Muscle Physiology (6)

Question 1

Skeletal muscles have ________ fibers

Answer 1

striated

Question 2

smooth muscle is under ________ control

Answer 2

sub-conscious

Question 3

whole muscle composed of many ________

Answer 3

fascicles
(which contain clusters of muscle fibers)

Question 4

Fascia

Answer 4

fibrous tissue enclosing muscle
- organize, protect, insulate

Question 5

3 categories of fascia

Answer 5

• epimysium: whole muscle
• perimysium: fascicle
• endomysium: single fiber

Question 6

myo

Answer 6

muscle

Question 7

myofiber

Answer 7

muscle fiber; long cylindrical cell; contains myofibrils

Question 8

myofibril

Answer 8

bundles of myofilaments
- thick and thin filaments arranged into short units called sarcomeres

Question 9

Muscle fibers are multinucleated

Answer 9

several to 100 nuclei, flattened near edge

Question 10

sarcolemma

Answer 10

plasma membrane

Question 11

sarcoplasm

Answer 11

“cytoplasm”

Question 12

sarco

Answer 12

muscle

Question 13

sarcomeres

Answer 13

functional unit; thick and thin filaments

• Z-disc: barrier between individual sarcomeres, anchor in place
• M line: middle; only thick filament

Question 14

Thick filaments

Answer 14

formed of myosin
- two wrapped chains, heads pivot, hinge at tail, ATP required to move

(like arm and fist)

Question 15

Thin filaments

Answer 15

Actin, tropomyosin, and troponin

Question 16

Actin

Answer 16

many units in helix
bind myosin

Question 17

Tropomyosin

Answer 17

covers myosin binding site
- so myosin head cannot bind and cause an unwanted contraction

Question 18

Troponin

Answer 18

binds calcium
- so can open “door” by pulling tropomyosin out of the way
- contraction can happen

TnT interacts with tropomyosin
TnI inhibitory domain
TnC binds calcium

Question 19

Myosin and actin are _______ proteins

Answer 19

contractible

Question 20

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