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