Exam one Flashcards
how is long bone formed?
endochondral ossification
how does long bone mature
it matures by creating bone (going from osteoblasts to osteocytes
what three factors affect its growth through infancy to old age
mechanical stress (Wolf’s Law), hormones (estrogen/testosterone), and nutrition/calcium
what is 6 degrees of freedom of synovial joint motion
3 degrees translation (bones sliding, caused by individual components of resultant vector) and 3 degrees rotation (degree, torque causes) that occurs at the same time
define qualitative and quantitative analyses with regard to biomechanics
qualitative is what the coach says/what you observe (feedback) and quantitative takes that and assigns numbers
describe how a muscle contraction occurs
voluntarily efferent somatic neuron brings impulse to neuromuscular junction where the nerve (axon terminal) attaches to the fascicle where it is then transferred to the muscle by acetylcholine which opens up sodium channels. Sodium runs along the sarcolemma and then down to the t-tubules. Sodium makes the calcium come out of the terminal cisternae into the SR and down into the muscle chamber where the actin and myosin is. The calcium makes troponin remove tropomyosin from the actin binding site and then the myosin heads attach to the actin, making crossbridges.
describe the power stroke
attachment, pulling, then releasing using ATP, then attaching again. Will continue as long as there is ATP and calcium.
define concentric, isometric, eccentric muscular contractions
concentric: shortening of a muscle to produce force
eccentric: lengthening of a muscle to produce force
isometric: sarcomeres not lengthening while producing force
why does the weight of a dumbbell feel heavier at the end of a curl?
physiological reason: sarcomere is too lengthened.
mechanical reason: external: location of mass of weight moves so the moment arm is smaller. Internal: moment arm between bicep and elbow shortens and muscle is weak.
explain physiological cross-sectional area of muscles; what this means for muscle force population, and how pennation angle affects force production
the bigger the number, the more force capability the muscle will have. More cross-sectional area means more cross-bridges. Pennation increases the cross-sectional area of the muscle which in turn increases force production.
explain in physiologic and biomechanical terms the muscle-force velocity curve relationships for the entire musculotendinous unit with regard to concentric, isometric, and eccentric contractions
the more weight i want to lift, the slower im going to go. It takes time to make cross bridges.
define diarthrodial joint stability and explain what 3 factors biomechanically regulate joint stability
Freely movable synovial joints. bone configuration, number and size of ligaments, and muscle
draw, label, and explain the components of the musculotendinous force-length curve; be able to explain the anatomical structures that contribute to the muscle and fascia/tendon forces and how the shape of these curves relate to force changes as the musculotendinous length changes
force=length curve
