The Alimentary Canal

Question 1

What is the alimentary canal?

Answer 1

The alimentary canal is a continous muscular tube which runs from the mouth to the anus and consists a large part of the human digestive system.

Question 2

What is the function of the mouth in digestion?

Answer 2

1. The mouth contains teeth, which break down food.

2. The mouth contains salivary glands, which produce salivary amylase.

Question 3

What is the function of the oesophagus in digestion?

Answer 3

To connect the mouth to the stomach.

Question 4

What is the function of the stomach in digestion?

Answer 4

1. To produce pepsin (a protease enzyme).

2. To produce hydrochloric acid, in order to kill bacteria and provide the pH in which pepsin works optimally.

Question 5

What is the function of the liver in digestion?

Answer 5

To produce bile.

Question 6

What is the function of the gall bladder in digestion?

Answer 6

To store bile.

Question 7

What is the function of the pancreas in digestion?

Answer 7

To produce amylase, protease and lipase enzymes, which are then released into the small intestine.

Question 8

What is the function of the small intestine in digestion, and what are the names of its three parts?

Answer 8

The three parts of the small intestine are the duodenum, the jejunum and the ileum.
The function of the small intestine is to produce amylase, protease and lipase enzymes in order to complete digestion. It also absorbs nutrients from digested food into the body.

Question 9

What is the function of the large intestine in digestion?

Answer 9

To absorb excess water from digested food.

Question 10

Where is bile:

a) produced
b) stored
c) used?

Answer 10

a) The liver
b) The gall bladder
c) The small intestine

Question 11

What is the function of bile in digestion

Answer 11

1. To neutralise - and basify - food that has passed through stomach acids so that digestive enzymes are able to work on it optimally.
2. To emulsify fats. Bile breaks down fats into extremely small droplets - creating a larger surface area for lipases to work on, thus making digestion faster.

Question 12

How is the small intestine adapted for the efficient absorption of nutrients?

Answer 12

1. The walls of the small intestine are covered with millions of tiny projections - villi - which are, in turn, covered with microvilli. This increases the small intestine’s surface area - allowing for more absorption.
2. In order to assist quick absorption, the villi have a single, permeable layer of cells and a good blood supply.

Question 13

What is peristalsis?

Answer 13

The process by which muscles contract and relax in order to move food down the alimentary canal.