Muscular System Flashcards
What are the features and example of skeletal muscle tissue
quadriceps
voluntary control, attached to bones, striated appearance
what are the feature and example of cardiac muscle tissue
wall of the heart
Involuntary control
Striated appearance
what are the feature and example of smooth muscle tissue
organs/ blood vessel
involuntary control, smooth appearance ( no striation )
outline the types of muscle action
Concentric- muscle contracts ( shortens)
Eccentric- muscle elongates
Isometric- muscle contracts but no movement
Isotonic- change in length to produce force
outline the gross structure of the skeletal muscle tissue
Epimysium- connective layer that surrounds the whole muscle, separates from other organs
Perimysium- surrounds bundles of fibres ( fascicles), allows for fascicles to be stimulated
Endomysium- surrounds each individual muscle fibre ( cell)
Define the following
Sarcolemma
Myofibrils
Transverse Tubles
Sarcoplasmic Reticulum
Sarcolemma- cell membrane, lipid bi-layer, conducts AP
Sarcoplasmic Reticulum- network of tubular channels, propagate action potentials
Myofibrils- cylindrical functional units within fibres, run parallel to fibres long axis
Transverse Tubules- tube system between SE, pass through the fibre, propogate AP to deeper interior
Define the folowing: Sarcomere, contractile proteins and Z line
Sarcomere- basic contractile unit of a myofibril, light and dark bands ( filaments) give ‘striated’ appearance
Actin- thin filament
Myosin- thick filament
Z line- separate sarcomeres, attachment site of actin
outline the MAIN steps for the contraction of the sacromere
Cross bridge formation
Power Stroke
Detachment of myosin
Resetting of myosin head
explain the cross bridge formation
Calcium binds to troponin
Myosin heads attach to actin binding sites
Myosin head is bound to ADP and Pi
Considered ‘energised’ and yields energy
Explain the power stroke step
Myosin head releases ADP & Pi
Myosin head used energy to pull actin filament
Actin & Z discs move towards centre of sacromere
Explain the steps of the detachment of myosin and resetting of myosin head
ATP is required to remove myosin, enables myosin to reset
ATP is hydrolysed into ADP + Pi
Energy released ‘energises’ the myosin head
Outline the process of excitation- contraction coupling
Excitation- Motor neuron delivers action potential to muscle fibres
Chemical synapse at neuro muscular junction ( Acetycholine), triggers AP in the sarcolemma of muscle fibre
Action potential travels along sarcolemma & down T-tubules
Contraction- AP causes SR to release calcium, calcium binds to troponin
what are the 3 main muscle fibre categories
Slow Oxidative ( Type I)
Fast oxidative- glycolytic ( Type IIa)
Fast glycolytic ( Type IIx)
Outline the size principle
Motor Units recruited from smallest -> largest
force generating capacity are affected by…
Motor unit recruitment ( magnitude & order); muscle temperature; stimulation frequency; resting length of fibres/ sacromere