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I. Chapter Summary
This chapter explains how living organisms maintain internal coordination through nervous and hormonal systems. It covers the human nervous system—its structure and functioning, types of responses (reflex, voluntary, involuntary)—and the role of hormones in animals and plants. It introduces the brain, spinal cord, and reflex arc as key components in coordination, and also explores how plants coordinate through chemicals like auxins, gibberellins, and abscisic acid. The chapter concludes with the endocrine glands in humans and the hormones they secrete.
II. Key Concepts Covered
| Concept | Description |
| Coordination | The ability of an organism to integrate and respond to stimuli. |
| Nervous System | Includes brain, spinal cord, nerves; controls voluntary and involuntary actions. |
| Reflex Action | An automatic, quick response to a stimulus (e.g., withdrawing hand from flame). |
| Reflex Arc | The pathway through which a reflex action occurs—includes receptor, sensory neuron, spinal cord, motor neuron, and effector. |
| Brain Parts | |
| – Forebrain: Thinking, memory, voluntary actions | |
| – Midbrain: Eye movement | |
| – Hindbrain: Involuntary actions (e.g., heartbeat, balance) | |
| Plant Hormones (Phytohormones) | |
| – Auxin: Cell elongation | |
| – Gibberellin: Growth | |
| – Cytokinin: Cell division | |
| – Abscisic acid: Inhibits growth, promotes dormancy | |
| Tropism | Directional movement of plants in response to stimuli (light, gravity, etc.). |
| Endocrine System | Glands that secrete hormones directly into blood to regulate body functions. |
| e.g., Thyroid, Pituitary, Adrenal, Pancreas, Testes/Ovaries |
III. Important Questions
(A) Multiple Choice Questions (1 Mark)
- Which part of the brain controls voluntary actions?
a) Cerebellum
b) Medulla
c) Cerebrum ✅ (PYQ 2020)
d) Pons - Which plant hormone is responsible for cell elongation?
a) Gibberellin
b) Auxin ✅ (PYQ 2019)
c) Cytokinin
d) Abscisic acid - Which gland secretes insulin?
a) Pituitary
b) Thyroid
c) Adrenal
d) Pancreas ✅ (PYQ 2021) - Which of the following is not a tropic movement in plants?
a) Geotropism
b) Phototropism
c) Chemotropism
d) Reflex ✅
(B) Short Answer Questions (2/3 Marks)
- What is a reflex arc? Draw its labeled diagram. (PYQ 2020)
- State two differences between sensory and motor neurons.
- Explain phototropism and give one example.
- How do auxins help in phototropic movement of plants? (PYQ 2021)
(C) Long Answer Questions (5 Marks)
- Describe the structure and function of the human brain with a labeled diagram.
- Explain the feedback mechanism involved in the regulation of hormone secretion. Give one example.
- Differentiate between nervous control and hormonal control in humans.
- Describe the role of phytohormones in plants. Mention the effects of at least four different hormones.
(D) HOTS (Higher Order Thinking Skills)
- Why is it advised not to make sudden movements when standing up quickly? Relate your answer with coordination in the human body.
- Why do organisms have two control systems—nervous and endocrine? What advantages does each offer?
IV. Key Formulas/Concepts
While this chapter is mostly conceptual, key definitions and examples are crucial.
| Term | Explanation |
| Reflex Arc | Receptor → Sensory Neuron → Spinal Cord → Motor Neuron → Effector |
| Hormone | A chemical messenger secreted by endocrine glands directly into the blood. |
| Phototropism | Growth of plant towards light due to unequal distribution of auxin. |
| Endocrine Glands & Hormones | |
| – Pituitary: Growth hormone | |
| – Thyroid: Thyroxine | |
| – Adrenal: Adrenaline | |
| – Pancreas: Insulin | |
| – Ovaries/Testes: Estrogen/Testosterone |
V. Deleted Portions (CBSE 2025–2026)
No portions have been deleted from this chapter as per the rationalized NCERT textbooks.
VI. Chapter-Wise Marks Bifurcation (Estimated – CBSE 2025–2026)
| Unit/Chapter | Estimated Marks | Type of Questions Typically Asked |
| Chapter 6: Control and Coordination | 7–9 Marks | 1 Long Answer, 2–3 Short Answers, 2–3 MCQs |
VII. Previous Year Questions (PYQs)
| Year | Marks | Question |
| 2021 | 2 | How do auxins help in the phototropic response of plants? |
| 2020 | 3 | What is reflex arc? Draw and label its diagram. |
| 2019 | 1 | Which plant hormone is responsible for cell elongation? (Auxin) |
| 2018 | 5 | Explain the structure and functions of the human brain. Draw a diagram. |
VIII. Real-World Application Examples
| Concept | Application |
| Reflex Action | Helps prevent injury (e.g., pulling hand from hot surface). |
| Hormonal Control | Used in treatment of diseases like diabetes (insulin therapy). |
| Plant Hormones | Used in agriculture for ripening (ethylene), growth (gibberellin). |
| Brain Coordination | Impacts sports performance, learning, and response time in daily activities. |
IX. Student Tips & Strategies for Success
Time Management
- Allocate 30 minutes every alternate day to understand nervous and hormonal control systems.
- Use mnemonics for remembering hormone names and functions.
Exam Preparation
- Practice labeled diagrams: reflex arc, human brain.
- Revise the functions of brain parts and hormones with flashcards.
- Practice NCERT textbook questions and PYQs.
Stress Management
- Use flowcharts and concept maps to connect the systems.
- Discuss real-life examples in group study to make learning relatable.
X. Career Guidance & Exploration (Class-Specific)
For Classes 9–10
Academic Streams
- Science: Biology, Neuroscience, Medicine
- Commerce: Healthcare Management, Biotech Business
- Arts: Psychology, Human Development, Education
Career Paths
- Doctor, Psychologist, Neuroscientist, Endocrinologist, Physiotherapist
Entrance Exams
- NTSE, Junior Science Olympiad, NSO, KVPY (Class 11+)
XI. Important Notes
- Refer to https://ncert.nic.in and https://cbseacademic.nic.in for official syllabus updates.
- Understand conceptual differences (e.g., reflex vs voluntary action, nervous vs endocrine control).
- Focus on application-based questions and labeled diagrams in your revisions.