Muscular system Flashcards
Skeletal muscle
Voluntary
Striated
Attach to bone, skin, deep fascia and other muscles
Smooth muscle
Involuntary
Non striated
Lines walls of blood vessels, hollow organs
Name the functions of muscle
Movement
Aids joint stabilisation
Movement of substance within the body
Produces head
Skeletal muscle- excitability/ irritability
Ability to receive and respond to stimuli. I..e neurotransmitters released by herons or hormones distributed in blood
Muscle recruited quickly with significant control over number of muscle fibres
Skeletal muscle - contractility
Ability of muscle to shorten and lengthen when stimulated
Distance muscle shortens limited by physical properties
Skeletal muscle - extensibility
Ability to lengthen due to action of another muscle of external force
Epimysium
Covers the entire muscle
Perimysium
Surrounds bundles of fibres called fascicles- long, cylindrical and vary in length and width
Endomysium
Surrounds individual fibres called myofibrils
Sarcolema
Neurologic innervation of muscle travels through sarcolemma and reaches each individual contractile unit
Myofibril
Strands that run the length of the fibre
Sarcomere
Contractile unit
A band
Contains thick filament and where thick and thin filaments overlap
H zone
Contains thick filaments only
I band
Contains thin filament only
Z lines
Thin filaments are anchored at each side by Z lines which separate each sarcomere from the next
Fusiform muscles
Parallel fibres that run the length of the muscle
Penniform muscles
Fibres run diagonally with tendon running through the muscle
Difference between fusiform and penniform muscles
Fusiform muscles have few fibres which extend length of muscle - greater rang of motion, less power
Penniform muscles have larger number of fibres distributed over tendons - greater lower, less ROM
Slow twitch fibre types type 1
oxidative
found in postural muscles soles
slow contraction times, suited to prolonged low intensity work
Endurance
Fast twitch type 2 a
oxidative glycolytic
sustain long periods or contract with a burst of force and then fatigue
Name the 3 ways which muscle attached to bone
Directly to bone
Via a tendon
Via an aponeurosis
Concentric contraction
Shortens
Muscle torque>resistance torque
Eccentric contraction
Lengthens
muscle torque < resistance torque
Returning to a natural length (after a concentric contraction) or lengthening beyond its natural length
Static contraction
Tension develops within muscle but no change in muscle length/joint angle
Muscle torque is exactly equal to any resistance torque
Prime mover
Muscle primarily responsible for producing a given movement
Stabiliser (fixator)
Contracts statistically to prevent bone at one end from moving
Synergist (neutraliser)
A muscle will contract to eliminate an undesired joint action of another muscle
Neutralisers prevent unwanted accessory actions