REVIEW: Osteopathic Reflexes Flashcards
What do dorsal horn neurons respond to?
Both visceral and somatic stimuli
What are the specific layers of the upper layers of the spinal cord?
- Layer 3,4 - mechanoreceptors
- Layers 1, 5 - A delta fast pain fibers
- Layer 2 - small c fibers of slow pain
What types of neurons are included in the lower layers?
- Interneurons
- Motoneuron cell bodies
What layers are afferent fibers located?
End mostly in layers 1 & 5 but lots of overlap
What % of interneurons receive input from both visceral and somatic afferents?
70-80%
May account for visceral pain being so diffuse and poorly located
What is responsible for the activation of somatic muscle activity seen with visceral disturbances?
The overlap of afferents received by interneurons
- Visceral afferents activate sympathetic outflows and skeletal muscle motoneurons (increase tone)
- Reverse is also possible
What affects Visceral/Somatic reflexes?
- Descending influences
- Affect the long-lasting excitability of the outflows by maintaining the reflex
- Sensitization of interneurons acts as an amplifier so outputs are more than expected
- May inhibit somatic and autonomic outflow
What is the result of visceral disturbance?
Reflexively cause activation in the somatic musculature creating somatic dysfunction in the facilitated segment
*contributes to decompensation of homeostasis
What is the result of somatic disturbance?
Reflexively alter visceral function
*contributes to decompensation of homeostasis
What is the somatic component of disease?
MSK palpatory findings may correlate with visceral disturbances
Normalizing MSK component may allow normalization of autonomic outflows resulting in restoration of homeostasis
What is sensitization?
When a stimulus is repeated at a rate of every second or two, response to the stimulus may continue to grow then levels out despite increase of the stimulus
What is habituation?
- Opposite of sensitization
- Process of decreasing response of a neural pathway with a continuous stimulation
- Ubiquitous phenomenon
What is facilitation (facilitated segment concept)?
- Habituation and Sensitization work together to keep a pool of neurons in a state of subthreshold excitation
- Less afferent stimulation is required to trigger discharge of impulses
What causes Facilitation?
May be due to sustained increase in afferent input, aberrant patterns of afferent input, or charges within the affected neurons or their environment
Once established, facilitation can be sustained by normal CNS activity
What is the nociception theory?
- Once a stimulus is strong enough to depolarize nociceptive pathways, impulses travel to cord then branch to multiple sites
- Results in peptide release at motoneuron level in peripheral tissues
- Peptides are important in inflammatory cascade and initiate release of prostaglandins and bradykinins
- This results in lowering nociceptor threshold thus increasing input to cord (balance between habituation and sensitization is disrupted)
What is short term excitability?
- 1-2 seconds of afferent input
- Excitability lasts 90-120 seconds
What is long term sensitization?
- Inputs of several minutes
- Excitability lasts hours
What is fixation?
- 15-40 minutes of afferent input
- Excitability lasts days or weeks
What is permanent excitability?
- Lasts forever
- Death of inhibitory interneurons
What is allostasis?
Our balance of health
- stimulus applied to tissue
- dev’t inflammation
- causes primary afferant sensitization
- results in exaggerated response to noxious stimulus (hyperalgesia)
- secondary hyperalgesia develops (central sensitization)
- change of fxn of viscera and muscle spasm causing asymmetry and altered ROM
- decrease in endogenous descending pathway causing loss of control of protective mechanisms aka allostasis overload
What are the effects of somatovisceral reflexes?
CV - HTN, increased risk of MI
Neuro - Depression, anxiety, memory loss, decreased cognition
Immune - immunosupression, autoimmune
somatosomatic osteopathic reflexes
localized somatic stimuli produce patterns of reflex response in segmentally related somatic structures
somatovisceral osteopathic reflexes
localized somatic stimulation producing patterns of reflex in segmentally related visceral structures
viscerosomatic osteopathic reflexes
localized visceral stimuli producing patterns of reflex response in segmentally related somatic structures
somatic pain referral due to visceral nociceptive stimuli
