B2 L22 The Nociceptive System and Pain Perception- CNS Flashcards
What are 8 transmitters, chemicals, hormones and ions associated with inflammation, immune system upregulation and/or sensitisation?
- substance P (SP), glutamate, Calcitonin Gene-Related Peptide (CGRP)
- bradykinin (BK)
- histamine (His), Adenosine Tri Phosphate, prostaglandins (PGs)
- Adrenaline
- Nerve growth factor (NGF), Tumor necrosis factor (TNF)
- Cytokines (e.g. interleukin 1), chemokines
- Protons (low pH), and potassium ions.
- enzymes such as cyclo-oxygenase-2 (COX-2). proteinases
What is 1 transmitter associated with blocking nociception?
opioids (endorphins, enkephalins, dynorphins),
What is the Melzack and Wall Gate Theory?
Sensory input and cognitive abilities open and close the gate of pain to modulate the perception of pain.
The possible cross-over between Ab fibres and WDR cells could confuse the brain about whether the stimulus is noxious. (Ab is mechanoreceptor, not nociceptor)
What are the 3 ascending tracts?
- Spinothalamic
- Spinoreticular
- Spinomesencephalic
What is the spinothalamic tract?
What is the spinoreticular tract?
What is the spinomesencephalic tract?
What is Sensory Cortex Plasticity? Give an example.
Nervous system can be very distorted
- Eg. amputees
What is the function of glial cells in DRG, Spinal Cord and Brain?
- The gap in understanding: Every point along the nervous system can be pushed up a slope of sensitisation, but so little on how we can push it back down.
- The reassurance that we can give people, learning to move safely and effectively, gaining sensory input, motor control, physical conditioning, and peace of mind can change cellular functions, changing the expression of DNA.
- Glial cells can grow, change, be activated
- 20 glial cells for every neurons
The gap in understanding: Every point along the nervous system can be pushed up a slope of ________, but so little on how we can push it back down. The reassurance that we can give people, learning to move safely and effectively, gaining sensory input, motor control, physical conditioning, and peace of mind can change _______ functions, changing the expression of DNA.
sensitisation; cellular
Glial cells can _____, _______ and ________. There are ____ glial cells for every neurons
grow; change; be activated; 20
What is a Trigger for sensitization?
Summation of repeated C-fibre inputs results in a progressively more depolarised postsynaptic membrane and removal of the magnesium block from the N-methyl-D-aspartate (NMDA) receptor.
What is a wind up?
A rapid and progressive increase in action potential output from a dorsal horn cell is seen with each stimulus during the course of a train of low frequency C fibre inputs.
What is a Long-term potentiation (LTP)?
Induced by higher frequency stimuli, but the enhanced response outlasts the conditioning stimulus. This mechanism has been implicated in learning and memory in the hippocampus and pain sensitisation in the dorsal horn, as well as increased descending facilitation, +/- phenotypic switch of A beta fibres.
Long-term potentiation (LTP) Induced by ______ (higher/lower) frequency stimuli, but the enhanced response outlasts the ______ stimulus.
higher; conditioning
What is the Melzack – The Neuromatrix Model?
The neuromatrix theory guides us away from the Cartesian concept of pain as a sensation produced by injury, inflammation, or other tissue pathology and toward the concept of pain as a multidimensional experience produced by multiple influences. These influences range from the existing synaptic architecture of the neuromatrix which is determined by genetic and sensory factors to influences from within the body and from other areas in the brain. Genetic influences on synaptic architecture may determine or predispose toward the development of chronic pain syndromes.
The neuromatrix theory guides us away from the Cartesian concept of pain as a sensation produced by _______, _____ or ______ and toward the concept of pain as a ________ experience produced by ______ influences.
injury; inflammation; other tissue pathology; multidimensional; multiple
