Excretory Systems

Question 1

What are the main functions of excretory systems?

Answer 1

Remove metabolic waste, regulate ion balance, osmolarity, and fluid volume.

Question 2

What nitrogenous waste forms do animals excrete?

Answer 2

Ammonia (toxic, aquatic animals), urea (less toxic, mammals), uric acid (least toxic, birds/reptiles).

Question 3

What are examples of extrarenal excretory structures?

Answer 3

Gills (excrete ammonia), salt glands (excrete salt in marine birds/reptiles).

Question 4

What is the structure of a nephron?

Answer 4

Renal corpuscle (glomerulus + Bowman’s capsule), proximal tubule, loop of Henle, distal tubule, collecting duct.

Question 5

What are the four main processes of renal excretion in a nephron?

Answer 5

Filtration, reabsorption, secretion, and excretion.

Question 6

What does vasopressin (ADH) do?

Answer 6

Increases water reabsorption in the collecting duct to conserve water.

Question 7

What does aldosterone do?

Answer 7

Increases Na+ reabsorption and K+ secretion, helping retain water and increase blood pressure.

Question 8

What does ANP (atrial natriuretic peptide) do?

Answer 8

Increases Na+ and water excretion to lower blood volume and pressure.

Question 9

What is the RAAS system?

Answer 9

A hormone system that raises blood pressure by increasing water and Na+ retention and causing vasoconstriction.