all of the nerves and neurons that are not part of the central nervous system.
The nerves and neurons that are not part of the central nervous system form the peripheral nervous system (PNS). The PNS consists of all the nerves and ganglia (clusters of nerve cell bodies) outside of the brain and spinal cord. It comprises two major components: the sensory division and the motor division.
1. Sensory Division: This part of the PNS is responsible for transmitting information from the sensory receptors (such as the skin, muscles, and organs) to the central nervous system. It includes the following types of nerves and neurons:
a) Cranial Nerves: These are the nerves that arise from the brain and mainly serve the head, neck, and face regions.
b) Spinal Nerves: These nerves emerge from the spinal cord and innervate the rest of the body, such as the limbs, trunk, and visceral organs.
c) Sensory Neurons: These specialized neurons are located in sensory ganglia and carry sensory information from the receptors to the central nervous system.
2. Motor Division: This part of the PNS is responsible for transmitting signals from the central nervous system to the muscles and glands in order to initiate actions or responses. It includes the following types of nerves and neurons:
a) Motor Neurons: These neurons are located in the spinal cord and transmit signals to the muscles, controlling voluntary movements and reflexes.
b) Autonomic Nervous System (ANS): The ANS controls involuntary functions and is further divided into the sympathetic and parasympathetic divisions. It regulates activities such as heart rate, digestion, and sweating, among others.
In summary, the nerves and neurons that make up the peripheral nervous system are responsible for relaying information to and from the central nervous system, as well as controlling voluntary and involuntary actions throughout the body.