Let´s ALL act out the digestive system!

Absorption of foodL/O: To understand how food is digested and absorbed into

the blood streamStarter Recap: Name as many different enzymes

required for the breakdown of food.

Success Criteria:C – Describe how food is digested.B – Describe how food is broken down using enzymesA – Explain how the structure of the digestive system is adapted for absorbing food.A* - Explain, using examples, how the structure of the digestive system is adapted for absorbing food.

KEY WORDSAbsorption, intestine, villus,

duodenum enzymes, capillary

Learning outcomes

• Understand how absorption of soluble molecules takes place in the small and large intestines.

Absorption‘The passage of small food molecules through the wall of the small intestine and into vessels that can transport them within the body’

Small intestine

Structure of the Small Intestine

Colour me a villus!Colour in and label your cut-out of a villus using the words below:

•Thin epithelium (yellow)•Artery (red)•Vein (blue)•Blood capillary (red turning to blue)•Lacteal (green)•Lymphatic vessel (green)

Thin epithelium

Artery

VeinLymphatic vessel

Small Intestine• Small, soluble food molecules are

absorbed through the wall of the small intestine

• To absorb food molecules efficiently the small intestine has three main adaptations…….

1. A Large Surface Area• The small intestine is very long

-6m long

• The inner surface on the intestine is folded-covered with many finger-like projections called villi-greatly increase the surface area in contact with digested food

2. Thin Wall

• Each villus has an extremely thin wall-only one cell thick-rapid absorption

3. Good Blood Supply• Each villus is supplied with blood

vessels to receive the absorbed foods-glucose/amino acids/vitamins/minerals are absorbed into blood capillaries-products of fat digestion absorbed into lacteal

Duodenum• Pancreas secrete gastric juice

containing amylase, protease and lipase.

• Enzymes do not work well in acidic conditions so sodium hydrogencarbonate is an alkaline that is used to neutralise this.

• Bile enters the duodenum from the gall bladder.

• Bile is a yellow-green liquid that emulsifies fats by breaking large globules of fat into smaller globules to increase surface area so lipase enzymes act more efficiently

• Bile also helps to create an optimum pH for enzyme action

Ileum• Cells in wall of

Ileum secrete enzymes that complete digestion.

• Simple sugars, amino acids and glycerol are absorbed into the bloodstream here

Large Intestine• The small intestine absorbs food once

digested

• What passes into the large intestine?-water-waste material

• Large intestine-2m long-tubing is wider than small intestine

What does it do?• Absorbs water which is passed onto

the bloodstream

• Remaining material passed on into the rectum where it is removed from the body as faeces

Elimination‘The removal of faeces from the alimentary canal’

Let´s play bingo!Mouth Amylase Saliva Small

Intestine

Pancreas Fibre Fats Carbohydrates

Sugar Vitamins and Minerals

Protein Water

Large Intestine

Rectum Anus Oesophagus

Stomach Acid Enzymes Liver

Bile Teeth Tongue Peristalsis

Optimum Protease Churning Starch

Obesity Digestion Absorption Butter

Meat Pasta Oranges Amino acid

Glycerol Lipase Wholemeal Bread

Calcium

Choose TWELVE of the words below and write them into your blank bingo grid.

I will then read out questions to you about the human digestive system.

If you have written the answer to a question in your grid, cross it out.

The first person to cover up all their words wins!

Let´s play the loop game!