Lecture 18: Skeletal Muscle Pathology I Flashcards
Which of the following is heart vs skeletal muscle
Left: heart- single centrally located nucleus
Right: skeletal muscle- multiple nuclei on periphery
identify 1-6
- Mitochondria
- Glycogen
- Z line
- I band
- M line
- A band
what are myofibers
long and multinucleated cells, little to no regenerative capacity
what are satellite cells
run along length of myofibers and have full capacity of division, fusion, and can restore mature myofibers
what are the physiologic and morphological characteristics of type 1 muscle fibers
Phys: slow twitch, oxidative fatigue resistant, “red muscle” aerobic
Morph: high mitochondria and fat, low glycogen
what are the physiologic and morphological characteristics of type 2A muscle fibers
Phys: fast twitch, oxidative and glycolytic fatigue resistant
Morph: intermediate mitochondria, fat and glycogen
what are the physiologic and morphological characteristics of type 2B muscle fibers
fast twitch, fatigue sensitive, glycolytic “white muscle” anaerobic
Morph: low mitochondria and fat, high glycogen
which muscle fibers are used for long distance
type 1
which muscle fibers are used for short distance, high intensity
2B
how does the percentage of type 1 and type 2 muscle fibers differ in the fore and hindlimbs
more type 1 muscle fibers (postural) in forelimbs
More type 2 muscle fibers (locomotive) in hind limbs
what are the functions of muscle
- Posture and movement including respiration
- Homeostasis- glucose metabolism and body temp
the function of muscles is intimately related to the function of __
PNS
what is a neuropathic change in myofibers
effect of absence of nerve supply
what is a myopathic change in myofibers
primary changers are within muscle cells/fibers
neuromuscular diseases involve __
lower motor neurons, peripheral nerves, NMJ, and muscle
what is the epimysium
surrounds whole muscle
what is perimysium
surrounds fascicle
what is endomysium
around each muscle fiber
what are some clinpath findings that indicate skeletal muscle injury
- Elevated CK (muscle specific)
- Elevated LDH and AST
- Deficient carbonic anhydrase III
carbonic anhydrase III is critical for ___
acetylcholine receptor homeostasis in NMJ
carbonic anhydrase deficiency induces __ leading to __
accelerated degradation of AChR leading to myasthenia gravis
what is wrong in pallor muscle
necrosis, denervation, anemia, young animals
what is wrong in pale streaking muscle
necrosis and mineralization
what is wrong in dark red mottling muscle
congestion, hemorrhagic necrosis, inflammation, myoglobin staining and hypostatic congestion