2.6 Role of the Kidney in Homeostasis

Question 1

What do the kidneys regulate

Answer 1

The water content of the blood and therefore the body’s cells

Question 2

What do differences in water content of cells affect

Answer 2

Concentration therefore Rate of reaction in cells

Question 3

Another thing the kidneys do

Answer 3

Remove water soluble waste products in urine

Question 4

What does urine contain

Answer 4

Urea (poisonous), excess salts, some water

Question 5

ureter

Answer 5

kidney to bladder

Question 6

urethra

Answer 6

bladder out

Question 7

What does the presence of blood or cells in the urine indicate

Answer 7

Kidney disease

Question 8

What does the presence of glucose in the urine indicate

Answer 8

Diabetes (body trying to get rid of excess glucose)

Question 9

Renal vein and vena cava carry….

Answer 9

filtered blood

Question 10

renal artery and aorta carry….

Answer 10

unfiltered blood

Question 11

cortex

Answer 11

outer

Question 12

medulla

Answer 12

middle

Question 13

pelvis

Answer 13

centre

Question 14

Describe ultrafiltration

Answer 14

The arteriole in to capillary knot is wider than the arteriole away, so pressure builds up in the capillary knot. This pressure forces out the small molecules - urea, salts, water, glucose, into the bowmans capsule and into the tubule

Question 15

Describe selective reabsorption

Answer 15

As the filtrate passes through the tubule, all of the glucose, some of the salt and most of the water is taken back into the blood
Anything not reabsorbed is excreted as urine

Question 16

What happens when there is too much water in the blood

Answer 16

Less water is reabsorbed, and the urine is pale and dilute

Question 17

What happens if there is a shortage of water in the blood/high blood concentration?

Answer 17

More water is reabsorbed, and the urine is darker and more concentrated

Question 18

Which hormone controls the amount of water reabsorbed into the blood
Produced by which gland

Answer 18

Anti diuretic hormone
Pituary gland

Question 19

What does ADH cause the kidneys to do

Answer 19

Re-absorb more water

Question 20

When blood concentration returns to normal level, what happens?

Answer 20

ADH production stops, and less water is reabsorbed

Question 21

If blood concentration is too high, what happens?

Answer 21

ADH is produced by the pituary gland

Question 22

What does a kidney dialysis machine do?

Answer 22

Removes waste and restores the balance of salts and water in the blood

Question 23

What is the dialysate?

Answer 23

A dialysis fluid containing salts

Question 24

How are the dialysate and blood separated?

Answer 24

By a selectively permeable membrane

Question 25

How do salts move out of the blood in dialysis

Answer 25

They diffuse out down the concentration gradient

Question 26

How does water move out of the blood in dialysis?

Answer 26

It moves out by osmosis

Question 27

Problems with kidney dialysis

Answer 27

3 to 4 hour sessions on the machine a week this is inconvenient Patients must restrict fluid and salt intake, so dangerous levels aren’t reached

Question 28

Advantage of kidney transplantation

Answer 28

Patients don’t have to undergo kidney dialysis

Question 29

Disadvantages of kidney transplantation

Answer 29

Involves surgery, carries some risk Patients must take immunosuppressive drugs to avoid transplant rejection, this increases the chance of infections Transplanted kidneys have limited lifespan so multiple may be needed Patient must be healthy and strong A person must only receive a kidney from someone with a similar tissue-type some patients wait years for a donor