B6.3 Digestion

Question 1

Identify the types of human teeth

Answer 1

(incisors, canines, premolars and molars)

Question 2

Describe the structure of human teeth

Answer 2

enamel, dentine, pulp cavity, nerves, and cement, as well as the gums

Question 3

Describe the functions of the types of human teeth in mechanical digestion of food

Answer 3

The teeth chew food which then makes it easier to swallow. The surface area of food is increased and can help the enzymes to catalyze the reactions needed for chemical digestion.

Question 4

Describe the proper care of teeth in terms of diet and regular brushing

Answer 4

Avoid sugary food and drinks between meals
clean your teeth at least twice a day
replace your toothbrush every 4 months
visit the dentist regularly every 6 months

Question 5

State the significance of chemical digestion in the alimentary canal in producing small, soluble molecules that can be absorbed

Answer 5

learn

Question 6

amylase breaks down starch to

Answer 6

sugars

Question 7

protease breaks down protein

Answer 7

acids

Question 8

lipase breaks down fats to fatty acids and

Answer 8

glycerol

Question 9

State where, in the alimentary canal where amylase is made

Answer 9

salivary gland

Question 10

State where, in the alimentary canal where protease are secreted

Answer 10

pancreas to small intestine

Question 11

State where, in the alimentary canal where lipase are secreted

Answer 11

pancreas

Question 12

State the functions of the hydrochloric acid in gastric juice,

Answer 12

killing bacteria in food and giving an acid pH for enzymes

Question 13

Explain the functions of the hydrochloric acid in gastric juice, limited to the low pH:

Answer 13

–– denaturing enzymes in harmful microorganisms in food

–– giving the optimum pH for protease activity

Question 14

What is the role of the bile in neutralising

Answer 14

in neutralizing the acidic mixture of food and gastric juices entering the duodenum from the stomach, to provide a suitable pH for enzyme action

Question 15

What is the role of the bile in emulsifying

Answer 15

emulsifying fats to increase the surface area for the chemical digestion of fat to fatty acids and glycerol by lipase

Question 16

Explain the significance of villi in increasing the internal surface area of the small intestine

Answer 16

They have a large surface area so there will be more efficient absorption of fatty acids and glycerol into the blood stream.

Question 17

Describe the structure of a villus

Answer 17

Thin epithelium on the outside, lacteal (absorbs fatty acids and glycerol, blood capilary(absorbs glucose and amino acids)

Question 18

State the causes of dental decay

Answer 18

Tooth decay occurs when foods containing carbohydrates become trapped between teeth and are not completely removed with brushing and flossing, the bacteria respiring sugars in the food, producing acid which dissolves the enamel and dentine