Kidney function

Question 1

What are nephrons?

Answer 1

Filtration units in the kidneys.

Question 2

What are nephrons in charge of?

Answer 2

• Ultrafiltration.
• Reabsorption.
• Release of waste.

Question 3

How does ultrafiltration work?

Answer 3

• A high pressure is built up which squeezes water, urea, ions and sugar out of the blood and into the bowman’s capsule.
• The membranes between the blood vessels and the bowman’s capsule act like filters, so big molecules like proteins and blood cells are not squeezed out, they stay in the blood.

Question 4

What happens as the liquid flows along the nephron?

Answer 4

Useful substances are reabsorbed back into the blood.

Question 5

What substances are reabsorbed back into the blood?

Answer 5

• All the sugar is reabsorbed.
• Sufficient ions are reabsorbed, excess ions are not.
• Sufficient water is reabsorbed.

Question 6

When is active transport required?

Answer 6

During the reabsorption of Sugar and sufficient ions.

Question 7

What process is required during the reabsorption of some substances?

Answer 7

Active transport.

Question 8

What happens to the remaining substances after ultrafiltration and reabsorption?

Answer 8

The remaining substances (including urea) continue out of the nephron, into the ureter and down to the bladder as urine.