Kidneys

Question 1

What do the kidneys do

Answer 1

Make urine by taking waste products from the blood

Substances are filtered out of the blood as it passes through the kidneys this is called filtration

Selective reabsorption occurs if there are any useful substances still located in the water

Question 2

If the water content is to high then…

Answer 2

The brains receptors detect this and the coordination centre in the brain receives this information and coordinates a response. The pituitary gland releases less ADH so less water is reabsorbed as the walls of the kidney tubules become less permeable

Question 3

If the water content is to low then

Answer 3

A receptor in the brain detects that the water content is too low
The coordination centre of the brain receives the information and coordinates a response . The pituitary gland releases more ADH so more water is reabsorbed from the kidney tubules as the walls of the tubules become more permeable

Question 4

What happens when the kidneys do not function correctly

Answer 4

Waste substances build up in the blood and you lose the ability to control levels of ions and water in the body

Question 5

Dialysis treatment

Answer 5

The persons blood flows through between partially permeable membranes surrounded by dialysis fluids . These membranes allow ions and waste substances through but not larger molecules like proteins .

The dialysis has the same concentration as healthy blood and will not dissolve useful ions . Only waste substances diffuse across the barrier

However the process is not pleasant and is expensive for the NHS however it can give these people time before they are at the top of the waiting lists