Muscles Flashcards
Duchenne muscle dystrophy characterization
Some muscle cells die and are replaced by fat cells
-not expected in healthy muscle
excitation of a muscle can come from
nerve
gasses (NO)
horomones
Smooth muscle;
characteristics
what stims contraction
found where
- Non straited, uni nucleated, cigar shape
- Contracts via hormonal or physical stim
- Digestive tracts, respiratory tract, vascular system
Skeletal muscle;
characteristics
- voluntary
- striated
- multinucleate cells
cardiac cells;
characteristics
- involuntary
- striated
- uninucleated
- tick by themselves thru inner clock
- cant stand ox debt
Organization of muscle fibres from small to big
Myofibrils- actin, myosin, titin
Myofibres
Fasicles
Sheeths of muscle coverings from small to big
Endomysium
Perimysium
Epimysium
What is the cause of ducheen muscular dystrophy
Dystrophin gene mutation
- dystrophin usually connects actin to collagen fibres in the envalope
- it is broken in dystrophin muscular dystrophy
what is one sarcomere
-z band to z band
what do the transverse tubules do
- facilitate the conduction of waves of depolarization along the sarcolemma
what stores the intracellular calcium
sarcoplasmic reticulum (forms terminal cisteernae at each ai junction
what is the triade
- made of 2 terminal cisteerne and t tubule
- source of depolarization
how does the muscle contract
- myosin (thick) hook to actin (thin) and move them to the center M line
- z lines come closer together
How does the muscle cell relax
Titan acts like a spring (is from z line to m line)
what happens at the neuromuscular junction
- Nerve impulse travels down
- efflux of calcium
- triggers release of ACh
