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Flashcards in Muscle Deck (44)
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1

what are the three types of muscle?

Smooth, Skeletal and Cardiac

2

Give 3 examples of where smooth muscle would be found.

Blood vessels, airways, GI tract, vas deferens, bladder, uterus.

3

Is skeletal muscle multinucleate or mononucleate?

Multinucleate

4

Is smooth muscle multi or mononucleate?

mononucleate

5

what attaches muscles to bone?

Tendons

6

what replaces muscle cells after injury?

satellite cells and hypertrophy of other cells to compensate

7

what do the "thick" and "thin" filaments of muscle fibers correspond to?

thick - myosin filament
thin - actin filament

8

what is a sarcomere?

the basic unit of striated muscle tissue

9

what is a cross bridge?

the part of the myosin filament that binds to actin, it contains both actin and ATP binding sites.

10

describe the cross bridge cycle.

the process by which cross bridges on the myosin filament bind to the actin filaments, which induces contraction. the cycle ends with the cross bridges detaching and the muscle returning to a relaxed state

11

what covers the myosin binding site on the actin filaments?

tropomyosin

12

what causes the myosin binding sites on the actin to be exposed?

binding of calcium to troponin; troponin alters shape and pulls the tropomyosin away, leaving the binding site exposed.

13

what is excitation-contraction coupling?

conversion of an electrical signal to mechanical force in a muscle cell

14

what do transverse tubules do?

responsible for spreading depolarization throughout the entire muscle cell

15

how is calcium released from the sarcoplasmic reticulum?

DHP receptors detect depolarization in the transverse tubule, they then send a message to ryanodine receptors, which causes Calcium channels in the sarcoplasmic reticulum to open and release calcium.

16

what is a motor unit?

motor neurons + muscle fibres

17

what is the name given to the force exerted by muscle?

tension

18

what is the name given to the force being exerted on muscle?

load

19

what is the name given to contraction with constant length

isometric

20

what is the name given to contraction with shortening length?

isotonic

21

what is the name given to contraction with increasing length?

lenghthening

22

in a muscle twitch, what name is given to the time between an AP being generated and the muscle displaying a response?

latent period

23

what happens to muscle as load increases?

contraction velocity and distance shortened decreases.

24

what is tetanus?

sustained contraction of muscle fibres with reduced/no relaxation

25

why do muscles fail to contract during tetanus?

calcium levels are never low enough to allow tropomyosin to reblock binding sites on actin

26

what are the antagonistic pairs of muscle arranged around a limb referred to as?

flexors and extensors

27

what causes myosin heads to detach from actin filaments?

binding of ATP to myosin

28

how does calcium transfer back into the sarcoplasmic reticulum?

via calcium ATPase (which is powered by ATP). this ends contraction

29

what is the purpose of fatigue?

to prevent muscles using up vast amounts of ATP which would cause rigor.

30

when does fatigue occur?

after repeated muscle stimulation.