Question 4
What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise?
The specialised tips of some nerve cells that detect the changes in our environment by receiving the stimulus are called receptors. These receptors are usually located in our sense organs, such as inner ear, nose, tongue, skin etc. For example, gustatory receptors (tongue) will detect taste while olfactory receptors (nose) will detect smell.
If receptors are not working properly, the external stimulus won't be able to stimulate receptors and no nerve impulse will be generated. The result will be that the body would not respond to changes in the surroundings.
Chapter 6: Control and Coordination — Quick Revision Guide
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
- Neuron: cell body + dendrites (receive) + axon (transmit) + synapse (chemical transmission between neurons)
- Reflex arc: receptor → sensory nerve → spinal cord → motor nerve → effector; involuntary, fast
- Brain: cerebrum (thinking, memory), cerebellum (balance), medulla (involuntary actions); protected by skull + CSF
- Plant tropisms: phototropism (light), geotropism (gravity), hydrotropism (water), chemotropism (chemicals), thigmotropism (touch)
- Nastic movements: non-directional; Mimosa pudica folds on touch (thigmonasty)
- Plant hormones: auxin (elongation), gibberellin (stem growth), cytokinin (cell division), abscisic acid (growth inhibitor), ethylene (ripening)
- Animal hormones: GH (growth), thyroxine (metabolism, needs iodine), adrenaline (fight-or-flight), insulin (lowers blood sugar), testosterone/estrogen (sexual characters)
- 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)
- What is the most important concept you learned from this chapter?
- Can you write three key equations/formulae from this chapter from memory?
- Draw a labelled diagram relevant to this chapter without looking at your notes.
- Explain one real-world application of a concept from this chapter.
- 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