Digestive System

Question 1

Digestion

Answer 1

This is breaking down food mechanically and chemically into small soluble substances.

Question 2

Absorption

Answer 2

This is the movement of soluble molecules into the blood. It is helped by the large surface area, and the presence of villi and microvilli

Question 3

Assimilation

Answer 3

When the small soluble molecules become part of the cells, ie are used for growth and repair and energy.

Question 4

Egestion

Answer 4

This is how undigested food (faeces) leave the body

Question 5

Mechanical digestion

Answer 5

Food is broken up by the teeth and tongue in the mouth and churned in the stomach by muscular movements

Question 6

Chemical digestion

Answer 6

Food is broken down by enzymes.

Question 7

Amylase

Answer 7

This enzyme breaks down starch into sugar. Eg bread, potatoes

Question 8

Protease

Answer 8

This enzyme breaks down proteins into soluble amino acids. Eg meat and fish

Question 9

Lipase

Answer 9

This enzyme breaks down fats and oils into smaller particles. Eg butter

Question 10

Simple sugars

Answer 10

Glucose is a soluble sugar that can be absorbed into our blood and transported to every cell in the body.

Question 11

Amino acids

Answer 11

These are small soluble protein molecules. There are 20 different types.

Question 12

Fatty acids and glycerol

Answer 12

These are the building blocks of fats.

Question 13

The mouth

Answer 13

Food is mechanically digested by the teeth.

Food is mixed with saliva which lubricates the food for swallowing.

Question 14

The oesophagus

Answer 14

Food is pushed along this tube from the mouth to the stomach by waves of muscles in a process called peristalsis

Question 15

Peristalsis

Answer 15

This helps to move food down the oesophagus. It works by the muscles above the food contracting and those below the food relaxing, squeezing the bolus of food into the stomach.

Question 16

The stomach

Answer 16

Foods that has been swallowed enters the stomach.
The stomach is a large muscular bag that is able to expand when large amounts of food have been eaten. Food stays in the stomach for about 4 hours.

Question 17

How the stomach works

Answer 17

• Food mechanically digested by constant muscle contraction.
• Glands in stomach wall release hydrochloric acid killing germs
• Provides correct pH for digestion of protein by protease enzyme that only works in acidic conditions.
• Rings of muscle at exit of the stomach let acidic partly digested food through into the duodenum bit by bit.

Question 18

Duodenum

Answer 18

This is the first part of the small intestine. Food enters here from the stomach, and is digested by enzymes.

Question 19

Gall bladder

Answer 19

This is a small pouch that stores a chemical called bile. Bile neutralises the acidic food from the stomach.

Question 20

Emulsion

Answer 20

This enables very small droplets of fat can be digested by lipase.

Question 21

Pancreas

Answer 21

This organ makes most of the enzymes and transports them into the small intestine.

Question 22

Ileum

Answer 22

This long part of the small intestine, is where chemical digestion is completed and the small soluble food molecules are absorbed.

Question 23

Absorption

Answer 23

This is when the small soluble molecules move into the blood stream and then into the cells of our bodies.

Question 24

Villi

Answer 24

These are projections from the surface of the ileum. They increase the surface area making absorption more efficient

Question 25

Microvilli

Answer 25

These are tiny projections on the villi, further increasing the surface area.

Question 26

Reabsorption

Answer 26

This is how the excess water leaves the large intestine, and enters the bloodstream. This makes the faeces more solid.

Question 27

Egestion

Answer 27

This is the removal of food molecules that our body has not been able to digest. Eg faeces.

Question 28

Excretion

Answer 28

This is the process of removing the waste products of metabolism from the body. Eg urine

Question 29

Ingestion

Answer 29

This is eating the food- putting it into our mouth.