Heidi A. Everett
Neurons or part of neurons that reside in areas outside of the brain and spinal cord, comprise the peripheral nervous system. Afferent or sensory neurons work to transmit information from the body to the central nervous system. Efferent or motor neurons work to transmit information from the central nervous system to the rest of the body (Hopson, 2006). The sensory information that the afferent neurons send to the central nervous system cause the efferent neurons to send a signal from the central nervous system for muscle cells to contract and glandular cells to secrete hormones (Grabowski, 2000). Another way to help students to distinguish between these two types of neurons is to examine the definition of efferent which means "to carry outward" (Merriam-Webster,
1997). Students should be asked what exit and efferent both have in common. Their responses will be varied but they should make a connection between the connotation of the words and that both words start with the letter e.
The peripheral nervous system is further sub-divided into the autonomic and somatic nervous systems. The autonomic nervous system relays electrical impulses from the central nervous system to internal organs such as the heart (Biggs, 2006). This system deals largely with the involuntary processes of our body such as our breathing and our heart rate. The autonomic system is further sub-divided into the sympathetic and parasympathetic nervous system. The somatic nervous system relays electrical impulses from sensory receptors located externally within the skin and skeletal muscles to the central nervous system and vice versa (Biggs, 2006). The somatic nervous system deals largely with voluntary actions however reflexes also fall under this system as well (Biggs, 2006). A prime example of this would be stepping on a nail and your knee jerking upward before you have yet to process the pain associated with stepping on a nail that went undetected.
