What is Reflex Action? Explanation with Diagram - Science MCQ

What is Reflex Action? Explanation with Diagram

Introduction

Reflex action is an automatic, rapid response to a stimulus that occurs without conscious thought. It serves as a defense mechanism in humans and animals. For example, withdrawing your hand immediately after touching a hot object is a reflex action.

Definition of Reflex Action

A reflex action is a sudden, involuntary response to a stimulus. This type of response happens through a special pathway called the reflex arc. It does not involve the brain directly, which allows for a quicker response.

Reflex Arc Diagram (Textual Representation)

Stimulus (Hot object) 
→ Receptor (Skin) 
→ Sensory Neuron 
→ Spinal Cord (Relay Neuron) 
→ Motor Neuron 
→ Effector (Muscle) 
→ Response (Hand pulls away)

Detailed Explanation

• Receptor: Skin detects the hot object.
• Sensory Neuron: Sends the signal to the spinal cord.
• Relay Neuron: Processes the information in the spinal cord.
• Motor Neuron: Sends the response signal to the muscles.
• Effector: Muscle reacts and pulls the hand back.

Note

- Reflex actions occur without the involvement of the brain.
- They are controlled by the spinal cord.
- The neurotransmitter acetylcholine helps in transmitting signals between neurons.
- Reflexes help protect us from immediate harm.