Skeletal Muscle Flashcards Preview

Fundies First Module--First Exam > Skeletal Muscle > Flashcards

Flashcards in Skeletal Muscle Deck (47):
1

How to differentiate muscle

1. structure (skeletal, cardiac, visceral)
2. Histological (striated, smooth)
3. control mode (voluntary, involuntary)

2

only skeletal muscle not attached to bone

tongue

3

more nuclei

skeletal

4

sphincters formed by

smooth muscle

5

surrounding muscle fibers

fascicle

6

muscle fiber=

muscle cell (multineucleated--extend length of muscle)

7

slow fibers

slow cross-bridging/ linking --much myoglobin

8

More mitochondria

slow fibers

9

slow fibers for

postural muscles, endurance, less fatigue (Type I myosin)

10

sarcoplasmic reticulum for

communication throughout muscle--store Ca--> release when activated

11

myofibril

hundreds make up one muscle fiber/ cell--made of stacked sarcomeres

12

A band is

NOT actin--myosin (thick) -- (has heads)

13

I band is

ACTIN (thin)

14

where filaments meet

M band (middle of sarcomere) (myosin)

15

Z line -- Z line

sarcomere (functional unit of muscle--contraction)

16

myosin protein attaches to the actin at

the heads

17

Ca binds to

G actin binding site

18

I band

thin actin filaments--narrows upon contraction

19

H bands disappears

at full contraction

20

membrane surrounding muscle cells

sarcolemma

21

holding cistern of Ca

terminal cisternae

22

Ca binds to

troponin complex --> tropomyosin changes conformation --> allows myosin heads to attach to actin binding sites

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mitochondria in

sarcoplasm

24

axon + muscles it innervates

motor unit

25

period when muscle cannot be activated

absolute refractory period

26

when ATP attaches to recently power stroked myosin head

myosin head releases from actin --> ATP is broken down into P and ADP--releasing energy into myosin head --> ready for next power stroke

27

parts of sarcoplasmic reticulum

terminal cisternae at ends of T tubules -- hold Ca for release

28

destroy presynaptic motor neuron

flaccid paralysis-- polio-->muscle weakness

29

block release of ACh at neuromuscular junction

botulinum toxin--botox

30

Destroy post-synaptic receptors

myasthenia gravis

31

muscle is prevented from shortening when activated--no physical work done despite force development

isometric contraction--i.e. pushing on brick wall

32

Muscle is allowed to shorten while maintaining constant force

isotonic contraction--preceded and followed by isometric contraction

33

Lifting weight

isometric-isotonic-isometric contractions

34

muscle shortening

concentric contraction

35

muscle elongating--muscle contracts with force less than resistance

eccentric contraction

36

contracting =

concentric

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eccentric =

elongating

38

when not being used Ca goes

back to sarcoplasmic reticulum

39

rigor mortis caused from

no ATP due to dead cells--engaged myosin heads--relaxation from foot upward

40

not enough Ca in blood--less than 50% saturation

no conformational change of tropomyosin--tetany
overactivation of motor nerves--> spasms (tetany)

41

coke/tea urine

rhabdomyolysis--myoglobin in blood--break-down products can damage kidneys

42

increase in muscle cell size--can't add muscle cells

hypertrophy--myonuclear addition

43

Skeletal muscle tests

1. serum creatine kinase--abnormal if leaks into serum
2. myoglobin--released after muscle injuries-urine tested after injury
3. EMG--measures summation of AP in motor unit--milivolts/ms
4. Biopsy
5. strength and ROM

44

defect in X chromosome leading to absence of dystrophin (anchors cytoskeleton)

Duchaen Muscular Dystrophy--tears muscle cells rather than contracting--tight heal cord (toe walking) WEAK Muscles. Weak hip flexor muscles--leading to "cowboy walk"

45

walking up the legs to rise to standing

Gower's sign--indicative of lower body weakness

46

Force / velocity relationship

Lighter the force (less force), the faster it will move

47

Tension (skeletal muscle) becomes _______ in cardiac muscle

Stroke volume