Question

What is reflex action? Describe the steps involved in a reflex action? (CAC1)

Answer 1

A reflex action is an unconscious, involuntary and instantaneous movement or response due to a stimuli.

The reflex action is an unconscious action as it does not require the involvement of the brain rather the use of nervous pathways known as reflex arcs. 

An example of a reflex action is the instant drawing back of the arm from a hot object. 

Here is how a reflex action takes place:

Stimulus → receptor → sensory neurone → relay neurone → motor neurone → effector

A stimulus is the agent causing neurotransmission. Stimulus evokes the functional reaction of part of body or organ that is required.

An effector is any part of the body that produces the response. Examples of effectors are muscles that move the arm and glands that produce hormones. 

This is what happens:

Receptor detects a stimulus(change in the environment)------>Sensory neurone sends signal to relay neuron---->Motor neuron sends signal to effector---->Effector produces the desired response.

Answer 2

The reflex action is an unconscious action as it does not require the involvement of the brain rather the use of nervous pathways known as reflex arcs.

The steps involved in reflex action are:

1)Receptor detects a stimulus(change in the environment)

2)Sensory neurone sends signal to relay neuron

3)Motor neuron sends signal to effector

4)Effector produces the desired response.