Osteopathic Reflexes Lecture Flashcards
What is a reflex?
relationship between an input stimulus to the body & an output action to either a muscle or secretory organ
What are interneurons?
neurons that take in information from body or viscera & send out that info (stay w/ in brain)
What is found in lower layers of spinal cord gray matter?
interneurons
motorneuron cell bodies
Why do we see a localized pain pattern?
interaction of somatic efferents with visceral & somatic afferents
Basis for activation of somatic muscle activity
visceral afferents activate sympathetic outflows & skeletal muscle motor neurons
Descending influences on reflexes
effect long-lasting excitability of outflows by maintaining the reflex
will either increase, decrease, or sensitize neurons
What produces dysfunction?
visceral disturbances reflexively cause activation in somatic musculature
somatic disturbances can reflexively alter visceral function
What does dysfunction lead to?
loss of health & decompensation of homeostasis
Somatic component of disease
MSK palpatory findings may correlate w/ visceral disturbances
normalization of autonomic outflows results in restoration of homeostasis
Facilitated segment concept
afferent input comes into cord interacting w/ interneuron chains
interneurons can act as amplifiers or inhibitors
Habituation
process of decreasing response of neural pathway w/ continuous stimulation
Nociception Theory
Habituation & sensitization
2 processes exist together to help maintain a homeostasis btwn over-reaction & under-reaction to a stimulus
What happens in facilitation?
less afferent stimulation required to trigger discharge of impulses (go off no matter what)
Nociception steps
once stimulus is strong enough to depolarize nociceptive pathways, impulses travel to spinal cord & branch to multiple sites
release of peptides @ motorneuron level in peripheral tissues
peptides involved in inflammatory cascade & initiate release of prostaglandins
chemical soup spreads in tissues
What does NOT have nociceptors?
brain or hyaline cartilage
What is the result of the chemical soup of proteins?
lowers nociceptor threshold which increases input to spinal cord
inflammation results in larger than normal motor outputs to autonomics & somatic systems
Outline steps that increase sensitivity of neurons
Short term excitability
Long term sensitization (minutes to hours)
Fixation (longer output)
Permanent excitatbility (death of inhibitory interneurons)
Facilitated Segment Concept
excitable areas assoc w/ injury & disease
low threshold spinal reflexes represent pathways in hyper-excited state
relates to skeletal muscle & sympathetic nervous system
Allostasis
long term neural effect of segmental facilitation on what your body wants to maintain
stimulus to tissues
develop chemical soup of inflammation
causes primary afferent sensitization
results in hyperalgesia
Hyperalgesia
exaggerated response to noxious stimulus (so do not engage that stimulus again)
Allostasis in spinal cord
Dorsal horn: lose inhibitory neuron function (lots of Ca2+)
Ventral horn: outflows to soma & autonomics (muscle spasms & affects visceral fxn)
Allostasis in brainstem
arousal system leads to loss of control of protective mechanisms=allostasis overload
Somatosomatic reflex
localized somatic stimuli producing patterns of reflex response in segmentally related somatic structures
Somatovisceral reflex
localized somatic stimulation producing patterns of reflex response in segmentally related visceral structures
ex: somaticocardiac, somatogastic, somatoadrenal
