Diseases of the Muscle, NMJ, Myotonia Flashcards
(37 cards)
Mechanoreceptor for sensation of deep pressure-pain
Free nerve endings
Are tension receptors that participate in the maintenance of muscle tone and reflex activity
(2)
Golgi tendon organs
and Muscle Spindles
p. 1406
These are specialized groups of small muscle fibers that regulate muscle contraction and relaxation
Muscle spindles
Sheets of collagen that binds together individual muscle fibers into fascicles
Perimysium
a fully formed myofiber has its nuclei located:
A. Centrally
B. Peripherally
B. peripherally
Counting up to 20 equates with a vital capacity of approximately?
20 liters
page 1413
Defining histopathological feature of Inclusion body myositis
intracytoplasmic, subsarcolemmal vacuoles and eosinophilic inclusions in both the cytoplasm and nuclei of degenerating muscle fibers
The following statements are true of inclusion body myositis, EXCEPT:
a. it is common in patients older than 50 years old
b. common in males more than females
c. presents as painless distal weakness in the arms and both proximal and distal weakness in the legs
d. it is responsive to steroids and other immunosuppressive agents
d.
it is not responsive to corticosteroids and immunosuppressive agents.
no benefit of IVIG
plasma exchange and leukocytapheresis - poor results.
page 1423
Main source of energy during exercise (1) ______
later, with exhaustion of glycogen stores, energy is provided by oxidation of (2) ______
1 Glucose
2 fatty acids
difference of myasthenia gravis and botulism
PUPILS
botulism = pupils are usually large and unreactive
eye signs are followed in rapid succession by involvement of the bulbar, trunk and limb muscles
Cancer most often associated with Lambert-Eaton Myasthenic Syndrome
Small cell lung Ca
Gene mutation associated with Central Core Disease?
a. ACTA1 mutation
b. ryanodine receptor 1 gene (RYR1)
c. MTM1
d. Dynamin (DNM2) gene
b. ryanodine receptor 1 gene (RYR1)
IDENTIFY
Gene mutation associated with Nemaline Myopathy
ACTA1 mutation
Nebulin
2 are most common
Pathological finding in nemaline myopathy
red stained rods in the peripheral clusters on Modified Gomori Trichrome stain
Match the following with the enzyme deficiency
- Pompe
- McArdle
- Tarui
- Cori
- Andersen
a. Debranching enzyme
b. Branching enzyme
c. phosphofructokinase
d. alpha-glucosidase
e. myophosphorylase
- Pompe - D. Alpha-glucosidase
- McArdle - E. Myophosphorylase
- Tarui C. Phosphofructokinase
- Cori - A. Debranching enzyme
- Andersen - B. Branching Enzyme
Gene involved in Duchenne Muscular Dystrophy (1)
Codes for this protein (2)
DMD gene
Dystrophin
Autosomal dominant disease presenting as asymmetric weakness of the facial, shoulder and upper arm muscles with sparing of the deltoids
Fascioscapulohumeral dystrophy
childhood/adolescent with classic triad of
- weakness of biceps, triceps, deltoids and typically distal more than proximal legs
- elbow and or ankle contractures
- cardiac conduction defects
Emery Dreifuss muscular dystrophy
Most common adult muscular dystrophy
Myotonic dystrophy Type 1
Which of the following would be a pathological finding in Myotubular myopathy?
A. peripherally placed masses and circular bundles of myofibrils (ringbiden fibers)
B. centrally located nuclei with perinuclear sarcoplasmic reticulum extending radially in a halo formation
C. rod or thread like eospinophilic structures on Gomori Trichrome stain
D. lucent central cores on NADH stain with variably sized fibers with internalized nuclei
Answer: B.
A. peripherally placed masses and circular bundles of myofibrils (ringbiden fibers) - MYOTONIC DYSTROPHY
B. centrally located nuclei with perinuclear sarcoplasmic reticulum extending radially in a halo formation - MYOTUBULAR DYSTROPHY
C. rod or thread like eospinophilic structures on Gomori Trichrome stain - NEMALINE MYOPATHY
D. lucent central cores on NADH stain with variably sized fibers with internalized nuclei - CENTRAL CORE MYOPATHY
Which of the following is NOT a characteristic of Limb Girdle Muscular Dystrophy?
a. patient will not have hypertrophy of calf muscles
b. cardiac involvement is infrequent
c. may have facial muscle involvement
d. mentation is usually normal
c. may have facial muscle involvement
- facial muscles are spared.
Which of the following is true of Myotonic Dystrophy type 1?
a. it is a milder form of myotonic dystrophy
b. it is inherited as a autosomal recessive form
c. caused by an expanded triplet repeat in CNBP gene on Chromosome 3
d. a critical element in pathogenesis of this disease is intranuclear accumulation of the expanded RNA sequences
D. a critical element in pathogenesis of this disease is intranuclear accumulation of the expanded RNA sequences - SEEN in both TYPE 1 AND 2
A, B and C are characteristics of Myotonic Dystrophy Type 2
Gene mutation associated with Malignant hyperthermia
RYR1 gene
ryanodine receptor 1 gene
Which is NOT TRUE of paramyotonia congenita?
a. it is associated with gene mutationin CACNA1
b. it is inherited as autosomal dominant pattern
c. it is characterized by attacks of periodic paralysis associated with myotonia during exercise and worsening as exercise continues
d. it is induced by cold
a.
gene mutation ; SCN4A
