Final answer:
The peripheral nervous system (PNS) contains all nervous tissue outside the central nervous system (CNS), encompassing nerves of the sensory and motor divisions, which include the sensory-somatic and autonomic systems.
Step-by-step explanation:
The peripheral nervous system (PNS) consists of all the nervous tissue that lies outside the central nervous system (CNS). The PNS includes a vast network of nerves that serve as a communication relay between the CNS and various parts of the body ensuring that sensory information and motor commands are effectively transmitted. Within the PNS are nerves that belong to both the sensory division, which sends information to the CNS, and the motor division, which receives directives from the CNS.
Specifically, the PNS encompasses the sensory-somatic nervous system, which coordinates voluntary movements and conveys sensory information, and the autonomic nervous system that manages involuntary functions such as heartbeat and digestion. It's essential to understand that the brain and spinal cord are not part of the PNS; they comprise the CNS.
Major nerves, such as the sciatic nerve, which is the longest in the human body, are also part of the PNS, running from the lower spinal cord to the toes. Thus, the PNS is fundamentally responsible for connecting the CNS to our limbs and organs, facilitating both voluntary actions and automatic responses in the human nervous system.