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Revision Notes

Digestive System — Revision Notes

ICSE · Class 9 · Biology

Digestive System revision notes for ICSE Class 9 Biology: 4 topics in quick points. Part of the ICSE Class 9 Biology syllabus.

45 questions40 flashcards8 formulas & key relations5 concepts

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A comprehensive labeled diagram of the human alimentary canal and its associated digestive glands, showing the path of food.
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Key Topics to Revise

1

1. Digestive System and Alimentary Canal

  • The digestive system has two main parts: the alimentary canal and digestive glands.
  • The alimentary canal is a muscular tube about 9 metres long.
  • It starts at the mouth and ends at the anus.
2

2. Teeth and Dentition

  • An adult human normally has 32 teeth.
  • Teeth help in biting, tearing, grinding, crushing, and speaking.
  • Human or mammalian teeth are heterodont, which means they are different in shape.
3

3. Saliva and Salivary Glands

  • Three pairs of salivary glands secrete saliva into the mouth: parotid, submandibular, and sublingual glands.
  • A person normally produces 1000 to 1500 ml of saliva daily.
  • Saliva has a pH of 6.8.
4

4. Swallowing, Peristalsis, and Oesophagus

  • Swallowing moves food from the mouth into the pharynx and then into the oesophagus.
  • Peristalsis is the wave of constrictions caused by the circular muscles of the gut pushing the food along.
  • Peristalsis occurs through all regions of the gut.

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Full Notes

Key Concepts

Digestion is the breakThe alimentary canal is a muscularAdult humans normally have 32 teethThree pairs of salivary glands secretePeristalsis is the wave of constrictions

Frequently Asked Questions

What are the important topics in Digestive System for ICSE Class 9 Biology?
Key topics in Digestive System include Digestive System and Alimentary Canal, Teeth and Dentition, Saliva and Salivary Glands, Swallowing, Peristalsis, and Oesophagus. Study these first, then practise questions on each for Class 9 exams.
How should I revise Digestive System for Class 9 exams?
Learn the core ideas first, then work through the 45 practice questions on Digestive System. Revise definitions regularly and use flashcards for quick recall before the exam.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.

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All ICSE Class 9 Biology Revision Notes

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