B2.1: Principles of organisation

Question 1

What is the order in which food passes through the digestive system?

Answer 1

Mouth->oesophagus-> stomach-> small intestine->large intestine->rectum->anus

Question 2

What is the function of the mouth in digestion?

Answer 2

To mechanically break up food into smaller pieces to increase surface area.

Question 3

What are two functions of saliva in digestion?

Answer 3

1.To moisten food to allow easier swallowing, 2.To start chemical digestion by containing salivary amylase.

Question 4

What is the function of stomach acid?

Answer 4

To kill potentially pathogenic microorganisms in food (NOT to digest food).

Question 5

What is the function of the small intestine?

Answer 5

To absorb carbohydrates, lipids, amino acids, vitamins and mineral ions from digested food.

Question 6

Give an adaptation of a) the small intestine and b) cells lining the small intestine to aid absorption of digested molecules.

Answer 6

a) Small intestine has structures called villi which increase surface area, b) Epithelial cells lining the villi have microvilli on their surface which further increase surface area.

Question 7

What is the function of the large intestine?

Answer 7

To absorb water from digested food.

Question 8

What is the function of the liver in digestion?

Answer 8

To produce bile, an emulsifying and neutralising substance.

Question 9

What is the function of the gall bladder?

Answer 9

To store bile until it can be released into the small intestine.

Question 10

What is the function of the rectum?

Answer 10

To store undigested material before excretion.