Introduction

Control and coordination in organisms is achieved through the nervous system (fast, electrical signals) and the endocrine system (slow, chemical hormones). Plants coordinate using phytohormones.

Key Points at a Glance

1. Neuron: cell body + dendrites (receive) + axon (transmit) + synapse (chemical transmission between neurons)
2. Reflex arc: receptor → sensory nerve → spinal cord → motor nerve → effector; involuntary, fast
3. Brain: cerebrum (thinking, memory), cerebellum (balance), medulla (involuntary actions); protected by skull + CSF
4. Plant tropisms: phototropism (light), geotropism (gravity), hydrotropism (water), chemotropism (chemicals), thigmotropism (touch)
5. Nastic movements: non-directional; Mimosa pudica folds on touch (thigmonasty)
6. Plant hormones: auxin (elongation), gibberellin (stem growth), cytokinin (cell division), abscisic acid (growth inhibitor), ethylene (ripening)
7. Animal hormones: GH (growth), thyroxine (metabolism, needs iodine), adrenaline (fight-or-flight), insulin (lowers blood sugar), testosterone/estrogen (sexual characters)
8. Feedback mechanism: blood sugar regulated by insulin (lowers) and glucagon (raises); homeostasis

Real-World Connections

Reflexes protect us from burns and injury; diabetes is managed with insulin injections; iodised salt prevents goitre; artificial ripening of fruits uses ethylene gas.

Quick Self-Test (5 Questions)

1. What is the most important concept you learned from this chapter?
2. Can you write three key equations/formulae from this chapter from memory?
3. Draw a labelled diagram relevant to this chapter without looking at your notes.
4. Explain one real-world application of a concept from this chapter.
5. What is one common mistake students make in this chapter, and how can you avoid it?

Further Study

• NCERT Textbook Chapter 6
• NCERT Exemplar Problems
• Bright Tutorials Detailed Notes: ch06-control-coordination.html
• Bright Tutorials Practice Questions: ch06-control-coordination.html
• Previous Year CBSE Board Papers