Part 3: The Digestive System

Question 1

What is the function of the mouth (teeth)?

Answer 1

The teeth physically digest food into smaller pieces to aid chemical digestion.

Question 2

What is the function of the mouth (tongue)?

Answer 2

The tongue (a muscle) helps you to move food to the back of your mouth so you can swallow it.

Question 3

What is the function of the mouth (salivary glands)?

Answer 3

The salivary glands contain an enzyme (amylase) that starts to break large carbohydrates down into simple sugars.

Question 4

What is the function of the oesophagus?

Answer 4

The oesophagus passes food down to the stomach.

Question 5

What is the function of the stomach?

Answer 5

The stomach churns up the food to mix the food with digestive juices.

Question 6

What is the function of the pancreas?

Answer 6

The pancreas produces enzymes that are released into the small intestine.

Question 7

What is the function of the small intestine?

Answer 7

Small, soluble molecules that can be absorbed into the bloodstream are produced. Absorption happens in the second part of the small intestine, where all the useful substances pass into the bloodstream.

Question 8

What is the function of the liver?

Answer 8

The liver makes bile.

Question 9

What is the function of the gall bladder?

Answer 9

The gall bladder stores bile.

Question 10

What is the function of the large intestine?

Answer 10

The large intestine absorbs water from the waste material.

Question 11

What is the function of the rectum?

Answer 11

The rectum stores the waste until it is removed from the body by the anus.

Question 12

Which organs are involved in physical digestion?

Answer 12

Mouth and stomach

Question 13

Which organs are involved in chemical digestion?

Answer 13

Mouth, stomach, small intestine

Question 14

Which organs are involved in the absorption of food?

Answer 14

Small intestine and large intestine (water)

Question 15

Name the adaptations of the small intestine to help it increase the efficiency of absorption (5)

Answer 15

Long length: 6- 7 metres
Highly folded surface to increase the surface in contact with digested food.
Villi: finger like projections to further increase the surface area
Microvilli: cells covering the villi have tiny projecting folds to increase the surface even further.
Mitochondria: cells lining the villi have lots of mitochondria to provide energy to enable them to absorb substances by active transport.

Question 16

Explain how the villus (plural villi) helps with the absorption of digested food (3)

Answer 16

Rich blood supply produces a steep concentration gradient for efficient diffusion.
Large surface area for diffusion.
Thin wall (only one cell thick), so there is only a short distance across which diffusion takes place
The villi have lots of mitochondria, which produce the energy needed to absorb substances into the bloodstream.

Question 17

Which organs does food not enter?

Answer 17

The pancreas, gall bladder, and liver

Question 18

Where does food not enter?