Force of contraction Flashcards
(21 cards)
what does graded musclle contracction mean
efers to the ability of muscles to vary the force of their contractions to meet different demands
what are the 2 types of grading
increase in frequency (temporal summation)
increase in strength (recruitement)
what is temporal summation
repeated or rapid stimuli, arriving at a synapse or neuromuscular junction in close succession, lead to cumulative effects
in muscles, it contributes to the increased force and frequency of contractions.
how many phases of temporal summation are there?
4 phaes
what happens in tetanus
repolorisation does not occur
sustained muscle contraction
what happens in unfused (incomplete tenatus)
ca2+ satuation not constant
what happens in fused (complete tetanus )
continual ca2+ saturation
what are some muscle fibre properties
Length at onset of contraction:
Optimum length
Optimal overlap of thick and thin filaments
Greatest force generation
what is the dimater of a muscle fibre
Vary between 10-100 m
what happens when a muscle fatigues?
phsiological inability to contract muscles
complex chemical changes within the muscle
Ionic imbalances
Decreased glycogen
Increased lactic acid
Neuromuscular depletion
what are the 3 levels frequency of muscle fatigue
low
intermidate
high
low muscle fatigue
-little fatigue and constant tension
intermediate muscle fatigue
-eventual fatigue and gradual decline
high muscle fatigue
maximum tetanic tension
rapid fatigue
what are the 2 types skeletal muscle fibre type
fast fibres
slow fibres
what are the slow muscle fibres like>
Half diameter
3x longer to reach peak tension
Extensive capillary network (myoglobin)
what are the fast muscle fibres like?
Rapid contraction speed
High force generation
Fatigue more quickly than slow-twitch fibers
Primarily rely on anaerobic metabolism for energy
what can graded contraction be affected by
Graded contraction can be affected at a muscle fibre level by temporal summation, fibre diameter, muscle fibre length and fatigue.
why do muscles use grade contraction
Muscles used graded contractions to generate smooth movement and control force of movement.
