Shared Flashcard Set

Details

Diseases of the Motor Unit
Diseases of the Motor Unit
77
Anatomy
Graduate
03/17/2015

Additional Anatomy Flashcards

 


 

Cards

Term
motor neuron and the group of muscle fibers it innervates
Definition
motor unit
Term
most diseaes of the motor unit cause what
Definition
weakness and wasting of the skeletal muscles
Term
what are the components of the motor unit that could be affected by disease? (4)
Definition
cell body, axon, neuromuscular junction, muscle fibers it innervates
Term
when a peripheral nerve is cut what happens to the muscles innervated by that nerve immediately
Definition
paralyzed
Term
when a peripheral nerve is cut what happens to the muscles it innervated later?
Definition
progressively atrophy
Term
when a peripheral nerve is cut what happens to DTRs
Definition
lost immediately
Term
when a peripheral nerve is cut what happens to sensatoin
Definition
sensation to the area innervated by the nerve is lost
Term
when a peripheral nerve is cut it is similar to what type of disease?
Definition
neurogenic, effects appear more slowly
Term
main symptoms of myopathic diseases are due to what
Definition
weakness of skeletal muscle
Term
myopathic diseases include other less common symptoms such as (3)
Definition
myotonia, myalgia, cramps
Term
myotonia
Definition
inability of the muscle to relax
Term
myalgia
Definition
pain
Term
muscular dystrophies are what kind of disease
Definition
myopathies
Term
inherited diseases, symptoms caused by weakness which become progressive more severe over time, histological signs of degeneration and regeneration
Definition
muscular dystrophies
Term
classificiation and differential diagnosis of neurogenic vs myopathic diseases includes what
Definition
clinical and laboratory criteria
Term
distal limb weakness most often indicates what disorder?
Definition
neurogenic
Term
proximal limb weakness usually indicates what disorder
Definition
myopathy
Term
fasciculations are reliable signs as they are only found in what disease
Definition
neurogenic diseases
Term
visible twitches of muscle that can be as flickers under the skin
Definition
fasciculation
Term
fasciculations result from what?
Definition
involuntary but synchronous contractions of all muscle fibers in a motor unit
Term
fasciculations are characteristic of what?
Definition
slowly progressive disease of the motor neuron
Term
fasciculations are rarely seen in what
Definition
peripheral neuropathies
Term
fibrillations arise from what
Definition
spontaneous activity within single muscle fibers
Term
what spontaneous activity of muscle fibers can only be detected by EMG
Definition
fibrillations
Term
high sarcoplasmic enzyme presence in serum is indicative of what type of disease
Definition
myopathic
Term
enzyme activity most commonly used for diagnosis myopathy is what
Definition
Creatine Kinase
Term
what are the 3 specific measurements examined by an EMG
Definition
spontaneous activity at rest, number of motor units under voluntary control, duration and amplitude of AP's in each motor unit
Term
in normal muscle at rest, what should the EMG read at the end plate
Definition
no activity
Term
in neurogenic disease, what does the resting muscles activity look like
Definition
spontaneously active
Term
why may the amplitude and duration of an individual motor unit potentials increase despite neurogenic disease
Definition
remaining axons give off small branches that innervate denervated muscle fibers
Term
in which disease is there no muscle activity at rest and no change in the number of motor units firing during a contraction
Definition
myopathic
Term
in a myopathic disease what happens to the duration and amplitude of a contraction
Definition
shorter duration and smaller in amplitude due to fewer surviving muscle fibers
Term
what are the predominant metabolic enzymes present in type I
Definition
oxidative
Term
what are teh predominant metabolic enzymes present in type II
Definition
anaerobic/glycolytic
Term
the histochemical type of the muscle is determined by what
Definition
the neuron
Term
in chronic neurogenic diseases, what happens to the muscle innervated by a dying motor neuron
Definition
becomes atrophic and some muscle fibers disappear
Term
what happens to denervated muscle fibers when their neurons die
Definition
innervate by axons of surviving neurons
Term
due to reinnervation by the surviving neurons what can happen to the muscle fiber
