Excretory System

Question 1

What are the waste products from the excretory system in order from most to least toxic?

Answer 1

Ammonia
Urea
Uric acid

Question 2

What are the steps of urine formation?

Answer 2

Filtration: water, nutrients, and wastes are filtered from glomerular capillaries into Bowman’s capsule of the nephron

Tubular Reabsorption: in the proximal tubule, most water and nutrients are reabsorbed into the blood

Tubular Secretion: in the distal tubule, additional wastes are actively secreted into the tubule from the blood

Concentration: in the collecting duct, additional water may leave the blood, creating irons that is more concentrated then blood

Question 3

Describe the process of filtration.

Answer 3

High pressure
Movement of materials from high pressure to low pressure
Things that are filtered out of the blood into the tubule: water, salts, glucose, amino acids, urea, hydrogen ions
Things that stay in the blood: plasma proteins, erythrocytes, platelets

Question 4

Describe the process of reabsorption.

Answer 4

Movement of materials out of the tubule back into blood
Solutes pumped out (active Transport) create osmotic gradient that moves water out of tubule into blood
Threshold level: max amount of solutes and water that can be in the blood

Question 5

Describe the process of secretion?

Answer 5

Wastes out of blood and into the tubule (ammonia, hydrogen, minerals)
Active transport
In the distal tubule

Question 6

What is Anti-Diuretic Hormone?

Answer 6

Makes the collecting duct more permeable to water

Smaller amounts of more concentrated urine

Question 7

What is Aldosterone?

Answer 7

Increase the amount of Na in the blood and creates osmotic pressure so water reabsorption increases too

Happens in the proximal tubule and loop of henle

Question 8

Urea levels will become less concentrated if a person decreases their consumption of:

Answer 8

Protein