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Do now! Find your “Sound Target sheet”. Make sure your exam result and level is written there. Write a TARGET for your next topic. Bunny suicide #4
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Last lesson The digestive system
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A long tube! We can think of the digestive system as if it were a long tube
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Breaking up of food During its journey down the tube, food is gradually broken down into smaller parts until it can be absorbed by the blood. This is called digestion.
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The journey begins in the mouth
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Ingestion Putting food into the mouth is called ingestion (feeding).
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Teeth The incisors help us to bite the food into large chunks the food
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Teeth The molars help to grind the food into even smaller pieces.
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Saliva Salivary glands produce saliva which makes the food moist and easier to swallow
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Saliva Saliva also contains enzymes, which are chemicals which break down the food chemically.
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Gullet/oesophagus/food pipe The gullet is a tube with a muscular wall that squeezes the food into the stomach
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Gullet/oesophagus/food pipe To show that this is true you can try drinking water whilst standing on your head!
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Gullet/oesophagus/food pipe It takes around 10 seconds for food to travel from the mouth to the stomach
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Stomach The stomach is a stretchy muscular bag which mixes the food with hydrochloric acid and pepsin, an enzyme which helps to digest protein molecules
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Stomach The stomach churns the food for about 2 – 4 hours
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Small intestine The stomach squirts food into the small intestine.
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Small intestine Here food is mixed with digestive juices from the liver and pancreas.
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Small intestine Bile from the liver breaks up fat.
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Small intestine Pancreatic juice neutralises the stomach acid and contains enzymes that digest carbohydrates, proteins and fats. (small intestine)
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Small intestine As food passes along the long tube of the small intestine, its molecules become small enough to be absorbed into the blood through the intestine walls.
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Surface area The lining of the small intestine has a large surface area to help this to happen. villi
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Small intestine The small intestine is about 6.5 metres long and food spends up to 6 hours here.
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Large intestine The large intestine absorbs water from what remains of the food.
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Large intestine Semi-solid (if you’re lucky!) faeces are formed after 12-36 hours in the large intestine.
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Rectum Faeces are stored in the rectum until there is a convenient moment to get rid of them!
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Anus They exit through your anus. This is called egestion.
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Peristalsis Throughout its journey, the food is squeezed down the digestive system by muscular walls in a process called peristalsis.
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Role play?!
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Draw the sentence!
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Homework Finish the “Draw the sentence” for Wednesday 14 th October
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Today’s lesson You’re going to try some questions about Digestion while Mr Porter speaks to you individually about your work. Read pages 10 and 11 and answer the questions
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