Definition
its histochemical type can change
Term
best known disorder of motor neurons
Definition
ALS
Term
symptoms of ALS usually start with what
Definition
painless weakess of the arms or legs
Term
typical patient of ALS
Definition
man in his 60s
Term
ALS weakness is associated with what
Definition
wasting of the small muscles of the hands and feet and fasciculations of the muscles of the arm and forearm
Term
ALS exhibits signs of lower motor neuron disease, but is often paradoxically associated with what symptom
Definition
hyperreflexia (characteristic of upper motor neuron disease)
Term
dysarthria
Definition
difficuluty speaking
Term
dysphagia
Definition
difficulty swallowing
Term
a variant of motor neuron disease with symptoms being restricted to muscles innervated by cranial nerves would result in what symptoms
Definition
dysarthria, dysphagia
Term
when cranial symptoms of motor neuron disease occur alone, the syndrome is called what
Definition
progressive bulbar palsy
Term
if only lower motor neurons are involved, what is the syndrome called
Definition
progressive spinal muscular atrophy
Term
spinal muscular atrophy is characterized by what (4)
Definition
weakness, wasting, loss of reflexes, fasciculation
Term
Disorders of peripheral nerves usually affect which functions
Definition
motor and sensory
Term
patients with neuropathies report pins and needles sensation without an external sensory stimulus, this is called what
Definition
parethesias
Term
patients with paresethesia usually have impaired perception of what sensations
Definition
pain and temperature
Term
patients with paresthesias may or may not have this sense be involved
Definition
touch
Term
in neuropathies, this sensation may be lost with loss of cutaneous sensation
Definition
proprioceptive sensations
Term
sensory disordres are usually more prominent where? and are called what?
Definition
distally, glove and stocking pattern
Term
peripheral neuropathy is first manifested by weakness predominantly where in acute cases
Definition
proximal
Term
peripheral neuropathy is first manifested by weakness predominantly where in chronic disorders
Definition
distal
Term
what happens to tendon reflexes in peripheral neuropathies
Definition
usually depressed or lost
Term
best known acute neuropathy
Definition
guillan-barre syndrome
Term
guillan-barre syndrome usually follows what
Definition
respiratory infection
Term
disorder attributed to an autoimmune attack on peripheral nerves by circulating antibodies
Definition
guillan-barre syndrome
Term
how is guillan-barre syndrome treated
Definition
plasmapheresis
Term
neuropathies may be acute or chronic, and may be also categorized as what
Definition
demyelinating, axonal
Term
which neuropathy is more common, demyelinating or axonal
Definition
demyelinating
Term
what is a result of demyelinating neuropathies
Definition
conduction velocities are slowed in axons that have lost myelin
Term
skeletal muscle diseases are conveniently divided into what
Definition
inherited, appear to be acquired
Term
what are the two types of muscular dystrophies characterized by weakness alone
Definition
duchenee, facioscapulohumeral dystrophies
Term
dystrophy that starts in the legs, affects males only, progresses relatively rapidly so that the patient is in wheelchairs by age 12
Definition
duchenne's muscular dystrophy
Term
muscular dystrophy that affects both sexes equally, starts usually in adolescence, affects the shoulder girdle and face early
Definition
facioscapulohumeral muscular dystrophy
Term
what is the 3rd type of inherited muscular dystrophy
Definition
myotonic muscular dystrophy
Term
myotonic muscular dystrophy is characterized by what
Definition
weakness, myotonia
Term
delayed relaxation of muscle after vigorous voluntary contraction, percussion, or electrical stimulation
Definition
myotonia
Term
what is the delayed relaxtion from myotonia caused by
Definition
repetive firing of muscle aciton potentials and is independent of nerve supply because it persists after nerve block
Term
myotonic muscular dystrophy also involves what muscles
Definition
cranial muscles
Term
myotonic muscular dystrophy has limb weakness primarily where
Definition
distal
Term
what is the 4th type of muscular distrophy
Definition
limb-girdle muscular dystrophy
Term
polymyositis is manifest primarily by what
Definition
proximal limb weakness
Supporting users have an ad free experience!