Human Organ Systems — Class 6 Science (Samacheer Kalvi)
TN State Board (Samacheer Kalvi) Class 6 Science, Term 2 — Chapter 6. How the body's systems work together.
1. About this chapter
This chapter covers the organ systems of the human body — skeletal, digestive, respiratory, circulatory and excretory — and the sense organs.
2. What is an organ system?
- A group of organs that work together to perform a particular function is an organ system.
- (Order: cells → tissues → organs → organ systems → organism.)
3. The major organ systems
| System | Key facts |
|---|---|
| Skeletal | the framework of bones; the skull protects the brain |
| Digestive | breaks down food (digestion); the stomach is a major digestive organ |
| Respiratory | the lungs are the main organs of respiration |
| Circulatory | the heart pumps blood, transporting food, oxygen and wastes (all of these); the heart is covered by a double-layered membrane called the pericardium |
| Excretory | removes wastes (excretion); the kidney filters extra salts and water; the ureter carries urine to the urinary bladder, which is passed out through the urethra |
4. The sense organs
- The five sense organs are the eyes, ears, nose, tongue and skin.
- The skin is the largest sense organ of the body. The important parts of the eye are the cornea, iris, lens and pupil.
5. Worked examples
Example 1. What is the main organ of respiration? The lungs.
Example 2. Which part of the skeleton protects the brain? The skull.
Example 3. Which is the largest sense organ? The skin.
6. Book-back questions (Samacheer Kalvi)
I. Choose the correct answer
- The circulatory system transports — (a) food / (b) oxygen / (c) wastes / (d) all of these. Ans: (d) all of these.
- The main organ of respiration in humans is the — (a) heart / (b) lungs. Ans: (b) lungs.
- The breakdown of food into smaller molecules is called — (a) excretion / (b) digestion. Ans: (b) digestion.
- A group of organs that work together is an — (a) tissue / (b) organ system. Ans: (b) organ system.
- The double-layered membrane around the heart is the — (a) pericardium / (b) cytoplasm. Ans: (a) pericardium.
II. Fill in the blanks 6. The part of the skeleton that protects the brain is the skull. 7. The process by which the body removes waste is excretion. 8. The skin is the largest sense organ in our body. 9. The ureter carries urine from the kidneys to the urinary bladder.
III. Answer briefly 10. Name the five sense organs. — The eyes, ears, nose, tongue and skin. 11. What is the function of the kidney? — It removes extra salts and water from the blood (excretion).
7. Common mistakes
- Mistake: Saying the heart is the organ of respiration. Fix: The lungs are the organs of respiration; the heart pumps blood.
- Mistake: Confusing the ureter and the urethra. Fix: The ureter carries urine to the bladder; the urethra passes it out of the body.
- Mistake: Naming the eye as the largest sense organ. Fix: The skin is the largest sense organ.
8. Quick revision
- Term 2 · Ch 6 · human organ systems.
- Organ system = organs working together; skeletal (skull protects brain), digestive (stomach, digestion), respiratory (lungs).
- Circulatory: heart (pericardium membrane) transports food/oxygen/wastes; excretory: kidney filters, ureter → bladder → urethra.
- Five sense organs: eyes, ears, nose, tongue, skin (skin is the largest); eye parts: cornea, iris, lens, pupil.
