Describe the path a nerve impulse travels throughout your body from stimulus to response.
The job of the nervous system in an organism such as a human being is intricate and complex. It is designed to receive incoming stimuli from the environment and deliver a calculated and learned response. A stimulus is picked up by sensory nerve cells in the skin and fed along a series of sensory neurons through the network of nerves that is known as the peripheral nervous system (PNS). These are the nerves that radiate out of the spinal cord through the extremities of the body, through the arms and legs. The stimulus then enters the spinal cord, which is housed in the backbone, and is conducted to the brain, where it is interpreted by the brain. This part of the nervous system is known as the central nervous system, or CNS. A response is sent from the brain, the process is reversed, and the response is fed along another set of motor neurons to the set of muscles or organs. Upon receiving the response, the muscles or organs execute the desired response. This all happens very quickly, with no time lost, as some of the responses are designed to preserve the body from harm. Sometimes, the brain is bypassed completely, in a nervous response known as a reflex action. An example of a reflex action would be touching a hot pan on a stove and releasing it quickly so as not to butn your hand.