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Flashcards in Skeletal Muscles Deck (72):
1

which muscles can regenerate?

smooth (uterus)

2

which muscles cannot regenerate easily?

skeletal
cardiac

3

what do the intercalated discs represent?

where one cardiac cell joins with another

4

which type of muscle is most prominent?

smooth muscle
(skin, uterogenital, etc, etc)

5

endomysium

wrapping that surrounds a single muscle fiber

6

perimysium

wrapping that surrounds a fascicle (bundle of single muscle fibers)

7

epimysium

wrapping that surrounds an entire muscle

8

thick filament

myosin

9

thin filament

actin (globular actin)
tropomyosin
troponin

10

dark band

A- band
(anisotropic)
-thick and thin filament

11

light band

I-band
(isotropic)
-only thin filament

12

which type of fiber moves during muscle contraction?

thin filament

13

why is the z-line so important?

distance between z to z gets shorter when contraction takes place

14

sarcomere

from z-to-z

15

titin

muscle protein that is attached to the thick filament in the sarcomere (helps recoil)

16

what does the H zone contain?

only myosin (no thin filament)

17

which band disappears when muscle contracts

I-band

18

where is Ca stored in the skeletal muscle fiber?

sarcoplasmic reticulum

19

sarcoplasmic reticulum

modified smooth ER inside muscle cells

20

sarcolema

plasma membrane of muscle cell

21

transverse tubules (t-tubules)

go into the muscle cells from outside to in

22

what are the three subunits of troponin?

troponin C (binds to calcium)
troponin T (binds to tropomyosin)
troponin I

23

what kind of tissue is epimysium?

dense irregular CT

24

what kind of tissue is perimysium?

dense irregular CT

25

what kind of tissue is endomysium?

loose areolar

26

fascia

supports and surrounds entire organs and muscles

27

superficial fascia

separates muscle from skin
loose areolar CT

28

deep fascia

holds muscles with similar functions together
dense irregular CT

29

compartment syndrome

muscle swells, but fascia does not give, which occludes blood supply because of pressure on tissues
-treatment is fasciotomy
-swelling peaks 48-72 hours after trauma

30

aponeurosis

broad, sheath-like tendon

31

what does the m-line contain?

thick filament with protein

32

what are the structural proteins in muscle?

actin,
myopsin,
dystrophin, attaches to myofibrils and the other end is attached to plasma membrane (anchors myofibrils)
titin,
myomesin

33

muscular dystrophy

duchennes-x-linked recessive
-genetic defect where dystrophin is abnormal, architecture of the muscle is out of wack and muscle fibers degrade and normal muscles turn into adipose tissue

34

myoglobin

cell that carries oxygen to the muscles (supposed to be inside the cell)

35

who is the primary intracellular cation?

potassium (K+)

36

rabdomyolosis

breakdown of muscle fibers that leads to myoglobin in blood which is toxic to kidneys and can cause kidney damage
-trauma
-overexcersion

37

sudden surge of potassium from muscle cells can cause

stopping of heart
renal failure

38

glycogen

storage form for glucose
-stored in skeletal muscle and liver

39

which type of filament is more prominent in muscle?

thin filament

40

what type of design does thin filament make around thick filament?

hexagonal

41

concentric

contraction with shortening

42

isometric

contraction without shortening

43

eccentric

contraction with lengthening

44

how do the ends of muscles move?

one end stays stationary while the other end shortens

45

what are the two binding sites on myosin?

1. thin filament
2. ATP

46

what happens during the resting state?

concentration of cytoplasmic calcium is low (stored in sarcoplasmic reticulum)
myosin are in an energized state

47

allosteric modification

adjacent binding sites modify the affinity of binding in other sites
(when ATP binds to myosin head, it decreases affinity to bind to tropomyosin site)

48

excitation-contraction coupling

sarcolemma of the muscle fibers leads to cross-bridge formation and contraction

49

what type of leakage channels does sarcolemma have?

Na+ (goes out) and K+(has more of these) (goes in)

50

what established gradient of Na and K

sodium potassium pump

51

what is the resting membrane potential?

-70mV

52

action potential completes before what?

contraction

53

what is the threshold?

-55mV

54

what is the maximum gradient of an AP?

+30mV

55

what is the triad?

t-tubule is connected to sarc. reticulum on either side

56

what is the foot protein involved in calcium release?

ryanodine receptor (forms a calcium channel)

57

what is responsible for returning calcium to the SR?

calcium-ATPases

58

motor end plate

area that is modified in the skeletal muscle that has the receptor for the nerve transmitters
-contains envagination called junction folds

59

motor neuron terminal

contains acetylcoline

60

motor unit

single motor neuron and all the muscle fibers it innervates

61

somatic motor (efferent) neurons

cell bodies in brain and ventral gray matter of spinal cord
largest diameter axons in body
myelinated

62

nicotinic receptors

cholinergic receptors at the motor end plate

63

cholinergic receptors come in two types

nicotinic receptors
muscurinic receptors

64

what ions are allowed to flow when an acetylcholine comes through the motor end plate?

Na and K

65

what clears out acetylcholine?

acetylcholinesterase

66

acetylcholinesterase inhibitors

used for Alzheimers medicines
-may slow illness slightly, but does not do much else

67

IPSP

inhibitory post synaptic potential

68

what types of ion channels are present in sarcolemma and along axons of neurons

individual voltage gated sodium and potassium channels

69

curare

binds to nicotinic receptor but does not open Na channels
-is not degraded
-muscle paralysis including respiratory muscles

70

gallamine

similar to curare
used to induce muscle paralysis during surgery when the airway is controlled

71

organophosphates

insecticides and nerve cases
inhibits acetylcholinesterase
-maintain depolarization
-receptors become insensitive

72

botox

prevents vesicular fusion needed to acetylcholine release from motor neuron synaptic end bulb

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