Trace the alimentary canal from mouth to anus
Identify the continuous route taken by food.
Section B7.2 · Digestive system
Cross-referenced to the 2028–2029 0653 section using original teaching from the related single-science courses. A 0653-specific objective-by-objective and Core/Supplement review is in progress. Written practice is self-checked and 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.
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?
Worked example
A route lists mouth, stomach, liver, colon and anus. Correct the food pathway.
Show the worked solution
- Insert oesophagus after mouth.
- Insert small intestine after stomach.
- 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.
Test this topic →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.
Order oesophagus, mouth, stomach, colon and small intestine along the food route.
Give me a hint
Begin where food enters.
Compare my reasoning
- Mouth then oesophagus.
- Stomach then small intestine.
- Colon after small intestine.
Mouth → oesophagus → stomach → small intestine → colon.
Look for these in your work
- All five correctly ordered.
- No associated organ inserted.
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
- First: duodenum.
- Final: ileum.
- Then colon.
Duodenum; ileum; colon.
Look for these in your work
- Correct regions.
- Correct sequence.
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
- Tube from mouth is oesophagus.
- 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.
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.