Chapter 14 of 19
Revision Notes
The Respiratory System — Revision Notes
ICSE · Class 9 · Biology
The Respiratory System revision notes for ICSE Class 9 Biology: 4 topics in quick points. Part of the ICSE Class 9 Biology syllabus.
45 questions40 flashcards5 concepts
Interactive on Super Tutor
Studying The Respiratory System? Get the full interactive chapter.
Quizzes, flashcards, AI doubt-solver and a step-by-step study plan — built for revision notes and more.
Free trial, no card needed.

Super Tutor
One of 10 illustrations for The Respiratory System in Super Tutor — alongside flashcards, concept maps and practice questions.
Key Topics to Revise
1
1. Need for Respiration and Cellular Respiration
- Respiration involves the breakdown of glucose using oxygen.
- The overall reaction is: C6H12O6 + 6O2 → 6CO2 + 6H2O + energy.
- This reaction occurs inside living cells, so it is called cellular or tissue respiration.
2
2. Aerobic and Anaerobic Respiration
- Aerobic respiration uses oxygen and is the normal type in animals.
- Anaerobic respiration is respiration without oxygen.
- Anaerobic respiration in animals is exceptional and temporary.
3
3. Parts of Respiration
- Respiration has four major parts in humans.
- Breathing is the physical process of taking air in and forcing it out of the lungs.
- Gaseous transport means oxygen is carried by RBCs and carbon dioxide is carried back to the lungs as bicarbonates in plasma and as carbamino-haemoglobin with haemoglobin.
4
4. Respiratory Organs and Their Functions
- The human respiratory system includes the nose, pharynx, larynx, trachea, bronchi, and lungs.
- The nose has two nostrils separated by a cartilaginous septum.
- The inner lining of the nasal chambers warms air, adds moisture, and traps harmful particles with mucus.
Get complete notes with diagrams and examples
Full NotesKey Concepts
Respiration is the chemical processAerobic respiration uses oxygen to breakAnaerobic respiration happens without oxygenBreathing is the physical processThe nose
Frequently Asked Questions
What are the important topics in The Respiratory System for ICSE Class 9 Biology?
Key topics in The Respiratory System include Need for Respiration and Cellular Respiration, Aerobic and Anaerobic Respiration, Parts of Respiration, Respiratory Organs and Their Functions. Study these first, then practise questions on each for Class 9 exams.
How should I revise The Respiratory System for Class 9 exams?
Learn the core ideas first, then work through the 45 practice questions on The Respiratory 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.
More resources for The Respiratory System
For serious students
Get the full The Respiratory System chapter — start free.
Quizzes, flashcards, an AI doubt solver and a study plan for ICSE Class 9 Biology. Free to start, no card needed.