skeletal muscle Flashcards
function of skeletal muscle
movement
posture
heat production
different types of muscle shape
parallel
circular
convergent
pennate (uni pennate, bi pennate, multi pennate)
parallel muscle
good for movement but weak contraction (found in neck)
circular muscle
e.g. sphincter muscles
allows things to shut
convergent muscle
fibres meet at single point
pennate
feather like
muscle fibres insert at an angle into tendon
e.g. muscles of thumb
uni pennate muscle
shorter contraction and shorter range of movement
bi pennate
very strong contraction but short range of movement
multi pennate
strongest contraction but shortest range of movement
general muscle structure
muscle belly with tendon at each end
digastric
2 muscle bellies connected by a tendon
origin of muscle
stationary end
insertion of muscle
more moveable end
1st class lever system
resistance at one end
axis in the middle
force at the other end
2nd class lever system
resistance in the middle
axis at one end
force at the other end
3rd class lever system
resistance at one end
axis at the other end
force in the middle
components of muscle
contractile cells = fleshly muscle belly
connective tissue (fibrous connective)
-surrounds bundles of contractile cells
-at one or both ends of fibrous is tends, connect to bone
skeletal muscle cells
contractile cells and connective tissue
multinucleate cells = muscle fibre
myofibrils = actin and myosin filaments
hierarchical arrangement of fibres surrounded by collagen = allows gliding between bundles of fibres
function of tendons
transfer force to muscle to bone to cause joint movement
myotendinous junction
tendon attachment to musculoskeletal system
junction between muscle and tendon
osteotendinous junction/enthesis
tendon attachment to musculoskeletal system
junction between bone and tendon
biarticular muscles
muscles that cross more than one joint = contraction effects 2 joints (multi articular)
e.g. hamstrings
