Homeostasis - The Kidneys

Question 1

What do kidneys do?

Answer 1

Kidneys act as filters to clean blood

Question 2

How does the kidney make urine?

Answer 2

• the kidney makes urine by taking waste products (and other unwanted substances) out of your blood
• substances are filtered out of the blood and it passes through the kidneys - process known as filtration
• useful substances like glucose, some ions and the right amount of water are then absorbed back into the blood - process known as selective reabsorption
• substances that are removed from the body in urine are: urine, ions and water

Question 3

Describe how the concentration of urine is controlled by ADH through negative feedback when water-content is too high?

Answer 3

• A receptor in the brain detects the water content is too high
• The coordination centre receives and processes the information and organises a response
• The pituitary gland releases less ADH, so less water is reabsorbed by the kidney tubules

Question 4

Describe how the concentration of urine is controlled by ADH using negative feedback when the water content is too low

Answer 4

• A receptor in the brain detects the water content is too low
• The coordination centre receives and processes the information and organises a response
• The pituitary gland releases more ADH, so more water is reabsorbed by the kidney tubules