REFLEX ACTION
An immediate and involuntary response to a stimulus is called reflex action. Quick pulling of hand just after touching the hot object is a common example of reflex action.
In this example of reflex action shown in temperature of hot object is a stimulus which is received by the cells (thermoreceptors) of the skin. A nerve impulse is created in the sensory neuron present in skin. The nerve impulse is carried by the sensory neuron to the spinal cord. The inter-neuron of the spinal cord transmit the impulse to the motor neuron. The motor neuron carries the impulse to the arm muscles (effectors). The arm muscles contract and the hand is pulled back. The pathway of nerve impulse which complete a reflex action is called reflex arc. It consist of receptor, a sensory neuron, an inter-neuron, a motor neuron and effector.
Reflex arc representing reflex action. Touching a hot object (flame in the example) result in immediate withdrawal of hand through contraction of muscles of arm.
168.797 SRY