Ch 10 Muscles Flashcards

1
Q

fascicles

A

bundle of muscle fibers or axons

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2
Q

muscle fibers

A

muscle cells

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3
Q

tendon

A

cord of dense regular connective tissue that connects muscle to bone

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4
Q

deep fascia

A

dense sheet of dense irregular connective tissue, separates muscles, binds together muscles with similar functions, fills spaces between muscles

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5
Q

epimysium

A

a layer of dense, irregular connective tissue surrounding a skeletal muscle

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6
Q

perimysium

A

fibrous sheath enveloping each of the fascicles of skeletal muscle fibers

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7
Q

endomysium

A

areolar connective tissue layer surrounding a muscle cell or fiber

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8
Q
A

a. Z disc
b. M line
c. I band
d. A band
e. myosin (thick filament
f. actin (thin filament)

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9
Q
A

a. tropomyosin
b. myosin binding site
c. troponin
d. Ca binding site

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10
Q

explain a twitch

A

electrical impulse travels from brain down axons to neuromuscular junction to activate muscle. changes to a chemical impulse at the synaptic knob in form of acetylcholene. ACh binds to receptors on sarcolemma, which triggers electrical pulse. this travels down the T-tubes and opens Ca gated voltage channels bringing Ca into cell

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11
Q

explain crossbridge cycling

A
  • Ca bind to troponin on thin filament, causing tropomyosin to move and change and expose myosin binding cites on actin
  • myosin heads in cocked position bind to exposed myosin binding site on actin, forming a crossbridge between myosin and actin
  • myosin head swivels toward center of sarcomere, pulling attached thin filament, called power stroke. ADP is released
  • ATP binds to ATP binding site on myosin head, which causes release of myosin head from the binding site on actin
  • ATP is turned to ADP by myosin and provides energy to reset myosin head
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12
Q

sarcoplasmic reticulum

A

stores calcium, wraps around myofibrils (made of myofilaments) and contains Ca pumps to pump Ca into muscle

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13
Q

two ways muscles use ATP

A

crossbridge cycling and Ca pump

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14
Q

three ways to generate ATP in skeletal muscle

A

immediate phosphate transfer, short term supply via glycolysis, long term supply via aerobic cellular respiration

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15
Q

lactic acid

A

made from pyruvic acid when O2 not available
regenerates NAD+ to feed back through glycolysis (forming NADH)

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16
Q

aerobic excercise

A

cycling, walking, jogging, swimming
increase in number of mitochondria, surrounding capillaries, myoglobin synthesis (stores little bit of O2)
no noticeable muscle hypertrophy

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17
Q

resistance exercises

A

weightlifting, isometric exercise
increase in muscle fiber size, number of mitochondria, myofilaments, and myofibrils
store more glycogen
hypertrophy

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18
Q

oxidative fibers

A

fatigue resistant
high endurance due to aerobic respiration
contractions slower, more powerful
extensive capillaries, many mitochondria
large supply of myoglobin (red fibers)

19
Q

glycolytic fibers

A

fatigue-able
ATP is primarily anaerobic
contractions are brief
fewer capillaries, fewer mitochondria
large glycogen reserves
smaller supply of myoglobin (white fibers)

20
Q

fatigue

A

inability to maintain desired power output of muscles
sometimes neurologic
low ATP (low O2, run out of energy reserves)

21
Q

muscle twitch

A

the response of a motor unit to a single action potential

22
Q

latent period

A

time betweeen neural stimulation and muscle contraction

23
Q

contraction

A

active bridging of actin and myosin

24
Q

relaxation

A

cross bridging stops, returning muscle to resting state

25
Q

tetany

A

prolonged contraction caused by many impulses in quick succession

26
Q

motor unit

A

a motor neuron and all the muscle fibers attached to it
neurons can be attached to multiple fibers, fibers attached to only one neuron

27
Q

isotonic contraction

A

muscle length changes

28
Q

concentric isotonic

A

muscle gets shorter as it contracts (picking up baby)
force > resistance

29
Q

eccentric isotonic

A

muscle gets longer as it contracts (putting baby down)
force < resistance

30
Q

isometric contraction

A

muscle length does not change (holding baby)

31
Q

DOMS

A

delayed onset muscle shortage (being sore a day or two later)

32
Q

agonist

A

muscle that provides major force of movement

33
Q

antagonist

A

muscles that reverse a specific movement

34
Q

synergist

A

work w agonist to better produced desired movement
adds more force
stabilizing joints

35
Q

preloading muscle

A

using passive tension (in titan) to help generate force
(stretching the muscle, actin and myosin stretched apart)

36
Q

muscle tone

A

skeletal muscle almost always slightly contracted
keeps muscles healthy, ready to respond, stabilizes joints, maintains posture

37
Q

myasthenia gravis

A

drooping eyelids and muscle weakness
not enough ACh receptors (autoimmune disease where they are destroyed)

38
Q

muscular dystrophy

A

destroys muscle (problems in regulating Ca entry)
appears during childhood

39
Q

cardiac muscle cells

A

short, branching, striated fibers
one or two nuclei, many mitochondria (aerobic respiration)
intercalated discs join ends of neighboring fibers (desmosomes and gap junctions)
contractions started by heart’s autorhythmic pacemaker cells (influenced by ANS)

40
Q

where is smooth muscle found

A

blood vessels, bronchioles, intestines, ureters, uterus

41
Q

smooth muscle

A

fusiform shaped cells, smaller than skeletal fibers
sarcolemma has varied Ca tubes and sarcoplasmic reticulum sparse
fatigue resistant (can maintain contraction without ATP through latenbridge mechanism)

42
Q

frequency

A

repeated firing of a single motor unit until fused tetanus is reached

43
Q

recruitment

A

activating additional motor units to increase force