Unit 6- 3.6.4.3 Control of blood water potential

Question 1

Which 2 parts of the nephron are involved in ultrafiltration?

Answer 1

Glomerulus and Renal Capsule

Question 2

Which branch of the renal artery supplies the glomerulus with blood?

Answer 2

Afferent arteriole

Question 3

Which filtration layer filters the large plasma proteins?

Answer 3

Basement membrane

Question 4

Which 2 substances are completely reabsorbed in the PCT?

Answer 4

Glucose and amino acids

Question 5

Name 3 adaptations of the cells of the PCT.

Answer 5

1. Microvilli
2. Numerous mitochondria
3. Numerous carrier proteins

Question 6

Which part of the loop of Henle is impermeable to water?

Answer 6

Ascending limb

Question 7

By which process are the sodium and chloride ions removed from the ascending limb of the loop of Henle?

Answer 7

Active transport

Question 8

In the loop of Henle, where does the filtrate have the highest concentration?

Answer 8

At the base

Question 9

ADH gets released from which gland?

Answer 9

Pituitary gland

Question 10

ADH binds to receptors on which 2 parts of the nephron?

Answer 10

DCT and collecting duct

Question 11

What does ADH cause to happen when it binds to receptors?

Answer 11

Stimulates aquaporins to move to the cell surface membrane. So more water is reabsorbed from the filtrate by osmosis.

Question 12

Which receptors are sensitive to changes in water potential ?

Answer 12

Osmoreceptors

Question 13

When the water potential of the blood is low, what happens to the amount of ADH released?

Answer 13

More ADH released

Question 14

When the water potential of the blood is low, what happens to the permeability of the CD and DCT?

Answer 14

Permeability increases

Question 15

Describe the urine produced when the water potential of the blood is high?

Answer 15

Larger volume and more dilute.

Question 16

Alcohol decreases the release of ADH into the blood. Suggest two signs or symptoms which may result from a decrease in ADH.

Answer 16

1. Increase in volume of urine
2. Dilute urine

Question 17

Give the location of osmoreceptors in the body of a mammal.

Answer 17

Hypothalamus

Question 18

Some desert mammals secrete large amounts of antidiuretic hormone (ADH). Explain how this feature is an adaptation to living in desert conditions. (2 marks)

Answer 18

Makes cells of DCT and CD more permeable;
So more water can be reabsorbed by osmosis;