Chapter 6: Control and Coordination
Simple, exam-focused CBSE Class 10 Science notes — star topics, concepts, common mistakes, and previous year question patterns, all on one page.
Chapter 6: Control and Coordination
⭐ Star Topics / Most Important
- Reflex arc
- Structure of a neuron
- Human brain — forebrain, midbrain, hindbrain
- Plant hormones and tropisms
- Endocrine glands and hormones
Detailed Chapter Notes
Coordination happens through the nervous system (fast, electrical) and endocrine system (slower, chemical, via hormones).
A neuron has dendrites (receive signals), cell body, and axon (sends signal via axon terminal). Signals cross to the next neuron at a synapse.
The reflex arc is a quick, automatic, involuntary response pathway: receptor → sensory neuron → spinal cord (relay neuron) → motor neuron → effector — faster than waiting for the brain.
The forebrain has the cerebrum (thinking, memory, voluntary actions). The midbrain and hindbrain have the cerebellum (balance, posture), medulla (involuntary actions like heartbeat, breathing), and pons.
Plants respond via tropisms: phototropism (towards light), geotropism (gravity), hydrotropism (water), thigmotropism (touch). Plant hormones: auxin (elongation, phototropism), gibberellin (stem growth), cytokinin (cell division), abscisic acid (growth inhibitor).
Endocrine glands: pituitary (master gland), thyroid (thyroxine, metabolism, needs iodine), pancreas (insulin, blood sugar — deficiency causes diabetes), adrenal (adrenaline, fight-or-flight).
Students often draw the reflex arc routed through the brain — wrong, the signal is processed at the spinal cord for speed. Also don't confuse auxin with gibberellin — auxin is specifically linked with phototropism, a frequently repeated diagram question.
Search on YouTube: Control and Coordination Class 10 reflex arc diagram for a visual walkthrough of this chapter.
- Draw a labelled diagram of a neuron (3 marks)
- What is a reflex action? Explain with an example (2/3 marks)
- How does chemical coordination occur in plants? (3 marks)
- What happens when the level of insulin in blood is low in a person? (2 marks, HOTS)
- Differentiate between phototropism and geotropism (2 marks)