What Is the Peripheral Nervous System and What Does It Do?

The peripheral nervous system includes the nerves connecting the brain and spinal cord (which is the central nervous system, or CNS) and allows communication between the brain and the body.

The peripheral nervous system refers to the nerves that branch out from the brain and spinal cord (which is the central nervous system, or CNS). The peripheral nerves communicate between the brain and the body.   

Two Parts of the Peripheral Nervous System

There are two parts to the peripheral nervous system:

• Somatic nervous system
  • Made up of nerves that relay information from the skin and muscles
  • Involved in conscious activities
• Autonomic nervous system
  • Made up of nerves that connect the brain to organs such as the heart, stomach, intestines, and glands
  • Functions automatically and unconsciously 
  • Involved in heart rate, breathing rate, blood pressure, body temperature, and other activities of internal organs that work together to maintain internal stability 

Three Types of Peripheral Nerves

There are three types of peripheral nerves found within the two parts of the peripheral nervous system:

• Sensory nerves
  • Also called afferent nerves
  • Connects the central nervous system to the skin and permits the sensations of touch, pain, temperature, and other sensations
• Autonomic nerves
  • Responsible for involuntary functions such as blood pressure, digestion, and heart rate
  • Comprised of the sympathetic and parasympathetic nervous systems
    • Sympathetic nervous system
      • Connects internal organs to the brain
      • Prepares the body for stress with increased heart rate, increased blood flow to muscles, and decreased blood flow to the skin
  • Parasympathetic nervous system
    • Increases digestive secretions and reduces heartbeat
• Motor nerves
  • Sends signals from the brain and spinal cord to the muscles
  • Involved in muscle control and responsible for activities such as body to walking, catching a ball, and moving the fingers