Chapter 4 - Peripheral nerves

Abstract

This chapter discusses how the brain and spinal cord are connected to the body by the cranial and spinal nerves that carry sensory information to the central nervous system. In the spinal cord and hindbrain, the motor and sensory components can be further divided into somatic and visceral groups. The somatic groups supply voluntary muscles and receive sensation from skin or vibration receptors. The spinal cord is connected to the body by about thirty-two pairs of spinal nerves. The pairs of spinal nerves arise from the spinal cord and leave the vertebral column through spaces between the vertebrae. The brain is connected to the parts of the head and neck by twelve pairs of nerves, called the cranial nerves. Like the spinal nerves, the cranial nerves have motor and sensory components. The autonomic nervous system consists of two major functional divisions—parasympathetic and sympathetic—each with characteristic anatomy and functions. The autonomic nervous system includes the motor neurons that control the physiology of the viscera, sweat glands, and blood vessels.