Nervous system suffixes chapter 12Presentation Transcript
NERVOUS SYSTEM SUFFIXESCHAPTER12 ALGESIA ATAXIA HANNINGTON M MUWANGA MEDICAL TERMINOLOGY SUMMER 2011
ALGESIA from the Greek word algesis, is the sensitivity to pain. The term is sometimesused to refer to hyperalgesia (an extreme sensitivity). The most commonly used terms in the pain research are hyperalgesia and allodynia. The word hyperalgesia means an increased response to apainful stimulus. The word allodynia means a painful response to a normally innocuousstimulus.
HYPERALGESIA This involves a noxious stimulus, it just becomes morepainful when hyperalgesia is present. The noxious stimulus activates nociceptors in the periphery that then send the signal onto the spinal cord. Hyperalgesia involves anamplification of the pain signal. This amplification can occur in the periphery (e.g. the nociceptor is sensitized by an irritant, by inflammation or by disease) or in the spinal cord(via an amplification of synaptic transmission between the nociceptor and the dorsal hornneuron that sends the signal to the brain) or in both locations.
ALLODYNIA Involves a noxious response to an innocuous stimulus .Because the stimulus is innocuous, and generally of the mechanical variety, it could be carried by rapidly adapting mechanotransducers or by sensitized nociceptors. While there is evidence that the information can becarried by sensitized nociceptors, current understanding ofallodynia suggests that nociceptor mechanical thresholds do not change enough for them to carry information concerning light touch, brush or gentle vibration in conditions whereallodynia is present. Rather, it appears that rapidly adapting mechanotransducers continue to be the sole carrier of this information in conditions whereallodynia is present.
Hyperalgesia is an increased response to a noxious stimulus. It is caused by sensitizationof peripheral nociceptors and/or by sensitization of central neurons that carry nociceptiveinformation. Allodynia is a painful response to a non-painful stimuli. It is caused by a change in thedorsal horn of the spinal cord that gives non-noxious sensory information access to thenociceptive system causing innocuous stimuli to be perceived as painful
ATAXIA Ataxia describes a lack of muscle coordination during voluntary movements, such as walking or picking up objects. A sign of an underlying condition, ataxia can affect your movements, your speech, your eye movements and your ability to swallow. Persistent ataxia usually results from damage to your cerebellum — the part of your brain that controls muscle coordination. Many conditions may cause ataxia, including alcohol abuse, stroke, tumor, cerebral palsy and multiple sclerosis. It's also possible to inherit a defective gene that may cause one of many ataxia variants
conditions to cause ataxia alcohol abuse stroke Tumor cerebral palsy multiple sclerosis It's also possible to inherit a defective gene that may cause one of many ataxia variants.
Treatment for ataxia This depends on the underlying cause. Adaptive devices, such as walkers or canes, might help you maintain your independence despite your ataxia. You may also benefit from physical therapy, occupational therapy and speech therapy.
Symptoms Poor coordination Unsteady walk and a tendency to stumble Difficulty with fine-motor tasks, such as eating, writing or buttoning a shirt Change in speech Involuntary back-and-forth eye movements Difficulty swallowing