peripheral nervous system PNS Flashcards
1
Q
PNS
A
- nerve that originates in brain/SC and end peripherally
2
Q
divisions of NS
A
3
Q
cutaneous sensory end-organ receptors
A
- thermoreceptors: temperature sensory receptor
- nociceptors: painful stimuli sensor
- chemoreceptors: spinal nerve cells that detect changes in chemical comp of blood and send info to brain to regulat CV and resp function
- photoreceptors: in retina, visual phototransduction
- mechanoreceptors: repond to mech stimu like touch or sound ->
- merkel’s disc: light touch in fingers and lips
- ruffini’s corpuscle: touch, low-frequency vibration flutter
- pacinian corpuscle: pressure and vibration
- meissner’s corpuscle: fine, discriminative touch and vibration
- muscle spindle: stretch detectors
- free nerve ending: sensitive to painful stimuli, hot and cold, light touch
- golgi tendon organ: proprioceptors in tendon adjacent to myotendinous junction, detect change in muscle length, posture, motion
4
Q
endoneurium
A
innermost covering of peripheral nerve that surrounds each individ axon
5
Q
epineurium
A
outermost covering of peripheral nerve that surrounds entire nerve and provides buffer for peripheral nerve
6
Q
motor unit
A
single motor neuron and all muscle fibers it innervates
7
Q
perineurium
A
middle layer of covering surrounding peripheral nerve that envelops fascicles or groups of axons and maintains blood-nerve barrier
8
Q
saltatory conduction
A
AP moving along axon in jumping fashion from node to node (nodes of Ranvier), decreases use of Na/K pumps and increases speed of conduction
9
Q
classification of peripheral nerve fibers
A
- A fibers: large and myelinated - light touch, pressure, vibration
- B fibers: medium and myelinated - reasonably fast, gross touch; preganglionic fibers of ANS
- C fibers: small and un/poorly myelinated so slowed conduction rate, pain, temperature, touch; postganglionic fibers of SMS
10
Q
subsetss of A fibers
A
- alpha: alpha motor neurons, muscle spindle, golgi tendon organs, touch
- beta: touch, kinesthesia, muscle spindle secondary endings
- gamma: touch, pressure, gamma motor neurons
- delta: pain, touch, pressure, temperature
11
Q
dermatomes
A
12
Q
UE myotomes
A
- C4 - shoulder elevation
- C5 - shoulder abd
- C6 - elbow flexion, wrist ext
- C7 - elbow ext, wrist flexion
- C8 - thumb ext, finger flexion
- T1 - finger abd/add
13
Q
LE myotomes
A
- L1-2: hip flexion
- L3: knee ext
- L4: ankle DF and inv
- L5: great toe ext
- L5-S1: ankle PF, hip ext
- S2: ankle PF and EV, knee flexion
14
Q
superficial reflexes
A
response to stimulation fo receptors within the skin
- different from DTR bc sensory signal must reach SC and ascend to brain
- motor compopnent must also descend SC to reach motor nueons for polysynaptic reflex
- graded as present or absent, or large difference between L and R
15
Q
deep tendon reflex
A
- elicit muscle contraction when tendon stimulated d/t reflex arc involving spinal and or brainstem segment that innervates specific muscle
- graded 0 (absent), 1+ (diminished), 2+ (active normal), 3+ (brisk, exaggerated), 4+ (hyperactive)
- C5: biceps
- C6: brachioradialis
- C7: tricep
- L4: patellar
- S1: achilles
16
Q
most common etiology surrounding absent reflexes
A
- peripheral neuropathy
- can be associated with DM, etoh, pernicious anemia, cancer, toxins
17
Q
superficial sensation screen
A
- temperature
- light touch
- pain
18
Q
deep sensation screening
A
- proprioceptive
- kinesthesia
- vibration
19
Q
cortical sensation screen
A
- bilateral simultaneous stimulation
- stereognosis
- two-point discrimination
- barognosis
- localization of touch
20
Q
barognosis
A
receive weight of different objects in hand
21
Q
deep pain sensation
A
squeeze forearm or calf muscle
22
Q
graphesthesia
A
ID a number or letters drawn on skin without usual input
23
Q
kinesthesia
A
ID direction and extent of movement of a joint or body part
24
Q
stereognosis
A
ID object without sight
25
allodynia
sensation of pain in response to stimulus that would normally not cause pain
26
analgesia
absence of pain while remaining conscious
27
causalgia
constant, burning hyperesthesia and hyperalgesia that develops after peripheral nerve injury
28
dysesthesia
distortion of any of the sense, esp touch
29
hyperesthesia
heightened sensation
30
hyperpathia
extreme exaggerated response to pain
31
hypesthesia
diminished sensation of touch
32
neuralgia
severe and multiple shock-like pain that radiate from a specific nerve distribution
33
pallanesthesia
loss of vibration sense
34
paresthesia
abnormal sensations like tingling, pins, and needles or burning sensations
35
double crush syndrome
existence of 2 separate lesions along same nerve that creates more severe symptoms than if only one lesion existed
36
mononeuropathy
isolated nerve lesion - associated with conditions of trauma and entrapment
37
neuroma
abnormal growth of nerve cells - associated with vasculitis, AIDs, amyloidosis
38
peripheral neuropathy
impairment or dysfunction of PN - associated with DM, trauma, etoh
39
polyneuropathy
