stem is an extension of the central nervous system and includes 43 nerves containing afferent and efferent fibers. Afferent fibers carry signals to the central nervous system and efferent fibers carry signals away from the central nervous system to the body. The peripheral nervous system also has 31 pairs of spinal nerves and 12 pairs of cranial nerves. These nerves are responsible for the five senses. The 12 cranial nerves located in the brainstem. The skull has holes in the base to allow nerves to travel to parts of the body. The olfactory nerves control the sense of smell. Optic nerves have nerve fibers that transmit information about images. Oculomotor, trochlear, and abducens and nerves contain motor nerves that move the eyeball, eyelid, and change the pupil size. The trigeminal nerves transmit information from the head and face and controls mouth movements. The facial nerves control muscle movements in facial expressions. Vestibulocochlear nerves carries information about body balance from the inner ear and transmit information about sound. Glossopharyngeal nerves provide information about taste. Vagus nerves transmit information from major organs to the brain. The spinal accessory nerves regulate movements of the shoulder and neck muscles. The hypoglossal nerves move the tongue while eating or talking. On both sides of the spinal cord are the spinal nerves, which are divided into two bundles. One is a sensory fiber that detects touch while the other is made up of motor fibers. Sensory fibers carry signals from the skin, muscles, and other parts of the body to the spinal cord. Motor fibers carry signals from the spinal cord to muscles and glands. The sensory fibers enter the spinal cord towards the dorsal root, which is in the back of the spine. The motor fibers exit towards the ventral root, the front side of the spinal cord. Autonomic Nervous SystemThe autonomic nervous system is also known as the involuntary nervous system beca...
