Final answer:
Spinal cord injuries result in sensory and motor deficits below the injury level, causing pathophysiological changes that include inflammation, scar tissue formation, and interruption of nerve impulses, leading to paralysis. The location of the spinal injury dictates the extent of paralysis, and the central nervous system's limited ability to regenerate hinder recovery.
Step-by-step explanation:
Spinal Cord Injuries and Pathophysiology
Spinal cord injuries (SCIs) are characterized by damage to the spinal cord which impacts the neurological functions below the site of injury. Due to the arrangement of sensory and motor regions within the spinal cord, damage can lead to sensory and motor deficits. The pathophysiological changes following an SCI include immediate mechanical disruption of axons and later, a cascade of vascular, cellular, and biochemical events causing further damage. Inflammation and apoptosis exacerbate the situation, leading to more extensive neuronal death and scarring, inhibiting any nerve regeneration. Paralysis occurs as a result, which is largely dependent on the injury's location.
The spinal cord is composed of white matter and gray matter. White matter contains myelinated axons which relay information to and from the brain whereas gray matter houses neuronal cell bodies and modulates motor and sensory information. If damage occurs high on the spinal cord, such as the neck, it may cause quadriplegia—paralysis below the neck. Injuries lower on the spinal cord may cause paraplegia—paralysis of the legs.
Following an SCI, complex cellular mechanisms are initiated that could be detrimental to the recovery process. While nerves in the peripheral nervous system can regrow to an extent, the central nervous system (CNS), which includes the spinal cord, does not regenerate easily. Experiments have shown that while nerve fibers attempt to regrow, factors within the CNS create an environment that is not conducive to repair. Aside from physical barriers such as scar tissue, there are also chemical inhibitors of growth that are present in the CNS.
Treatments often focus on minimizing further damage, managing inflammation, and promoting any potential neuroplasticity. Emerging research, including stem cell therapy, aims to find ways to promote regeneration and functional recovery of the spinal cord.