Mouth and Oesophagus

Question 1

what is the first structure in the alimentary canal?

Answer 1

the mouth

Question 2

where does ingestion take place?

Answer 2

the mouth

Question 3

what does digestion take place?

Answer 3

the mouth

Question 4

what are the two types of digestion?

Answer 4

mechanical and chemical

Question 5

mechanical digestion definition?

Answer 5

food is broken up into smaller pieces in the mouth by chewing
- this increases the surface area for enzymes and also prevents discomfort when swallowing

Question 6

chemical digestion?

Answer 6

saliva is released into the mouth by the salivary glands, it makes the food easier to swallow, and also contains the enzyme amylase, amylase breaks down the starch to maltose

Question 7

enzyme amylase when reacted with starch?

Answer 7

starch —–amylase—–> maltose

Question 8

what pH does amylase work best at?

Answer 8

neutral

Question 9

what happens when amylase reaches the stomach?

Answer 9

it denatures - the pH is too high

Question 10

how does swallowing work?

Answer 10

• before swallowing the food is shaped into a ball (a bolus) by the tongue and moved towards the back of the mouth
• there is a flap called the epiglottis which blocks the food from entering the trachea

Question 11

where does food travel down to get to the stomach?

Answer 11

the oesophagus

Question 12

how does food get pushed down the oesophagus?

Answer 12

peristalsis - wave like contractions

Question 13

where else does peristalsis occur?

Answer 13

small and large intestines

Question 14

what muscles push the food down the oesophagus?

Answer 14

• circular muscles which contract behind the bolus
• longitudinal muscles which make the oesophagus wider