymph and excrete it with feces

Question 11

Which of the following is NOT a way that vertebrate urinary systems help maintain homeostasis?

Accepted Answer

Producing digestive enzymes

Question 12

A freshwater fish is placed in saltwater. Which of the following challenges will it face?

Accepted Answer

Water leaving its body by osmosis and salt entering by diffusion

Question 13

Which process in the nephron is most directly responsible for removing small molecules and ions from the blood under high pressure?

Accepted Answer

Filtration

Question 14

Which of the following would most likely occur if the hypothalamus failed to detect increased blood osmolarity?

Accepted Answer

Inability to concentrate urine during dehydration

Question 15

Which of the following is a correct sequence of urine formation in the nephron?

Accepted Answer

Filtration → Reabsorption → Secretion

Question 16

A person with malfunctioning kidneys is unable to regulate blood pH. Which process is most directly affected?

Accepted Answer

Reabsorption of $$HCO_3$$^-$$ and secretion of H$$^+$$

Question 17

Which of the following best explains why saltwater fish drink seawater?

Accepted Answer

To replace water lost by osmosis to their hypertonic environment

Question 18

Which of the following is a direct effect of the hormone angiotensin?

Accepted Answer

Stimulates aldosterone release, increasing sodium reabsorption

Question 19

Which of the following is true about the urinary systems of sponges and cnidarians?

Accepted Answer

They lack urinary systems and rely on diffusion and active transport

Question 20

A person is given a drug that blocks the action of ADH. What is the most likely effect on their urine?

Accepted Answer

Urine volume will increase and become more dilute

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Study Guide - Practice Questions