diffuse nerve dysfunction that is symmetrical, typically secondary to pathology and not trauma - GBS, peripheral neuropathy, use of neurotoxic drugs, HIV
40
wallernia degeneration
degeneration that occurs distally - specifically to myelin sheath and axon
41
neurapraxia
- mildest form of peripheral axon injury
- myelination dysfunction but axonal continuity preserved
- recovery in 4-6 weeks
- pressure injuries most common
42
axonotomesis
- more severe peripheral nerve injury
- reversible injury to damaged fibers as they maintain anatomical relationship
- recovery 1 mm/day, can seem spontaneous
- d/t traction, compression, crush injuries
43
neurotomesis
- most severe grade of peripheral nerve injury
- irreversible, all motor and sensory loss distal to lesion is permanently impaired
- can have some recovery with surgical reattachment - 1 mm/day, sensory recovers sooner than motor
44
anterior horn cell pathology
| in PNS
- amyotrophic lateral sclerosis, poliomyelitis
- sensory component intact
- motor weakness and atrophy
- fasciculations
- decreased DTRs
45
muscle pathology
| in PNS
- muscular dystrophy
- sensory component intact
- motor weakness
- fasciculations rare
- normal or decreased DTRs
46
neuromuscular junction pathology
| in PNS
- myasthenia gravis
- sensory component intact
- motor fatigue greater than actual weakness
- normal DTRs
47
peripheral nerve (mononeuropathy) pathology
| in PNS
- trauma
- sensory loss along nerve root
- motor weakness and atrophy in peripheral distribution
- may have fasciculations
48
spinal roots and nerves pathology
| in PNS
- herniated disc
- sensory component will have corresponding dermatomal deficits
- motor weakness in innervated pattern
- may have fasciculations
- decreased DTRs
49
UMN vs LMN disease
- **UMN**
- reflexes: hyperactive
- atrophy: mild from disuse
- fasciculations: absent
- tone: hypertonic
- **LMN**
- reflexes: diminished to absent
- atrophy: present
- fasciculations: present
- tone: hypotonic to flaccid
50
hypokinesia
- apraxia: difficulty with skilled movement even if you have ability/desire to do them
- rigidity
- bradykinesia: slowness of movement
51
hyperkinesia
- ataxia
- athetosis
- chorea
- tics
- tremors
- dysmetria
- dystonia
52
athetosis
- movement disorder of slow, twisting, writhing movement large in amplitude
- in trunk, mouth, tongue, extremities
- if movements are brief, merges with chorea -> choreoathetosis
- common in CP secondary to basal ganglia pathology
53
chorea
- form of hyperkinesia, presents with brief and irregular contractions that are rapid
- secondary to damage to caudate nucleus
- common with huntington's
54
dystonia
- syndrome of sustained muscle contractions frequently causing twisting, abnormal postures, repetitive movements
- involuntary movements accentuated during volitional movements
- presentation varies
- common with PD, CP, encephalitis
55
tic
- sudden brief, repetitive coordinated movement usually at irregular intervals
- simple or complex
- like tourretts
56
tremor
- involuntary, rhythmic, oscillatory movements -- 3 groups
- reting: tremor at resting that may or may not disappear with movement, can increased with mental stress, pill-rolling in PD
- postural: during voluntary contraction to maintain a posture, seen in hyperthyroidism, fatigue or anxiety
- intention (kinetic): absent at rest but observable with activity, increase as target approaches, in MS, indicative of cerebellum and its efferent pathways
57
akinesia
inability to initiate movement, commonly seen in PD
58
asthenia
generalized weakness, typically secondary to cerebellar pathology
59
ataxia
inability to perform coordinated movement
60
athetosis
condition with involuntary movements combined with instability of posture, peripheral movements occur without central stability
61
bradykinesia
movement that is very slow
62
chorea
movements that are sudden, random, involuntary
63
clasp-knife response
form of resistance in ROM of a hypertonic joint, greatest resistance at initiation of ROM that lessens with movement through ROM
64
cogwheel rigidity
rigidity where resistance to movement has a phasic quality, often in PD
65
dysdiadochokinesia
inability to perform rapidly alternating movements
66
dysmetria
inability to control ROM and force of muscular activity
67
dystonia
closely related to athetosis but larger axial muscles involves
68
hemiballism
involuntary and violent movement of large body part
69
lead pipe rigidity
rigidity where there is uniform and constant resistance to ROM, associated with lesions of basal ganglia
70
modified ashworth scale
- grading for spasticity - measures amount of resistance to passive stretch
- 0 - no increase in muscle tone
- 1 - slight increase in tone, catch and release or minimal resistance at end ROM
- 1+ - slight increase, catch followed by minimal resistance for less than half of ROM
- 2 - more marked increase in tone through most of ROM but affected part(s) move easily
- 3 - considerable increase in tone, passive movement difficult
- 4 - affected part(s) rigid in flexion or extension
