Lungs
Key Concepts Covered
This question tests your understanding of the following concepts from the chapter The Circulatory System: Question, Organ, Body, Blood, Get, Oxygenated. These are fundamental topics in Biology that students are expected to master as part of the ICSE Class 8 curriculum.
A thorough understanding of these concepts will help you answer similar questions confidently in your ICSE examinations. These topics are frequently tested in both objective and subjective sections of Biology papers. We recommend revising the relevant section of your textbook alongside practising these solved examples to build a strong foundation.
How to Write Short Answers
Short answer questions require concise, focused responses. Begin with a clear definition or statement that directly addresses the question. Support your answer with one or two key points or examples. Keep your response to 2-4 sentences. Avoid unnecessary elaboration but ensure you cover all parts of the question. Use subject-specific terminology to demonstrate your understanding.
Key Points to Remember
- Use precise scientific terminology as defined in the textbook.
- Draw and label diagrams neatly for full marks.
- Understand the difference between structure and function.
- Learn processes step-by-step in the correct sequence.
Practice more questions from The Circulatory System — Biology, Class 8 ICSE
Circulatory System – Interactive Study Guide
The circulatory system transports blood, oxygen, nutrients, and hormones throughout the body. It consists of the heart (pump), blood (transport medium), and blood vessels (pipelines).
Blood Components
| Component | Function | Key Fact |
|---|---|---|
| Plasma (55%) | Transports dissolved substances | 90% water, carries nutrients, hormones, waste |
| RBC | Carry oxygen | Biconcave disc, no nucleus, contain haemoglobin |
| WBC | Fight infections | Have nucleus, larger than RBC, immune defence |
| Platelets | Blood clotting | Cell fragments, no nucleus |
Blood Group Quick Reference
O = Universal Donor (no antigens) | AB = Universal Recipient (no antibodies)
| Group | Antigen | Antibody |
|---|---|---|
| A | A | anti-B |
| B | B | anti-A |
| AB | A & B | None |
| O | None | anti-A & anti-B |
Heart – Quick Facts
- 4 chambers: RA, RV, LA, LV
- 4 valves: Tricuspid (R), Bicuspid (L), 2 Semilunar
- Septum divides right (deoxy) from left (oxy)
- Left ventricle = thickest wall
Double Circulation
Pulmonary: RV → Pulmonary artery → Lungs → Pulmonary veins → LA
Systemic: LV → Aorta → Body → Vena cava → RA
Blood Vessels Comparison
| Arteries | Veins | Capillaries | |
|---|---|---|---|
| Direction | Away from heart | To heart | Connect A to V |
| Walls | Thick | Thin | 1 cell thick |
| Valves | No | Yes | No |
Self-Test Questions
- Why is the left ventricle wall thicker than the right?
- Draw and label the human heart.
- What is double circulation? Describe both circuits.
- Why is blood group O called universal donor?
- What is the function of valves in veins?