review lesson digestion

• Biologie
• Middelbare school
• vwo
• Leerjaar 2

Review lesson 

Chapter 3:Food and digestion

The 7 nutrients we need

1. Proteins
2. Carbohydrates
3. Fats
4. Water
5. Vitamins
6. Minerals
7. Fibres

What do we need nutrients for? 

1. Growth and repair
2. Energy
3. To stay healthy 

GROWTH & REPAIR

ENERGY

STAYING HEALTHY

PROTEINS

CARBOHYDRATES

FATS

MINERALS

WATER

FIBRE

VITAMINS

Balanced Diet

• All nutrients
• Balanced amounts

Daily amount

-body size

-how active

-Gender

Unbalanced diet

• Obesity
• Anorexia
• Boulemia 

PHASES OF DIGESTION:

• INGESTION
• MECHANICAL DIGESTION
• CHEMICAL DIGESTION
• ABSORPTION
• EXCRETION
  

INGESTION:

MOVING THE FOOD INTO YOUR MOUTH

MECHANICAL DIGESTION:

• BREAKING THE FOOD INTO SMALLER PIECES.
• THIS IS DONE BY YOUR TEETH

CHEMICAL DIGESTION:

• BREAKING THE FOOD INTO EVEN SMALLER PIECES.
• USING ENZYMES TO BREAK DOWN THE FOOD MOLECULES. 

KERBOODLE PAGE 54

Chemical digestion Step 1

the place: the mouth (oesophagus)

the enzyme: amylase

the liquid: saliva (produced by the salivary glands)

the nutrient: carbohydrates

the products: glucose & maltose

The enzymes in your saliva start breaking down the carbohydrate molecules into maltose and glucose.

Down the tube!

Oesophagus

Peristalsis: moving food down your gut

In your stomach

Digestive juices

-Proteases -> digestion proteins -> amino acids

-Hydrochloric acid -> acid PH, best for the enzymes

-Rennin (only babies) makes milk solid, stays in the stomach longer

-Acidic environment also kills germs

In your small intestine

3 important liquids: 

-Pancreatic juice (carbohydrases, proteases and lipases)

-Bile from the liver, stored in the gall bladder

     -Bile is alkaline neutralises acid from the stomach, best Ph for the small intestine                 enzymes to work

      -Bile emulsifies fats, increases surface area of fats lipase enzymes to act upon

Intestinal juice (carbohydrases, proteases, lipases) Complete digestion of food, made by                            the wall of the small intestine

Stomach

Mouth

Small intestine

Rennin

Lipase

Protease

Amylase

Protease

Amylase

Absorption

-Small intestine

-food had to pass through the wall into the blood

contains millions of tiny, finger like processes called : Villi 

CHARACTERISTICS OF THE VILLUS:

- LARGE SURFACE AREA (MORE CONTACT MORE ABSORPTION)

- ONE CELL LAYER THICK (THIN WALLS FASTER ABSORPTION)

- GOOD BLOOD SUPPLY (FAST TRANSPORT OF NUTRIENTS TO THE REST OF THE BODY)

Large intestine

-Mainly fibre, dead cells, bacteria and water

-Water absorbed in the blood 

-Solid waste (feaces) stored in the rectum

Esophagus

Liver

Large intestine

Gall bladder

Stomach

Pancreas

Small intestine

anus

Ingestion

Mechanical digestion

Chemical digestion

Absorption

Egestion

MOVING THE FOOD INTO YOUR MOUTH

BREAKING THE FOOD INTO SMALLER PIECES.

THIS IS DONE BY YOUR TEETH

BREAKING THE FOOD INTO EVEN SMALLER PIECES.

USING ENZYMES TO BREAK DOWN THE FOOD MOLECULES. 

the movement of nutrients from the digestive system to the blood

The passing out of indigestible food through the anus, in the form of faeces.

Which nutrient provides energy?

1. carbohydrates
2. water
3. minerals
4. vitamins

Which nutrient provides use with building blocks for growth & repair?

1. carbohydrates
2. water
3. minerals
4. vitamins

What are potatoes a good source of?

1. carbohydrates
2. water
3. fibres
4. proteins

What are oranges a good source of ?

1. minerals
2. water
3. fibres
4. vitamins

What are eggs a good source of?

1. carbohydrates
2. water
3. fibres
4. proteins