Digestive System

Question 1

What is the function of the digestive system?

Answer 1

To break down food so nutrients can be absorbed into the bloodstream and then transported to cells.

Question 2

What do enzymes do?

Answer 2

Speed up reactions. They break up molecules in food so the nutrients are small enough to be absorbed by diffusion.

Question 3

What’s the difference between chemical and mechanical digestion?

Answer 3

• Chemical is digestion on a molecular level.
• Mechanical is physical digestion that involves movement.

Question 4

What are the 9 organs involved in the digestive system?

Answer 4

1. Mouth
2. Oesophagus
3. Stomach
4. Pancreas
5. Liver
6. Small intestine
7. Large intestine
8. Rectum
9. Anus

Question 5

In what ways does digestion happen in the mouth? (3 things)

Answer 5

1. Chewing increases surface area of food and makes a bolus.
2. Tongue shapes the bolus.
3. Saliva contains the amylase enzyme which breaks down carbs.

Question 6

What is the role of the oesophagus?

Answer 6

To push bolus down into the stomach using peristalsis.

Question 7

In what ways does digestion happen in the stomach? (2 things)

Answer 7

1. Mechanical churning breaks chyme down.
2. Bile, enzymes, and bacteria chemically break chyme down to its molecules.

Question 8

In what ways does digestion happen in the small intestine? (3 things)

Answer 8

1. Nutrients are absorbed by the villi into the bloodstream using diffusion.
2. Bacteria aids digestion.
3. Digestive juices and enzymes break down carbs, fats, and proteins.

Question 9

What is the role of the pancreas? (3 things)

Answer 9

1. To make digestive enzymes
2. To neutralise stomach acid
3. Both are released into the small intestine.

Question 10

What is the role of the liver? (2 things)

Answer 10

1. Makes bile. Extra bile is stored in the gallbladder.
2. Bile helps the digestion of lipids (fats) by breaking them down into smaller pieces so the lipase enzyme can digest it.

Question 11

In what ways does digestion happen in the large intestine? (3 things)

Answer 11

1. Water is reabsorbed into the bloodstream.
2. Vitamins are absorbed.
3. Waste products are formed.

Question 12

What is the role of the rectum? (2 things)

Answer 12

1. To store faeces.
2. To send messages to the brain that the waste is ready to be excreted.

Question 13

What is the role of the anus? (2 things)

Answer 13

To relax muscles to allow faeces to be removed.

Question 14

What are three enzymes and what do they work on?

Answer 14

1. Amylase - carbohydrates
2. Protease - protein
3. Lipase - lipids (fats)

Question 15

What are 3 adaptations of the small intestine?

Answer 15

1. Villi have large surface area to maximise diffusion of nutrients into bloodstream
2. Villi have thin walls (1 cell thick) for efficient diffusion
3. Villi in close proximity to blood vessels for easy and quick diffusion.