Structure and function of muscles Flashcards
function of muscles
produce movement
maintain posture and positions
protection
heat generation
drive circulatory system (vascular pump)
types of muscles
smooth
cardiac
skeletal
muscle fasicle
bundle of muscle fibres
tens-osseous junction
where tendon attaches to bone
musculo-tendinuous junction
where tendon attaches to muscle
aponeurosis
thin sheet of tendon where muscle fibres meet
parallel muscle
where muscle fibres are parallel to each other e.g. biceps brachii
pennate muscles
where muscle fibres are packed at an angle to one another (fibres not aligned to muscle axis)
which is stronger: parallel or pennate muscles?
pennate as more fibres are packed into the same spaces and they have a higher physiological cross-sectional area
which is faster: parallel or pennate muscles?
parallel as fibres shorten over a smaller distance
isometric contraction
external force is equal to muscle force so length remains the same
concentric contraction
when external force is less than muscle force so muscle shortens
eccentric contraction
external force is greater than muscle force so muscle lengthens
structure of muscle fibres
muscle fibres and myofibrils are striated
muscle fibres are bundles of myofibrils
a sacromere is the most functional unit of muscle fibre
sarcomere consists of actin and myosin filaments
actin and myosin filaments slide towards each other
how do muscles produce movement?
actin and myosin filaments slide towards each other
source of sliding forces come from interactions between myosin heads and actin binding sites
