Movement of substances

Question 1

what is excretion

Answer 1

• the removal of toxic waste products due to chemical reactions from the body

Question 2

how is urea made

Answer 2

from the breakdown of excess amino acids (deamination) in liver cells

Question 3

where is urea removed

Answer 3

kidneys and skin

Question 4

HOW is urea formed

Answer 4

• amino acids are filtered into the liver along with the rest of the blood
• excess amino acids can’t be stored like carbohydrates and lipids can so they are broken down into carbohydrates and ammonia
• ammonia is very toxic and must be converted into a slightly less toxic chemical called urea
• the amino acids that are needed and the urea are released back into the bloodstream via the hepatic vein so that it can be removed by the kidney

Question 5

what is the role of the kidney

Answer 5

to filter the bloods and remove any excess materials so that they can be passed on to the bladder to be excreted

Question 6

what are the three main sections of the kidney

Answer 6

cortex
medulla
pelvis
(from outside to inside)