what is reflex action??? give five examples

An automatic action or response provoked by a stimulus is known as a reflex action.

Reflex arc
When we accidentally touch a hot object, we withdraw our hands immediately without thinking. If we do not do this, our hands will burn.

The sensory nerves detect the heat. They are connected to the nerves, which move the muscles of the hand. Such a connection of detecting the signal from the nerves (input), and responding to it immediately (output) is called a reflex arc. In other words it is the pathway along which nerve impulse travels during the reflex action.

A reflex arc makes instant and automatic responses possible. It connects the input nerve and output nerve, and meets in a bundle in the spinal chord. In fact, nerves from all over the body meet in a bundle in the spinal cord, on their way to the brain. Therefore, the information input reaches the brain.

The reflex arc consists of five distinct parts and these are:

1. Receptor: It includes sense organs that receive stimulus.

2. Sensory neuron: It conducts the nerve impulse from receptor to the spinal cord or brain.

3. Association neuron: It helps to transmit nerve impulse from sensory neuron to motor neuron.

4. Motor neuron: It transmits nerve impulse to the effector organs like muscles or glands.

5. Effector: It includes muscles or glands where action takes place in response to stimulus.