phys unit 3 Flashcards
skeletal muscle
voluntary
cardiac muscle
found only in heart
involuntary
non-striated
smooth muscle
found in hollow organs and tubes
non-striated
involuntary
how is muscle connected to bone
tendons
muscle fiber/muscle cell
one single cell of a whole muscle
muscle is surrounded by…
fascia
sarcolemma
cell membrane surrounding a skeletal muscle fibre
sarcoplasm
cytoplasm of muscle cells
myofibrils
bundles of thick & thin myofilaments filaments
thick filaments
myosin (protein)
thin filaments
actin (protein)
sacromere
functional unit of contraction
motor unit
(somatic) single motor neuron and all the muscle fibers in innervates; stimulates many fibers
motor end plate
area of the muscle fiber sarcolemma where a motor neuron stimulates skeletal muscle; ligand gated receptors
neurotransmitter: ACh
actin binding site
where myson binds to actin
atpase
breaks down atp
actin
contractile protein
tropomyosin
resting, covers myosin binding sites blocking interaction
troponin
shifts it shape
made of 3 units:
binds to tropomyosin
binds to actin
binds with Ca2+
sliding filament mechanism
contraction is accomplished by thin filaments from opposite sides of each sarcomere sliding closer together between thick filaments
- sarcomere brings together = shorter
steps of sliding filament mechanism
- attachment of a myosin cross bridge to a thin filament
- swiveling of myosin head=powerstroke
- detachment of the cross bridge from the thin filament (adp released)
- reattach to a new actin binding site
- repeat cycle
at rest myosin and actin do not interact
true
what allows interaction
troponin tells tropomyosin to move and tropomyosin blocks actin binding sites
