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Details

Normal Muscle
MS Module
47
Medical
Graduate
05/14/2009

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Cards

Term
Which are the thick and thin myofilaments?
Definition

thick= myosin

thin= actin

Term
What is the order from largest unit to smallest unit of muscle? (6)
Definition

muscle

fasicle

fiber

myofibril

myofilaments

sarcomere

Term
WHat connective tissue layer surrounds the muscle itself?
Definition
epimysium
Term
WHat connective tissue surrounds the fasicle?
Definition
perimysium
Term
What connective tissue surrounds each fiber of muscle?
Definition
endomysium
Term
What histological feature of the tendon makes it not a good idea to take a biopsy from the myotendinous junction?
Definition
nuclei that are internal
Term
Where in the muscle do you not want to take a biopsy?
Definition
the myotendinous junction
Term
What is the normal transverse shape of the muscle fiber?
Definition
polygonal
Term
Where are the organelles located within the muscle?
Definition
between the myofibrils
Term
What are the stem cells of the muscle cells called?
Definition
satellite cells
Term
WHere are the satellite cells found within the muscle?
Definition
within the basement membrane of the muscle fiber
Term
What occurs to the satellite cells with increasing age?
Definition
they decrease
Term
What is the difference between the number of nuclei in a muscle cell and a satellite cell?
Definition

muscle cell is multicellular

satellite cell has a single nucleus

Term
WHat is the light band of the muscle fiber in longitudinal section?
Definition
I band
Term
Which band does not get smaller when the muscle contracts?
Definition
A band
Term
What color fiber is type one and why?
Definition
red becuase of increased myoglobin and being more vascular
Term
What type of twitch is type I fiber?
Definition
slow
Term
Which type of fiber has more mitochondria?
Definition
type I
Term
Which fiber is dark on SDH stain?
Definition
type I
Term
What type of fixing must be done to muscle to see enzyme activity?
Definition
frozen
Term
Which type of fiber has increased lipid?
Definition
type I
Term
WHich type of fiber has increased glycogen/phosphatase?
Definition
type II
Term
WHich fiber is darker on ATPase stain?
Definition
type II
Term
Why does muscle stain with ATPase stain?
Definition
artifact
Term
What is the ratio of type 2 to type 1 fibers?
Definition
2:1  there are more fast twitch
Term
Which muscle proximal or distal has larger fiber radius?
Definition
proximal
Term
What is the size of the type 2 vs. type 1 fibers in a male?
Definition
type 2 fibers are larger than type I
Term
Which sex has larger fibers?
Definition
males
Term
What is true of female type one and two fiber size?
Definition
they are the same size
Term
What age is the peak diameter of muscle size?
Definition
21-25
Term
At what age does the muscle strength decrease about 50%?
Definition
75
Term
WHat fiber mostly atrophies as one ages?
Definition
type 2
Term
Why is an electrodiagnosis with nerve conduction or EMG a first line test?
Definition
less invasive then a biopsy
Term
What does latency mean when doing nerve conduction test?
Definition
the time between stimulating the nerve and when the CAMP occurs
Term
WHat is CMAP?
Definition
compound motor action potential
Term
If there is slower conduction what will be true of the latency?
Definition
it will be increased
Term
IF stimulated at the elbow and the wrist, what should be true of the CMAP?
Definition
should be same size
Term
What is the characteristic of the normal action potential of muscle?
Definition
triphasic
Term
WHat occurs when the needle for the nerve conduction test is inserted into the muscle?
Definition
insertational activity
Term
What does it mean if the insertional activity is prolonged with increased amplitude?
Definition
denervation or myotonia (membrane instability)
Term
What does the amplitude mean?
Definition
density
Term
What does the duration of the action potential indicate?
Definition
# of fibers
Term
What occurs to fibers in denervation?
Definition
they get smaller and the density gets larger
Term
When does type grouping occur?
Definition
when reinnervation occurs and one type takes over for the other
Term
After denervated for 10 days what can occur to the muscle?
Definition
fibrillation
Term
What does a bimodel histogram indicate about muscle?
Definition
type grouping
Term
What are four causes for type 2 atrophy?
Definition

aging

myasthemia gravis

steriods

disuse of the muscle

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