residency neuro Flashcards
What steps does the nervous system take in response to type IV mechanorecptor depolarization?
- mechanical or alpha motor neuron
- cognitive or perceptual response
- local Sympathetic response
- Gamma motor or tonic guarding
What is perikaryon?
cytoplasm of the nerve cells nucleus
What are the small swellings at the end of the axon know as?
terminal buttons
What structures surround the axon of the nerve>
Schwan cells
what is the endonural fluid pressure
- the interstial fluid pressure inside the neural fascicle
2. slightly greater than the pressure in the surround tissues
What is the normal endoneurol fluid pressure for the median nerve?
2.5 mmHg
What are nerve roots more prone to entrapment than peripheral nerves?
- they lack perineurium and have poorly developed epineurium
- the perineurium helps to resist compression forces
What layer of connective tissue surrounding nerves helps to resist compression?
perineurium
What is the difference between simple and complex receptors?
- simple-branched or unbranched free nerve endings responsible for cutaneous, temperature and pain
- complex-associated with non neural tissues to complete their function such as a barorecptor or corpuscle
What is the cytoplasm of the nerve cell nucleus call?
Perikaryon
What is the function of the muscle spindle receptor?
responsible for the regulation of muscle tone via the muscle stretch reflex
How is the sensitivity of the muscle spindle regulated?
- intrafusal muscle tone regulates the tension or sensitivity of the receptor
- the gamma motor neuron projectes the efferent signal from the spinal cord to regulate the tone of the muscle spine
What is the purpose of the muscle spindle?
to regulate the tone of the muscle
What are the type II afferents of the muscle spindle?
- flower spray
- mylinated
- smallest of the spindle afferents
- attach directly to the striated portion of the fusiform muscle
- sense static activity
What happens when the muscle spindle is stretched?
- stretch causes tension on the nuclear bag or chain intrafusal muscle
- triggers the annulo spiral or flower spray afferents
- reflexive alpha motor or extrafuscle muscle contraction
What is the dual nociceptive system
- intrinsic- plexus of unmylinated nerve endings through out the tissues
- perivascular- nociceptive receptor system within blood vessels
What is the perivascular nociceptive system?
- all blood vessels, except skull capillaries, contain nociceptive free nerve endings
- activated by by extreme changes in vessel wall diameter
What is the pathway of the recurrent nerve?
- branches off or into the ventral rami since it is afferent only at this point
- picks up sympathetic efferents
- travels into/out the foramen
- afferents innervate the disc, anterior dura and PLL
What are the apical and basilar nuclei of the spinal cord?
- apical is lamina I and II of the dorsal horn
2. basilar is lamina V and VI of the dorsal horn
What nuclei in the dorsal horn play a role in the pain response?
- apical or lamina I and II
2. basilar or lamina V and VI
How do you stop peripherally regulated pain?
remove the primary cause of the type IV depolarization
At what point will a type IV mechanoreceptor stop firing
- they are non adapting so you must remove the stimulus
- deformity less than 3%
- thermal level below 44.8 C or 112 F
- normalize chemical levels