Final answer:
Spinal cord neurons have receptive fields that receive inputs from multiple tissue types, leading to a perception of pain (allodynia and hyperalgesia) that may not be limited to the point of injury. This is because neurons with free nerve endings integrate various types of stimuli, which can become mislocalized when the nervous system is injured or dysfunctional.
Step-by-step explanation:
The question addresses how spinal cord neurons have receptive fields that encompass inputs from many tissue types. Due to this broad integration of sensory information, conditions like allodynia and hyperalgesia can be perceived even from uninjured or remote tissues. Allodynia refers to a pain response to stimuli that usually do not provoke pain, while hyperalgesia is an exaggerated pain response to painful stimuli. The sensory neurons, specifically those with free nerve endings, are distributed throughout tissues such as the dermis of the skin and are sensitive to a variety of stimuli including chemical, thermal, and mechanical sensations. When the sensory system is compromised due to an injury or dysfunction, the perceived pain may not accurately reflect the source of the stimulus, leading to widespread or incorrectly localized pain sensations.