Final answer:
The nervous system is split into the central nervous system and the peripheral nervous system, which includes the somatic nervous system responsible for voluntary control and sensation. The somatic system uses efferent fibers to send signals from the CNS to muscles, and afferent fibers to carry sensory information to the CNS. The spinal cord is a key communication path, and damage to it can disrupt these functions.
Step-by-step explanation:
The nervous system is divided into the central nervous system (CNS) and peripheral nervous system (PNS). The somatic nervous system, part of the PNS, is involved in voluntarily controlling skeletal muscles and relaying sensory and motor information to and from the CNS. The motor nerves, also known as efferent fibers, carry impulses from the CNS to muscles, indicating an 'exit' from the CNS, while the sensory or afferent fibers, carry information to the CNS, thus 'arriving' to it. The spinal cord plays a crucial role in this process as a communication superhighway, relaying messages between the body and brain.
Nerves, composed of bundled neurons, contain both afferent and efferent fibers. The PNS also includes ganglia, which are relay points for messages transmitted through nerves. Important to note, sensory receptors such as mechanoreceptors and thermoreceptors help detect stimuli and turn them into nerve impulses; these receptors are integral to the process of sensation in the PNS. Any damage to the spinal cord can result in paralysis due to the interruption of nerve impulse transmission. The PNS can be more susceptible to injury and diseases like diabetes, shingles, or Guillain-Barre syndrome due to being less protected than the CNS.