Foundations Flashcards
What is fascia?
Fascia is a contractile sensory organ that creates and or envelopes ALL TISSUES and contains PERIPHERAL AFFERENT NOCICEPTORS (PANs). ALL includes: musculature, tendones, bone tissue, organs, vessels, nerves, meninges/dura.
* ALL fascia is histologically similar ie: vascular facia of each artery blends into the muscular or organ fascia that it supplies
What are peripheral afferent nociceptors?
PANS are A delta (quick pain) and C fibers (slow pain) that are generally the first structures involved in pain perception by detecting changes in mechanical or chemicial stimuli, including pro-inflammaotry cytokines that are released by trauma, muscle hypoxia (overuse), and immune responses form viruses or infection.
How can PANS effect multiple spinal segments?
PANS trifurcate in the dorsal horn of the spinal column and thus can impact multiple segments (can span up to 5 segments). The dorsal horn is the first relay center for afferent signals form skin, muscle, and viscera.
How does PANS stimulation cause inflammation?
PANs stimulate the dorsal root ganglia (DRG) to antidromically release neuropeptides (chemical messengers made up of small chains of amino acids that are synthesized and released by neurons) and pro-inflammatory cytokines (loose category of small proteins released by immune system that are important in cell signaling and can have an effect on other cells) causing neurogenic inflammation in peripheral tissue.
Describe Peripheral Motor Reflex (“Muscle Guarding”)
PANs project to the motor neurons of the ventral horn (sends impulses to skeletal muscle) of the spinal cord and can expand pain receptive fields contributing to the development of fascial tender points (TPs) and muscle trigger points ( MTrPs). PANs stimulation of sensitized dorsal horn neurons can directly alter alpha motor neurons creating, muscle guarding reflexes (IE: stimulation of kidney results in reflexive contractions to paravertebral musculature). PANs muscle afferent activation can also activate the gamma (efferent) motor neuron (stretch reflex) system of the same and neighboring musculature.
How does dorsal horn convergence cause referred pain
PANs contact secondary (spinal) neurons that relay signals to the brain, HOWEVER each PAN axon (an axon carries nerve impulses away from the cell body) contacts multiple spinal neurons, and each neuron receives multiple inputs from different PANs (muscle, vascular, visceral, skin). This CONVERGENCE of sensory inputs to the secondary (spinal ) neuron is how referred pain can occur.
What is the sympathetic nervous system (SNA) do when activated?
SNA causes arterial, venous, and/or lymphatic vasoconstriction, limiting ability of these systems to remove inflammatory mediators from the periphery and / or leading to trophic changes. *** subsequent changes in microcirculation can create morphological changes including the destruction of myofilaments and swollen endothelial cells
