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
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
