Paper 2 - Osmoregulation N Dat

Question 1

What is the role of ADH (anti-diuretic hormone)?

Answer 1

ADH helps retain water, less urine produced. The more ADH released by the pituitary gland, the more permeable the collect duct in the kidneys to allow more water to be reabsorbed into the blood and out of the nephron.

Question 2

What are the three main roles of the kidney?

Answer 2

• Removal of urea from the blood. Urea is produced in the liver from the breakdown of excess amino acids.
• Adjusts level of ions in the blood
• Adjusts the water content of the blood

Question 3

How do kidneys work?

Answer 3

They filter stuff out of the blood under high pressure and then reabsorbing the useful things. The end product is urine.

Question 4

First part of the nephron : Bowman’s capsule

Answer 4

Liquid part of blood (containing water, urea, ions and glucose) is forced out of the glomerulus and into the Bowman’s capsule at high pressure (ultrafiltration).

Question 5

Second part of the nephron: Loop of Henle

Answer 5

Liquid flows along the nephron, useful substances are reabsorbed. ALL glucose is reabsorbed selectively, sufficient ions and water are also reabsorbed according to the ADH level.

Question 6

Third part of the nephron: Collecting duct

Answer 6

Whatever isn’t reabsorbed continues out of the nephron via the collecting duct passing into the ureter down to the bladder as urine. Urine is released through the urethra.

Question 7

How do animals adapt their loop of Henle?

Answer 7

Animals living in drought/dry conditions have longer loops of Henle to reabsorb more water.