Muscle and Movement Flashcards
(19 cards)
Structure of skeletal muscles
- fascicles = muscle fibres = myofibrils = myofilaments
what do myofibrils contain
myofilaments actin and myosin that interact to cause contractions
sliding filament theory 1
I band = action only
A band = width of myosin
H zone = myosin only
sliding filament theory 2
myosin heads binds to actin forming cross bridges and pull actin towards the M line
- this requires ATP
what does tropomyosin prevent in the sliding filament theory 2
prevents myosin and actin from interacting
by covering myosin biding site until Ca2+ ions bind to it
what is cross bridge cycling
repetitive process of binding, applying force and unbinding of actin and myosin filaments in muscle
what generates the pulling forces in cross bridge cycling
hydrolysis of ATP
is actin also known as the thin filament
True
what is a bundle of muscle fibres called
fascicle
what is a bundle of myofibrillar be called
muscle fibre
what happens when the myosin head binds to an ATP molecule
the cross bridge detaches
where are myosin filaments connected too
The M line
what is the functional unit of a muscle called
Sacromere
what is the sacrolemma
cell membrane of muscle fibre
muscle fibre structure
sarcolemma
sarcoplasm
sarcoplasmic reticulum
myofibrils
transerve tubules (t-tubules)
what are the major steps leading up to skeletal muscle contraction
- events at neuromuscular junction
- excitation - contraction (E-C) coupling
- contraction relaxation cycle
motor unit
motor neuron and all fibres it innervates
neuromuscular junction
are where neuron synapses onto the muscle fibre, initiating contraction
