The peripheral nervous system (PNS) serves the important function of communication with the central nervous system (CNS). The CNS consists of the brain and spinal cord, while the PNS includes all the nerves that lie outside of the CNS.

Communication with the Central Nervous System:
- One of the main purposes of the peripheral nervous system is to relay information from sensory receptors to the CNS. This information includes signals from the senses such as touch, temperature, pain, and pressure.
- The PNS also transmits motor signals from the CNS to the muscles and glands, allowing for voluntary and involuntary movements and responses.
- Essentially, the PNS acts as a bridge between the external environment and the CNS, allowing for the integration and processing of sensory information and the initiation of appropriate motor responses.

Two Subdivisions of the Peripheral Nervous System:
- The PNS can be further subdivided into the somatic nervous system and the autonomic nervous system.
- The somatic nervous system controls voluntary movements and transmits sensory information to the CNS.
- The autonomic nervous system regulates involuntary functions such as heart rate, digestion, and breathing. It is further divided into the sympathetic and parasympathetic nervous systems, which work together to maintain homeostasis in the body.

Overall Function of the Peripheral Nervous System:
- In summary, the purpose of the peripheral nervous system is to facilitate communication between the external environment and the central nervous system. It plays a crucial role in sensory perception, motor control, and the regulation of bodily functions. Without the PNS, the CNS would be unable to receive information from the outside world or send out commands to the muscles and organs.