Question 1

Which of the following best describes the main function of osmoregulation in animals?

Accepted Answer

Balancing the intake and loss of water and solutes to maintain homeostasis

Question 2

A freshwater fish is placed in a tank with saltwater. What is the most likely physiological response?

Accepted Answer

It will lose water by osmosis and risk dehydration

Question 3

Which nitrogenous waste is most energetically expensive to produce but least toxic and least soluble in water?

Accepted Answer

Uric acid

Question 4

What is the primary advantage for terrestrial animals to excrete urea instead of ammonia?

Accepted Answer

Urea is less toxic and can be stored at higher concentrations, reducing water loss

Question 5

Which structure in the nephron is primarily responsible for the reabsorption of glucose, amino acids, and most water?

Accepted Answer

Proximal convoluted tubule

Question 6

Why is the hydrostatic pressure in the glomerulus significantly higher than in other capillaries in the body?

Accepted Answer

To drive the filtration of blood plasma into the nephron tubule

Question 7

Which of the following best explains why the descending limb of the loop of Henle is permeable to water but not to salts?

Accepted Answer

It contains aquaporins but lacks salt transporters

Question 8

What is the effect of antidiuretic hormone (ADH) on the collecting duct of the nephron?

Accepted Answer

It increases the number of aquaporins, resulting in concentrated urine

Question 9

Which of the following is a correct sequence for the flow of filtrate through the nephron?

Accepted Answer

Bowman's capsule → Proximal tubule → Loop of Henle → Distal tubule → Collecting duct

Question 10

A patient is given a medication that blocks aldosterone. What is the expected effect on their urine and blood pressure?

Accepted Answer

Decreased sodium reabsorption, increased urine volume, and decreased blood pressure

Question 11

Which of the following best describes the function of the contractile vacuole in freshwater protozoans like Paramecium?

Accepted Answer

It pumps excess water out to prevent the cell from bursting

Question 12

Which process in the nephron is responsible for moving substances such as drugs and toxins from the blood into the filtrate?

Accepted Answer

Secretion

Question 13

Why do marine bony fish excrete small amounts of highly concentrated urine?

Accepted Answer

They are hypoosmotic to their environment and must conserve water

Question 14

Which of the following is a function of the hormone erythropoietin produced by the kidney?

Accepted Answer

Stimulates red blood cell production in the bone marrow

Question 15

What is the main reason the inner medulla of the kidney is hyperosmotic?

Accepted Answer

High concentrations of NaCl and urea

Question 16

Which of the following best explains why the nephron tubule is lined with simple cuboidal epithelial cells with microvilli in the proximal tubule?

Accepted Answer

To increase surface area for reabsorption of nutrients and water

Question 17

Which of the following equations correctly represents the calculation of osmolarity?

Accepted Answer

$$Osmolarity = \frac{	ext{moles of solute}}{	ext{liters of solution}}$$

Question 18

Which of the following is the correct order of blood flow through the kidney?

Accepted Answer

Renal artery → Afferent arteriole → Glomerulus → Efferent arteriole → Peritubular capillaries → Renal vein

Question 19

A person consumes a large amount of alcohol, which acts as a diuretic. What is the expected effect on their urine output and why?

Accepted Answer

Increased urine output due to inhibition of ADH

Osmoregulation and Excretion: Mechanisms and Structures in Animals

Study Guide - Practice Questions