L1 Flashcards
thick filament of muscle
myosin
thin filament of muscle
actin
M band
thin middle band of myosin
H zone
middle of myosin
A band
myosin that overlaps actin
I band
actin only
characteristics of muscle
irritability - response to stim.
contractility - shorten
extensibility - lengthen
elasticity - return to original length
physiological steps of muscle contraction in sliding filament theory
Action potential
Cross bridge formation
Power stroke
Recovery stroke
types of muscle contraction
isometric
eccentric
concentric
isometric contraction
when a muscle generates force and attempts to shorten, but does not overcome the external resistance
static , no external work but considerable force
concentric contraction
when the muscle shortens and joint movement occurs as tension develops
eccentric contraction
when the external resistance exceeds muscle force and the muscle lengthens while developing tension
muscle types of gross muscle structure
Circular convergent parallel Unipennate Bipennate multipennate
roles of muscles
agonist
synergist
antagonist
fixator
agonist
generates most of the force to make movement
synergist
assists generating the force for the agonist
antagonist
opposes movement of agonist
fixator
stabilises the origin of the agonist muscle
sliding filament theory
- myosin contains ADP and P while actin contains tropomyosin and troponin
- Ca2+ released from sarcoplasm reticulum bind to troponin
- Causes tropomyosin molecules to move and reveal myosin attachment sites on actin
- Phosphate from myosin is released
- Head of myosin attaches to actin - cross bridge
- ADP is used myosin pulls actin inwards = power stroke
- ATP replaces ADP lost in myosin heads - triggers release of myosin heads from actin
- ATP breaks down to ADP + P and returns original position = recovery stroke.
