Reflex arc is the pathway which is taken by nerve impulse to accomplish reflex action. Reflex action is the result of the coordination of the spinal cord and peripheral nervous system. This action does not involve the brain. The pathway in which impulses travel during the reflex action is called a reflex arc.

What will you do if someone pricks your hand with a needle? Elucidate the pathway of response with a neat labelled diagram. Enable Ginger Cannot connect to Ginger Check your internet connection or reload the browser Disable in this text field Edit Edit in Ginger Edit in Ginger ×

If someone pricks our hand with a needle, we immediately withdraw our hand. Here the skin is the receptor and it receives the stimulus, that is the pain. This stimulus in turn triggers an impulse in a sensory neuron. The sensory neuron transmits the message to the spinal cord. The spinal cord interprets the stimulus and the impulse is passed on to the relay neuron which in turn transmits it to a motor neuron. The motor neuron carries command from the spinal cord to our arm. The muscle in our arm contracts, and we withdraw our hand immediately.

Classify neurons based on its structure. Enable Ginger Cannot connect to Ginger Check your internet connection or reload the browser Disable in this text field Edit Edit in Ginger Edit in Ginger ×

Based on structure, the neurons are classified as the following types- i) Unipolar neurons- In this only one nerve process arises from the cyton. It acts as both axon and dendron. These are found in early embryos but not in adults. ii) Bipolar neurons- In this, the cyton gives rise to two nerve processes. One acts as an axon while another as a dendron. These are found in the retina of the eye and olfactory epithelium of nasal chambers. iii) Multipolar neurons- Here the cyton gives rise to many dendrons and an axon. These are found in the cerebral cortex of the brain.