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Auralith Learning

Year 8 · Science · Nutrition and digestion · Lesson 2

The digestive system

The organs of the digestive system and what each one does, mechanical and chemical digestion, absorption by the villi, and the jobs of bile.

Whiteboard video lesson: The digestive system

26-minute video lesson

Teaching, worked examples and 20 practice questions solved step by step.

Watch free for a month

What your child will learn

  • Explain what digestion is and why it's needed
  • Name and label the organs of the digestive system
  • Describe what happens in each organ
  • Explain how villi are adapted for absorption
  • Describe the jobs of bile and the pancreas

The method

  1. Digestion breaks large insoluble molecules into small soluble ones.
  2. Food path: mouth, oesophagus, stomach, small intestine, large intestine, rectum, anus.
  3. Nutrients are absorbed in the small intestine; water in the large intestine.
  4. Villi have a large surface area, thin walls and a good blood supply.

Key words: digestion, oesophagus, stomach, small intestine, large intestine, villi, absorption, bile, egestion.

Worked examples

The first three practice questions from the lesson, with every step.

Question 1

Look at the diagram. Name the organ labelled Y, and give its job.

  1. Step 1: Find the label
  2. Step 2: Y = oesophagus
  3. Step 3: Job: muscles squeeze food down to the stomach

Answer: Oesophagus: muscles squeeze food down to the stomach

Question 2

Look at the diagram. Name the organ labelled A, and give its job.

  1. Step 1: Find the label
  2. Step 2: A = small intestine
  3. Step 3: Job: digestion finishes; nutrients are absorbed into the blood

Answer: Small intestine: digestion finishes; nutrients are absorbed into the blood

Question 3

Look at the diagram. Name the organ labelled B, and give its job.

  1. Step 1: Find the label
  2. Step 2: B = large intestine
  3. Step 3: Job: water is absorbed

Answer: Large intestine: water is absorbed