What are reflex actions? Give two examples. Explain a reflex arc.

Reflex action - Sudden action in response to something in the environment is called reflex action.

For example- When we touch a hot object, we withdraw our hand immediately without thinking.

Closing of eyes, when bright light is focused show sudden response and do not involve any thinking. These are examples of reflex action.

The path through which signals are transmitted from a receptor to a muscle or a gland is called reflex arc. The following flow chart shows the flow of signal in a reflex arc.

Receptor ⇨ Sensory Neuron ⇨ Relay neuron ⇨ Motor neuron ⇨ Effector (muscle)

Stimulus received by the sensory receptors. The sensory neurons pick signals from the receptor and send them to the relay neuron. The relay neuron is present in the spinal cord. Impulses travels from the spinal cord to the motor neuron. The end of motor neuron connects effector organ or muscles which produce response.