The digestive system

Question 1

why does digestion occur?

Answer 1

carbohydrates, fats and protein are insoluble, they are broken down through digestion so they can be absorbed into the bloodstream

Question 2

how does chewing help break down food?

what is the function of the salivary glands?

Answer 2

• chewing is a form of physical breakdown
• saliva is released by salivary glands which contains salivary amylase and helps break down carbohydrates, saliva also keeps the oesophageas lubricated

Question 3

what is the function of the oesophagus

Answer 3

it transports chewed up food to the stomach

Question 4

what is muscular tissue? give an example
what is glandular tissue? give an example
what is epithelial tissue? give an example

Answer 4

muscular tissue contracts to bring about movement eg allows reactants to pass through the digestive system

glandular tissue produces substances like enzymes and hormones eg producing digestive juices

epithelial tissue covers most parts of the body eg lines the stomach

Question 5

what are the 3 functions of the stomach

Answer 5

1. its muscular walls contract to grind food
2. produces pepsin which is a protease enzyme that breaks down proteins
3. produces hydrochloric acid which kills bacteria and provides a good environment for pepsin to work

Question 6

what is the function of the duodenum

Answer 6

first and shortest segment of the small intestine, it receives partially digested food from the stomach

Question 7

what is the function of the pancreas?

Answer 7

secretes enzymes (pancreatic juices) into the small intestine

Question 8

what is the function of the liver

Answer 8

produces bile

Question 9

what is the function of the gallbladder

Answer 9

it stores bile

Question 10

what are the 2 functions of bile

Answer 10

1. neutralises acid from the stomach, to create a better environment for the enzymes to function
2. emulsifies fats, breaks down large drops into smaller ones to increase the surface area the lipase enzymes can act upon

Question 11

what happens after food is digested in the small intestine?

Answer 11

its absorbed into the bloodstream

Question 12

in what 3 ways is the small intestine adapted to its function

Answer 12

1. contains villi which increase surface area increasing rate of diffusion
2. one cell thick means there’s a short diffusion pathway
3. good blood supply

Question 13

undigested material is left in the small intestine and is watery due to the secretions from the gallbladder, pancreas and stomach

what does the large intestine do?

Answer 13

absorbs the excess water, producing feaces

Question 14

what do the rectum and anus do?

Answer 14

feaces are stored in the rectum until they’re removed through the anus where feaces leave the body

Question 15

briefly describe the order of digestion in 7 points

Answer 15

1. food is chewed and broken down by saliva
2. food travels down the oesophagus into the stomach
3. the stomach partially digests the food and passes it into the small intestine
4. the food mixes with pancreatic juices and bile in the small intestine
5. after food is digested its absorbed Ito the blood stream
6. undigested food passes into the liver where water is absorbed producing feaces
7. feaces leave through the anus