Digestive system Flashcards
1
Q
Why do humans eat a lot of food
A
- To have energy to move and for metabolism
2
Q
What is the purpose of digestion
A
- To break big molecules of food down into smaler, absorbable molecules
3
Q
What is the role of the mouth in the digestive system
A
- Mechanically breaks down food molecules by churning and teeth
- Produces saliva which contains the enxyme amylase which breaks starch down into glucose
4
Q
What is the role of the oesophagus in the digestive system
A
- Transport food molecules from the mouth to the stomach
5
Q
What is the role of the stomach in the digestive system
A
- Food is mechanically broken down as the muscular walls of the stomach contract
- Proteins are broken down by the enzyme pepsin into amino acids
- The stomach acid (pH 2) provides the optimum pH for pepsin to breakdown proteins
6
Q
What is the role of the small intestine in the digestive system
A
- Food molecules are absorbed into the bloodstream
- Bile (produced in the liver and stored in the gall bladder) emulsifies fats and neutralises the pH of the stomach acid
- Enzymes are passed into the small intestine by pancreatic juices
7
Q
What are the adaptations of the villi of the small intestine
A
- Lots of villi - increases the overall surface area of the small intestine and therefore the rate of diffusion
- Rich blood supply - maintain a strong concentration gradient
- One cell thick walls - small diffusion distance
8
Q
What is the role of the large intestine in the digestive system
A
- Absorbs excess water from food molecules that were not absorbed in the small intestine
9
Q
What is the role of the rectum in the digestive system
A
- Stores faeces until excreted
