Topic 5 - The Kidneys (Paper 2)

Question 1

what 3 roles do the kidneys perform?

Answer 1

1. removal of urea from the blood.
2. ajustment of ion levels in the blood
3. ajustment of water content of the blood

Question 2

what happens in the nephrons?

Answer 2

ultrafiltration, reabsorbtion and release of wastes

Question 3

what is ultrafiltration?

Answer 3

blood from the renal artery flows into the glomerulus
a high pressure is built up so water, urea, ions and glucose are squeezed out of the blood and into the bowman’s capsule
the membranes between the glomerulus and bowman’s capsule act like filters, so protiens and blood cells arent squeezed out

Question 4

what is reabsorbtion?

Answer 4

as the filtrate flows along the nephron, useful substances are selectively reabsorbed
all the glucose is reabsorbed from the proximal convoluted tubule
sufficient ions are reabsorbed
sufficient water is reabsorbed from the collecting duct

Question 5

how are wastes released?

Answer 5

substances that remain in the blood after reabsorbtion continue out of the nephron, through the ureter and down to the bladder

Question 6

how is water taken into/lost from the body?

Answer 6

water is taken in as food or drink
water is lost by sweating, breathing and urinating

Question 7

what is osmoregulation?

Answer 7

the body balancing the water coming in against the water coming out

Question 8

what is ADH?

Answer 8

the hormone that controls the amount of water reabsorbed by the kidney

Question 9

what happens if water content is low in the blood?

Answer 9

brain detects water loss
pitautry gland releases more ADH
ADH makes the kidney reabsorb more water

Question 10

what happens if water content is high in the blood?

Answer 10

brain detects water gain
pitautry gland releases less ADH
less ADH means the kidney reabsorb less water