Digestive System

Question 1

The digestive system has two main roles. Briefly describe each of them.

Answer 1

Digestion - process of breaking down large food molecules into smaller molecules

Absorption - process of absorbing these small food molecules into the body

Question 2

When we chew food, our teeth physically break the food down into smaller pieces.

How does this help?

Answer 2

• It increases the surface area for enzymes to act on
• It make the food easier to swallow

Question 3

how do the salivary glands help in the process of digestion?

Answer 3

The salivary glands in our mouth release saliva which lubricates the food and makes it easier to swallow.

It also contains the enzyme amylase, which breaks down starch into maltose.

Question 4

What is the official name for the tube that carries food from the mouth to the stomach.

Answer 4

Oesophagus

Question 5

3 roles of the stomach

Answer 5

1. The stomach contracts its muscular walls to churn and mix the food.
2. It produces pepsin, which is a type of protease enzyme, and breaks proteins down into amino acids.
3. It produces hydrochloric acid, which:
   a) provides the right pH for pepsin to function b) kills microorganisms.

Question 6

2 roles of bile

Answer 6

(made by the liver,stored in the gallbladder, released into the small intestine where) it helps in two ways:

• to emulsify lipids
• neutralise the acid from the stomach, which bile can do because it is alkaline

Question 7

Which enzymes does the pancreas produce?

Answer 7

Amylase, proteases, and lipases

Question 8

Which enzymes does the small intestine produce?

Answer 8

Amylase, proteases, and lipases

Question 9

Villi are finger-like protrusions of the small intestine that are responsible for absorbing nutrients into the body.

Give three ways in which villi are adapted for this role.

Answer 9

• There are many villi, - which gives them a large total surface area to absorb nutrients
• single layer of cells on their surface - nutrients only have to diffuse a short distance.
• good blood supply - which maintains a strong concentration gradient between the lumen and the blood
• The cells lining the villi have microvilli on their surface - which further increases the surface area

Question 10

What is the main role of the large intestine?

Answer 10

absorb water

Question 11

what is the energy from food used for?

Answer 11

to keep out metabolism running

Question 12

mechanical digestion is found in the…

Answer 12

mouth and stomach

Question 13

where is bile stored before being released into the stomach?

Answer 13

the gall bladder

Question 14

where is bile made?

Answer 14

in the liver

Question 15

the line of the _________ is an ________ surface to the _________

Answer 15

the line of the small intestine is an exchange surface to the blood stream

Question 16

what enzyme does the stomach produce

Answer 16

pepsin (a protease enzyme)

Question 17

where is feces stored?

Answer 17

the rectum