Wednesday, July 16, 2025

WHAT IS REFLEX ACTION? (CBSE 10TH BIOLOGY)

 

Reflex action is an automatic, quick, and involuntary response to a stimulus that does not involve the conscious part of the brain.


  • Reflex actions are controlled by the spinal cord, not the brain.

  • They help protect the body from immediate harm or danger.

  • These actions happen without thinking, which makes them fast and efficient.

  • Example of Reflex Action:

Touching a hot object:

  • When you accidentally touch a hot pan, you immediately withdraw your hand.

  • This response happens without waiting for the brain to decide.

  • The sensory nerves carry the message to the spinal cord → spinal cord sends an immediate signal to muscles → hand pulls back.

Pathway of Reflex Action (Reflex Arc):

Stimulus (heat)
Receptor (skin)
Sensory neuron
Spinal cord (control center)
Motor neuron
Effector (muscles)
Response (pulling hand away)

  • Common Reflexes:
  • Blinking when something comes close to your eyes

  • Sneezing due to dust
  • Knee-jerk reaction at the doctor’s office

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