Do now! Find your “Sound Target sheet”. Make sure your exam result and level is written there....
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Transcript of Do now! Find your “Sound Target sheet”. Make sure your exam result and level is written there....
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
Last lessonThe digestive system
A long tube!
We can think of the digestive system as if it were a long tube
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.
The journey begins in the mouth
Ingestion
Putting food into the mouth is called ingestion (feeding).
Teeth
The incisors help us to bite the food into large chunks the food
Teeth
The molars help to grind the food into even smaller pieces.
Saliva
Salivary glands produce saliva which makes the food moist and easier to swallow
Saliva
Saliva also contains enzymes, which are chemicals which break down the food chemically.
Gullet/oesophagus/food pipe
The gullet is a tube with a muscular wall that squeezes the food into the stomach
Gullet/oesophagus/food pipe
To show that this is true you can try drinking water whilst standing on your head!
Gullet/oesophagus/food pipe
It takes around 10 seconds for food to travel from the mouth to the stomach
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
Stomach
The stomach churns the food for about 2 – 4 hours
Small intestine
The stomach squirts food into the small intestine.
Small intestine
Here food is mixed with digestive juices from the liver and pancreas.
Small intestine
Bile from the liver breaks up fat.
Small intestine
Pancreatic juice neutralises the stomach acid and contains enzymes that digest carbohydrates, proteins and fats.
(small intestine)
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.
Surface area
The lining of the small intestine has a large surface area to help this to happen.
villi
Small intestine
The small intestine is about 6.5 metres long and food spends up to 6 hours here.
Large intestine
The large intestine absorbs water from what remains of the food.
Large intestine
Semi-solid (if you’re lucky!) faeces are formed after 12-36 hours in the large intestine.
Rectum
Faeces are stored in the rectum until there is a convenient moment to get rid of them!
Anus
They exit through your anus. This is called egestion.
Peristalsis
Throughout its journey, the food is squeezed down the digestive system by muscular walls in a process called peristalsis.
Role play?!
Draw the sentence!
Homework
• Finish the “Draw the sentence” for Wednesday 14th October
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