WHAT IS REFLEX ARC

Reflex Arc 

Meaning

A reflex arc is the pathway followed by a nerve impulse during a reflex action (quick, automatic response without thinking).

 Reflex actions are controlled mainly by the spinal cord, not the brain (brain gets the information later).

•  Steps / Pathway of Reflex Arc

1. Receptor (Sense organ)
   Detects stimulus (like heat, pain)

2. Sensory neuron
   Carries message from receptor to spinal cord

3. Spinal cord (Relay neuron / Interneuron)
   Processes the message quickly

4. Motor neuron
   Carries message from spinal cord to muscles

5. Effector (Muscle/Gland)
   Gives response (movement)

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 Example: Touching a Hot Object

Stimulus: Heat from hot pan
Receptor: Skin receptors detect heat/pain
Sensory neuron: Sends impulse to spinal cord
Spinal cord: Immediately sends response signal
Motor neuron: Carries impulse to arm muscles
Effector: Arm muscles contract
Response: Hand is pulled back quickly

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Diagram Line (for exam writing)

Receptor → Sensory neuron → Spinal cord (relay neuron) → Motor neuron → Effector

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 2-line Board Exam Answer

A reflex arc is the route taken by nerve impulses during a reflex action.
Example: When we touch a hot object, the impulse goes from skin → spinal cord → muscles, and the hand is withdrawn immediately.