Final answer:
The human nervous system is organized into the CNS, which consists of the brain and spinal cord, and the PNS, which extends throughout the body and is subdivided into the autonomic and somatic systems. The CNS processes information, while the PNS acts as a communication relay in both voluntary and involuntary activities.
Step-by-step explanation:
Organization of the Nervous System
The human nervous system is organized into two main parts: the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS is comprised of the brain and spinal cord, serving as the core where all processing and coordination of activities take place. The brain, being the command center, performs various critical functions, including sensation, mobility, emotions, and intellectual processes. The spinal cord acts as a communication highway between the brain and the rest of the body.
The PNS connects the CNS to the limbs and organs, essentially serving as a relay between the brain and spinal cord and the rest of the body. The PNS itself is further divided into the autonomic nervous system (ANS), which controls involuntary body functions such as heart rate and digestion, and the somatic nervous system (SNS), which manages voluntary muscle movements and the relay of sensory information.
The ANS is further subdivided into the sympathetic and parasympathetic systems, which work antagonistically to maintain homeostasis in the body's involuntary functions. The peripheral structures in the PNS, such as nerves and ganglia, are visible as distinct structures unlike the CNS, which is best examined under microscopic conditions.