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IGCSE · Cambridge (CIE) · 0654

Trace the alimentary canal from mouth to anus

Identify the continuous route taken by food.

Section B7.2 · Digestive system

Digestive system · Cambridge IGCSE 0654 · B7.2

Mapped to the named 0654 section using teaching from the corresponding single-science course. A 0654-specific review of every Core and Supplement objective is still in progress. Written practice is self-checked; it does not demonstrate supervised laboratory competence or award an official Cambridge grade.

Before you begin

  • Recall large and small nutrient molecules, cell membranes and enzyme specificity.
  • Use the stated diagram keys and evidence; models are not to scale.

Work on paper. Try each question before revealing help, and explain why your method works.

Quick readiness check

Which tube leads to the stomach?

What you will learn

  • Identify the continuous route taken by food.
  • Use organ connections to identify an unfamiliar diagram.
Original route schematic: mouth → oesophagus → stomach → small intestine (duodenum onward to ileum) → colon → rectum → anus. Associated organs supply secretions and are not additional food-route segments.Trace the food routeFood entersMouth → oesophagus → stomachSmall intestineDuodenum → onward to ileumFinal canal regionsColon → rectum → anus
Original route schematic: mouth → oesophagus → stomach → small intestine (duodenum onward to ileum) → colon → rectum → anus. Associated organs supply secretions and are not additional food-route segments.

Follow the lumen

The alimentary canal is a continuous tube: mouth → oesophagus → stomach → small intestine → large intestine → anus. The duodenum is the first small-intestine region after the stomach; the ileum is its final region.

The large intestine includes the colon and rectum. Faeces are stored in the rectum before leaving through the anus. The names small and large refer mainly to diameter, not a claim that the small intestine is shorter.

Identify by connections

In a diagram, trace the tube rather than identifying an organ only from colour. The oesophagus connects the mouth region with the stomach. The coiled small intestine lies between the stomach/duodenum and the colon.

Liver and pancreas are associated organs, not segments through which the swallowed food normally passes. Their secretions reach the canal through ducts. A schematic straightens or enlarges parts and does not give their measured lengths.

Sources for this lesson

Pause and explain

Which region follows the stomach?

Put the idea to work

Worked example

A route lists mouth, stomach, liver, colon and anus. Correct the food pathway.

Show the worked solution
  1. Insert oesophagus after mouth.
  2. Insert small intestine after stomach.
  3. Remove liver as a food-canal segment.

Answer Mouth → oesophagus → stomach → small intestine (duodenum then onward to ileum) → colon → rectum → anus.

Try a topic test

Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.

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From guided practice to a new situation

Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.

1 · Guided

Order oesophagus, mouth, stomach, colon and small intestine along the food route.

Give me a hint

Begin where food enters.

Compare my reasoning
  1. Mouth then oesophagus.
  2. Stomach then small intestine.
  3. Colon after small intestine.

Mouth → oesophagus → stomach → small intestine → colon.

Look for these in your work

  • All five correctly ordered.
  • No associated organ inserted.
2 · Independent

Name the first and final small-intestine regions required here and the next large-intestine region.

Give me a hint

Use duodenum and ileum.

Compare my reasoning
  1. First: duodenum.
  2. Final: ileum.
  3. Then colon.

Duodenum; ileum; colon.

Look for these in your work

  • Correct regions.
  • Correct sequence.
3 · Transfer

An unfamiliar monochrome diagram shows a sac receiving a tube from the mouth and emptying into a coiled intestine. Identify the sac and explain your evidence.

Give me a hint

Use connections rather than colour.

Compare my reasoning
  1. Tube from mouth is oesophagus.
  2. Sac between oesophagus and intestine is stomach.

The stomach, identified by its connections to the oesophagus and small intestine.

Look for these in your work

  • Name stomach.
  • Use structural connections.

Common mistakes

  • Do not send swallowed food through the liver or pancreas.
  • The rectum and anus are distinct structures.
Recall without your notes

What can you explain now?

Which region follows the stomach?

Compare with the explanation

Duodenum of the small intestine.

It receives material leaving the stomach.

After trying it yourself, choose your next review. This is your self-assessment.

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Make it stick

Trace the complete food route and identify the two named small-intestine regions.

If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.

Keep learning Sciences — Co-ordinated (Double)

Course scope and assessment

This 2028–2029 pathway maps all 152 detailed subject-content sections in the published 0654 syllabus to original teaching and staged practice. It adapts teaching from the related single-science pathways and excludes clear 0610-only topics such as classification systems, human excretion, tropic responses, food supply, population dynamics, detailed pollution and biotechnology. Some explanations may include wider single-science context. A 0654-specific objective-by-objective review, Core/Supplement audit, human subject-teacher review, supervised laboratory experience and cumulative assessment remain in progress. Written practice is self-checked and does not predict an official grade. The 2025–2027 syllabus has not been reconciled here; choose the 2028–2029 syllabus only.

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