| A | B |
|---|
| endomysium | loose connective tissue covering each fiber |
| fascicles | bundles fibers are organized into |
| perimysium | cover fascicles |
| epimysium | fascia surrounding whole muscle |
| sacromere | banding patterns of myofibrils along length of muslce |
| two types of fibrous filaments that compose myofibrils | actin-thin filaments and myosin-thick filaments |
| sarcoplasmic reticulum | organized network of sacs. stores calcium |
| transverse tubule system | allows for movement of fluids into and out of muscle cells |
| sliding filament theory muscle contraction | active shortening of the sarcomere results from the relative movement of the actin and myosin filaments past on another (each filament retains its orginal length). the force of contraction is developed by myosin heads (or cross bridges) in the region of overlap (A band). the movement of the cross-bridges in contact with teh actin filaments produces a sliding of the actin towards the center of the sarcomere |
| parallel fiber muscle | fascicles are arranged parallel to the long axis of the muslce. flat fusiform, stra, radiate, convergant shapes |
| fiber force in a parallel muscle fiber arrangement is in...this results in... | the same direction as the musculature, a greater range of shortening and greater movement velocity |
| pennate arrangement | fibers run diagonally with respect to a central tendon running the length of the muscle. force generated by each fiber is in a different direction than the muscle force. fibers shorter and change in individual fiber length is not eqyal to change in muscle length. have large cross sectional area and generate more strength than parallel fiber muscles |
| typeI fiber | slow twitch fibers have slow contraction times for prolonged, low-intensity work |
| type IIA | fast twitch oxidative fibers can sustain activity for long periods or contract with a burst of activity and then fatigue |
| typeIIB | fast twitch glycolytic fibers generate rapid force production and then fatigue quickly |
| motor unit | functional unit of skeletal muscle. includes a single motor neuron and all of the fibers innervated by it. when stimualted all muslce fibers respond as one. fine movements=motor motro units with less fibers per unit. |
| twitch | the mechanical response to a single stimulus of its motor nerve |
| summation | when mechanical response to succesive stimuli are added to an initial response |
| concentric contraction | muscles develop sufficient tension to overcome the resistance (muscle shortens while developing tension) |
| eccentric contraction | muscles cannot develop sufficient tension to overcome the resistance (muscle lengthens while developing tension) |
| isometric contraction | muscles develop sufficient tension to balance the resistance (muscle length stays the same while developing tension) |
| muscle torque | muscle force times moment arm. must overcome external load to move |
| the longer the contraction time...the force developed up to the point of max tension | greater the force developed |
| increasing the temp | increase in conduction velocity across sarcolemma, thus increasing the frequency of stimulation, thus increase the muscle force |
| ability of muscle to contract and relax is dependent on availability of | ATP. frequency must be low enough to allw the muslce to synthesize ATP at a rate sufficient to keep up with the rate of ATP breakdown |
| origin | proximal attachment |
| insertion | distal attachment |
| depending on the angle of...some force is directed to .... | angle of inseriton, stabilizing joint |
| agonsits | muscle creating a specific joint movement |
| antagonists | muscles opposing or producing the opposite moevment to the agonists |
| stabilizer | muscles that act on one segment so that a specific movment in an adjacent joint can occur |
| synergist (neutralizer) | muscles that contract to eliminate an undesired joint action of another muscle |
| rectus femoris | creates hip flextion and knee extension |
| hamstrings | creates hip extension and knee flexion |
| gastrocnemius | creates plantar flexion and knee flexion |
| passive insufficiency | two joint muslce is constrained in elongation |
| active insufficiecy | two joint muscle constrained in contraction |
| strength | max force produced by muscle or muscle group. or mechanically the max isometric torque at a given angle |
| variables affect strength | type of muscle action, speed of movement, length of muscle |
| training for strength involves.. | increasing the cross sectional area of the muclse (tension/unit of PSCA) |
