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Anatomy & Physiology 1 > Muscular System > Flashcards

Muscular System Flashcards

1
Q

what is the sarcolemma?

A

plasma membrane of a muscle cell

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2
Q

what is the sarcoplasm?

A
  1. cytoplasm of a muscle cell

2. contain all the “Normal” organelles of a typical cell

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3
Q

what is a myofiber

A

a muscle cell, has elongated shape

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4
Q

what is the sarcoplasmic reticulum

A

Endoplasmic reticulum of a muscle cell

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5
Q

what are myofilaments

A

Long protein fibers within a muscle cell

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6
Q

what is the organization of skeletal muscle

A
  1. muscle cell is called myofiber
  2. Myofiber contains bundles of Myofibrils
  3. Myofibril contains bundles of Myofilaments
  4. Myofilaments are long proteins, either
    >Myosin (Thick filament)
    >Actin (Thin filament)
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7
Q

what is the basic unit of contraction in a myofiber

A

sarcomere

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8
Q

actin filaments are attached to what protein fiber at each end

A

Z-disc

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9
Q

how do sarcomeres shorten

A

the actin filaments slide over the myosin filaments

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10
Q

what are the two components of sarcomere contraction

A
  1. Mechanical component

2. On/Off Switch component

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11
Q

what is the mechanical component of sarcomere contraction

A
  1. the Sliding Filament Theory- how a sarcomere shortens
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12
Q

what is the action of contraction

A

the sliding/pulling of actin (thin) filaments over myosin (thick) filaments

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13
Q

what are myosin globular heads

A

extensions, located at each end, off the main protein of the myosin filament

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14
Q

what is the function of the myosin globular head

A
  1. form cross-bridges (bonds) to the surrounding actin filaments
  2. used to slide (pull) actin towards center
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15
Q

myosin globular heads are what at the start of a contraction

A

in the “cocked” position ready to fire

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16
Q

what is the power stroke

A

the action of myosin globular heads pulling the actin towards center of sarcomere

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17
Q

what is needed to “cock” the heads of the myosin globular heads

A

ATP

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18
Q

what are the steps of the on/off switch component of contraction

A
  1. signal travels from brain along neurons to muscle
  2. signal reaches muscle at the motor neuron
  3. signal is transmitted across sarcolemma by acetylcholine
  4. acetylcholine cause calcium in sarcoplasmic reticulum to enter sarcoplasm
  5. calcium in sarcoplasm allows cross bridge between actin & myosin globular head
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19
Q

what is the “switch”

A

process of calcium entering sarcoplasm that allows cross bridge between actin & myosin globular head to form

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20
Q

what are the two proteins that function as part of the “switch”

A
  1. troponin

2. tropomyosin

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21
Q

what is function of troponin

A

binds to calcium ions

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22
Q

what is function of tropomyosin

A

covers the cross bridge site on actin

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23
Q

what protein is linked to another protein to form a unit

A

troponin to tropomyosin

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24
Q

what is the function of calcium ions in contraction

A
  1. binds to troponin to cause it’s shape to change
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25
what happens when troponin shape changes
it moves the tropomyosin to expose the cross bridging site on actin so that the myosin globular heads can bind to actin
26
what is the purpose of myosin globular heads to be cocked
1. to be in postion to cross bridge with actin | 2. stores necessary energy needed to slide actin
27
the return of a sarcomere to its original length is called
relaxation
28
what events need to happen for a sarcomere to relax
1. signal from motor neuron must stop 2. acetylcholine must be broken down 3. calcium ions in sarcoplasm must reenter sarcoplasmic reticulum
29
how is acetylcholine broken down
1. enzyme found in sarcolemma called acetylcholinesterase converts acetylcholine into acetyl CoA & choline
30
how are calcium ions moved back in the sarcoplasmic reticulum
enzymes in SR use active transport to transport it from low to high concentration gradient
31
when is ATP needed for muscles to contract
1. to cock myosin globular heads 2. to release myosin globular heads 3. to move calcium ions back into SR 4. to generate signals from motor neurons
32
what allows skeletal muscle to have a constant supply of ATP
1. stores its own glycogen 2. has its own form of hemoglobin called myoglobin 3. has an extensive blood supply
33
what does oxygen debt refer to
the amount of oxygen needed to get rid of the lactic acid build up from anaerobic activity
34
what are the factors that muscle fiber type is based on
1. rate that sarcomere shortens | 2. type of energy pathway used to make ATP
35
what are the two classifications for muscle fibers based on rate of contraction
1. fast twitch | 2. slow twitch
36
what are characteristics of slow twitch
1. conserves ATP | 2. found in muscles needed for endurance
37
what are characteristics of fast twitch
1. uses ATP quickly | 2. found in muscles that provide fast, quick movements
38
what are the classifications used to determine muscle fiber types by energy pathways
1. glycolytic | 2. oxidative
39
how does the oxidative pathway produce ATP
1. has multiple mitochondria 2. is always aerobic 3. uses glycolysis, citric acid, & electron transport to produce 38 ATP per glucose molecule
40
how does the glycolytic pathway produce ATP
1. has fewer mitochondria 2. is always anaerobic 3. uses only glycolysis to produce 2 ATPs & lactic acid per glucose molecule
41
what are the types of muscle fibers & their classification
1. type I (slow-twitch, oxidative) 2. type II (fast-twitch, glycolytic) 3. type II-a (fast-twitch, oxidative)
42
describe type I fibers
1. is slow-twitch & oxidative 2. resistant to fatigue 3. has multiple mitochondria 4. has high level of myoglobin 5. has extensive blood supply 6 . referred to as red fibers
43
describe type II fibers
1. is fast-twitch & glycolytic 2. fatigues easily 3. has fewer mitochondria 4. low level of myoglobin 5. has less blood supply 6. referred to as white fibers
44
describe type IIa fibers
1. is fast-twitch & oxidative 2. intermediate/hybrid type of fibers 3. resists fatigue 4. more mitochondria 5. moderate blood supply 6. intermediate level of myoglobin
45
when does whole muscle contraction occur
1. when there is cross-bridging between actin & myosin | 2. when there is tension/force being generated
46
what are the types of muscle contractions
1. isometric | 2. isotonic
47
what is an isometric contraction
muscles generate a force but sarcomeres don't change length
48
what is an isotonic contraction
muscles generate a force & sarcomeres do change length
49
what are the two types of isotonic contraction & their movement
1. eccentric-sarcomere lengthens | 2. concentric-sarcomere shortens
50
what is an origin
the immovable end of a muscle
51
what is an insertion
the movable end of a muscle
52
what is a prime mover
muscle primarily responsible for movement
53
what is a synergists
muscle that assist the prime mover
54
what is an antagonist
muscle that resists primer mover's action and causes movement in the opposite direction
55
skeletal muscles names are based on what
1. size 2. shape 3. location 4. action 5. # of attachments 6. direction of fibers
56
what is flexion
angle decreases between bones on either side of a joint
57
what is extension
angle increases between bones on either side of a joint
58
what is abduction
moving a part away from midline
59
what is adduction
moving a part towards midline
60
what is rotation
moving a part around a axis
61
what makes the foot a special structure
ankle joint allows movement both anteriorly & posteriorly
62
what is dorsiflexion
movement of the ankle to bring the toes closer to the tibia
63
what is plantar flexion
movement of the ankle to bring heel closer to the tibia

Anatomy & Physiology 1 (12 decks)

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