Year 4 Science: What each part of the digestive system does
Part of the Year 4 Science teeth and the digestive system chapter. Chapter overview · whole chapter on one page
What each part of the digestive system does
Each part of the digestive system has a simple job. The table shows what each part does.
| Part | What it does |
|---|---|
| Mouth | teeth chew the food, and saliva starts to break down starchy food |
| Oesophagus | a tube; muscles push the food down to the stomach |
| Stomach | churns the food and breaks it down with digestive juices |
| Small intestine | finishes breaking down the food, and absorbs the nutrients into the blood |
| Large intestine | absorbs water from the food that is left over |
| Rectum | stores the waste until it is ready to leave the body |
| Anus | the opening where the waste leaves the body |
Key ideas
- The mouth: teeth chew the food, and saliva starts to break it down.
- The oesophagus: muscles push the food down to the stomach.
- The stomach: churns the food and breaks it down with digestive juices.
- The small intestine: absorbs the nutrients into the blood.
- The large intestine: absorbs water. The rectum stores the waste, and the anus lets it out.
Method. Find the part that absorbs.
- Read the table. The small intestine absorbs the nutrients into the blood.absorbs nutrients
- Name the part. So the small intestine is the part that absorbs nutrients.Small intestine
- Write the answer. Small intestine
Check. Nutrients pass into the blood from the small intestine. ✓
Method. Find the part that churns.
- Read the table. The stomach churns the food and breaks it down with juices.churns
- Name the part. So the stomach is the part that churns the food.Stomach
- Write the answer. Stomach
Check. The stomach mixes the food with digestive juices. ✓
Method. Find the part that absorbs water.
- Read the table. The large intestine absorbs water from the food that is left.absorbs water
- Name the part. So the large intestine absorbs water.Large intestine
- Write the answer. Large intestine
Check. The large intestine is the last part that absorbs. ✓
Watch out
Watch out: the small intestine absorbs nutrients into the blood, and the large intestine absorbs water. Do not mix up the two parts.
Try it at home or school (with a grown-up). Chew a plain cracker, or a piece of bread, slowly with a grown-up, and notice the taste after a minute. Do not swallow it whole. Spit it into a tissue when finished.
Exam tip
Grown-up tip. Ask: “What is the mouth doing to the food? What does the stomach do with it?” Let your child name one job for each part.
Exercise 5B What each part of the digestive system does
Method. Read the table in section 5.2.
- Read the table. The mouth uses saliva to start breaking down the food.saliva
- Write the answer. Mouth
Check. Saliva is made in the mouth. ✓
Method. Read the table in section 5.2.
- Read the table. The stomach churns the food and breaks it down.churns
- Write the answer. Stomach
Check. The stomach mixes the food with juices. ✓
Method. Read the table in section 5.2.
- Read the table. The small intestine absorbs the nutrients into the blood.nutrients
- Write the answer. Small intestine
Check. Nutrients are absorbed into the blood. ✓
Method. Read the table in section 5.2.
- Read the table. The large intestine absorbs water.water
- Write the answer. Large intestine
Check. The large intestine removes water from the waste. ✓
Method. Read the table in section 5.2.
- Read the table. Muscles in the oesophagus push the food down to the stomach.push
- Write the answer. pushes
Check. The oesophagus carries food; it does not store it. ✓
Method. Read the table in section 5.2.
- Read the table. The rectum stores the waste.stores
- Write the answer. Rectum
Check. The anus lets the waste out. ✓
Method. Read the table in section 5.2.
- Read the table. The anus is the opening where the waste leaves the body.leaves the body
- Write the answer. removes
Check. The anus removes waste from the body. ✓
Method. Read the table in section 5.2.
- Read the table. The small intestine absorbs nutrients into the blood.nutrients
- Write the answer. nutrients
Check. Nutrients are the useful parts of food. ✓
Method. Think about which part is the longest.
- Think about the size. The small intestine is the longest part of the digestive tube.longest
- Name the part. So the answer is the small intestine.Small intestine
- Write the answer. Small intestine
Check. The small intestine is long and narrow. ✓
Method. Read the table in section 5.2.
- Read the table. The stomach churns and breaks down food; the small intestine absorbs nutrients.small intestine
- Decide. So Ruby is not right.no
- Write the answer. no
Check. Absorption into the blood happens in the small intestine. ✓
Method. Read the table in section 5.2.
- Read the table. The mouth chews the food, but absorption happens in the small intestine.chews
- Decide. So Mo is not right.no
- Write the answer. no
Check. Chewing breaks the food up, but does not absorb it. ✓
Method. Think about what saliva does.
- Think about saliva. Saliva starts to break down starchy food in the mouth.starch
- Write the prediction. So the cracker should taste sweeter after a minute of chewing.sweeter
- Write the answer. Accept any prediction with a reason, such as: it will taste sweeter, because saliva starts to break the starch down.
Check. Test your prediction safely with a grown-up. ✓
Method. Think about each part.
- Think about the stomach. The stomach churns and breaks food down.breaks food down
- Think about the small intestine. The small intestine finishes the digestion and absorbs nutrients.absorbs nutrients
- Write the answer. Accept any sentence that says the stomach breaks food down, and the small intestine finishes breaking it down and absorbs nutrients.
Check. Digestion happens in more than one part. ✓