Topics Covered

10 key topics in this chapter

Nervous System in Animals

Neurons: Structure & Function

Reflex Arc & Reflex Action

Human Brain: Parts & Functions

Cerebrum, Cerebellum, Medulla

Nervous System in Plants

Tropic Movements

Chemical Coordination

Endocrine Glands & Hormones

Feedback Mechanism

Study Resources

Formula / Reaction / Rule	Expression
Reflex Path	\(Stimulus → Receptor → CNS → Effector → Response\)
Synapse	\(Neurotransmitter carries signal across gap\)
Insulin action	\(High glucose → Insulin secreted → Glucose → Glycogen\)
Adrenaline	\(Stress → Adrenal glands → Adrenaline → Heart rate ↑\)
Thyroxine	\(Controls basal metabolic rate; needs iodine\)
Feedback loop	\(Hormone level → gland detects → adjusts secretion\)

Reflex arc: Receptor → Sensory neuron → Spinal cord (relay neuron) → Motor neuron → Effector. No brain involvement.

Brain parts: Cerebrum (thought, memory), Cerebellum (balance, posture), Medulla oblongata (involuntary — heart, breathing).

Tropic movements in plants are directional responses to stimuli. Phototropism (light), Geotropism (gravity), Hydrotropism (water).

Insulin (pancreas, lowers blood sugar), Thyroxine (thyroid, controls metabolism), Adrenaline (adrenal glands, fight/flight).