B2 - Animal Organs Flashcards
Why is food needed?
Growth and repair
What is the digestive system responsible for?
Breaking down food into small enough particles so that it can pass into the circulatory system
What happens to the food in the mouth?
It is grinded down by the teeth
Carbohydrates are broken down into simple sugars with salivary amylase
What happens to food in the stomach?
Hydrochloric acid sterilises the food, breaks down the food further and provides the correct pH for protease to work
Protease breaks down proteins into amino acids
Why does the hydrochloric acid in the stomach need to sterilise the food?
The food is covered in microorganisms
Why do we get food poisoning?
Because the hydrochloric acid sterilisation has not worked
Why are cells in stomach replaced so often?
The acid damages the stomach cells
What happens to the food in the small intestine?
It meets bile from the liver and enzymes from the pancreas
What does bile do?
It neutralises the hydrochloric acid from the stomach
It emulsifies the fats
Why does the bile need to neutralise the acid?
The enzymes from the pancreas need a neutral pH
Which enzymes does the pancreas release into the small intestine?
Proteases (proteins to amino acids)
Lipases (lipids [fats] into fatty acids and glycerol)
Carbohydrases (carbohydrates into simple sugars)
Where do the useful nutrients go after being broken down in the small intestine?
Through the hair-like villi on the small intestine and into the bloodstream
Where does the food waste go after the small intestine?
Into the large intestine to be egested
What is cell diffrentiation?
When cells divide and become slightly different
In the long term, the cells form groups and become specialised
How many cells must there be in a developing foetus before cell differentiation can occur?
16
This is called the 16-cell stage
