Let´s ALL act out the digestive system!

Absorption, intestine, villus, duodenum enzymes, capillary Absorption of food L/O: To understand how food is digested and absorbed into the blood stream Starter 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 enzymes A – 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 WORDS Absorption, 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 Vein Lymphatic 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!