BME 2800 Midterm 2 Test With Complete Solution

BME 2800 Midterm 2 Test With
Complete Solution

Skeletal muscle - ANSWER striated and voluntary, well organized

Cardiac muscle - ANSWER Involuntary heart muscle, bifurcated organization

smooth muscle - ANSWER no striations, involuntary

Skeletal muscle functions - ANSWER produce movement, maintain posture,
stabilize joints, generate heat

fascicle - ANSWER bundle of muscle fibers

muscle fiber - ANSWER elongated multinucleate cell

unit cell of a muscle

myofibril - ANSWER tightly packed filament bundles that occupy most of the
cell volume

sarcomere - ANSWER segment of myofibril, contracts muscle

myofillament - ANSWER type 1: Thick, bundled myosin molecules

type 2: thin, actin molecules

M line band - ANSWER the center of the A band, at midline of sarcomere

A-band - ANSWER dark area; extends length of the thick filaments(myosin)

I-band - ANSWER thin filaments only(actin and titin)

Z-line - ANSWER actin filaments are attached in a striated muscle fiber

,marks the boundaries between adjacent sarcomeres.

role of tropomyosin on thin-actin filaments - ANSWER block myosin head
interaction with the actin binding sites thus inhibiting contraction

how do muscle cells contract - ANSWER Calcium binds to troponin

cross bridge cycle - ANSWER repeated sequential interactions between
myosin and actin filaments at cross-bridges that cause a muscle fiber to
contract

Cross bridge cycle steps - ANSWER 1. Binding of myosin to actin

ATP attached to myosin head(at rest)

2. Power Stroke: due ATP hydrolysis myosin head pivots forward, P is then
released, leaving ADP

3. returns to rigor(low energy)

due to ADP leaving

tendon origin - ANSWER type 1 collagen

usually proximal(doesn't move)

tendon insertion - ANSWER tendons are attached to bone, usually distal,
moves, usually a single tendon

slow oxidative(slow twitch) - ANSWER slow ATPase and myosin cycling

highly vascularized=red=ATP abundant and made quickly

good for endurance

fast glycolic - ANSWER fast ATPase and myosin cycling

, few vessels=white=ATP is inefficiently made

good for explosive movements

isotonic contraction - ANSWER constant tensional force

lengthening/shortening




isometric contraction - ANSWER constant tensional force

muscle stays the same length




concentric contraction - ANSWER shortening of muscle




Eccentric - ANSWER lengthening




harder, causes micro trauma(like walking downhill)




Convergent arrangement of fascicles - ANSWER fascicles converge toward a
single tendon

Ex. Pectoralis major




Circular arrangement of fascicles - ANSWER fascicles arranged in concentric
rings