B3.3.3

Question 1

What does your body have to regulate + where are they got from

Answer 1

The amount of salt and water present. Water and salts enter the body through consuming food and drink, water is also produced from respiration.

Question 2

Why is it important that water and salt levels remain constant

Answer 2

If too much water is present it will move into your blood cells, causing them to swell and burst known as lysis.
If too little water is present or there is too much solute water diffuses out of cells causing them to crenate.

Question 3

What does urine contain

Answer 3

Urine contains water, urea and other substances

Question 4

What do the kidneys do

Answer 4

The kidneys filter urea out of your blood and produce urine constantly. This is because urea is toxic. The urine is stored in the bladder which stores it until they urinate.

Question 5

What happens to the small molecules

Answer 5

Small molecules including water, glucose, urea and salts pass into tubes inside the kidney. Blood cells are too large so remain within the capillaries.

Question 6

What do the kidneys do

Answer 6

The kidneys balance the amount of water you take in with the amount you lose through breathing and sweating by altering the amount of urine produced.

Question 7

What do the kidneys do with the useful substances

Answer 7

They put useful substances back into the blood e.g glucose and salts and some water -> selective reabsorption

Question 8

What is the difference between dilute and concentrated urine

Answer 8

Lots of water consumed - dilute urine
Little amount of water consumed - concentrated urine