Muscle Physiology Flashcards

1
Q

Bicarbonate buffer system equation

A

H+ + HCO3- <-> H2CO3 <-> CO2+H2O

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2
Q

4 tissue types in the body

A

muscle, connective, epithelial, nervous

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3
Q

What is histology

A

the study of tissues

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4
Q

What is the largest tissue by mass in the body

A

muscle tissue

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5
Q

What tissue do we really have the most of though, not by mass

A

connective tissue

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6
Q

What are the 3 types of muscle tissues

A

Sleletal: Voluntary control
Cardiac: Involuntary control
Smooth: Involuntary control

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7
Q

What is a fasicle synonymous with

A

muscle cell

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8
Q

What does the epimysium cover

A

the muscle itself

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8
Q

What does the perimysium cover

A

individual fasicles

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9
Q

What does endomysium cover

A

Individual muscle fiber, covers SR and nerve

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10
Q

Thick filament vs thin filament

A

Thick: Myosin
Thin: F-actin (tropomyosin and troponin on them)

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11
Q

Function of myosin2

A

has heads, ATP ase creates power stroke

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12
Q

Function of actin

A

Myosin binding site, actually what does the sliding

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13
Q

Tropomyosin function

A

Blocks myosin binding site with troponin I

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14
Q

Troponin I Function

A

blocks myosin binding site

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15
Q

Troponin T Function

A

Connect troponin to tropomyosin

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16
Q

Troponin C Function

A

Calcium binding site

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17
Q

Actinin function

A

binds actin to Z-lines

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18
Q

Titin function

A

Connects z lines to M lines

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19
Q

Desmin function

A

Binds Z lines to plasma membrane

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20
Q

Dystrophin function

A

Binds actin to dystroglycan complex

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21
Q

What is the largest protein in the body

A

titin

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22
Q

What is duchenne muscular dystrophy

A

Dystrophin protein is absent (anchors sarcomere to plasma membrane)
(tear cell membrane when muscles contract)
Death before age 30 usually

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23
Q

Becker muscular dystrophy

A

Dystrophin is malformed. Sarcomere not anchored well to plasma membrane
(tear cell membrane when muscles contract)

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24
Q

Describe the activation at the NMJ

A
  1. Motor neuron sends an action potential to soma
  2. causes snare proteins to release Ca, which causes acetylcholene release into the synaptic cleft. AcH binds to muscle cell receptors causing Na and K release.
  3. Na enters the muscle plasma membrane, depolarizing cell and creating graded potentials.
  4. Muscle cell reaches threshold, action potential travels to T-tubules and activates sarcoplasmic reticulum which is the release of Ca into sarcomeres
  5. Ca binds to troponin C, changing shape of complex
  6. Moves tropomyosin, exposing myosin binding sites on actin
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25
Q

Cross bridge cycling steps

A
  1. When energized, a Myosin head attaches to actin, forming a crossbridge.
  2. ADP and Pi are released and the myosin head pivots and bends, pulling actin towards M line
  3. After ATP attaches to myosin, myosin head detatches
  4. ATP is hydrolyzed to ADP and Pi, and myosin head is in pre-stroke position
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26
Q

What breaksdown extra AcH

A

Acetylcholine esterase

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27
Q

Mechanism of botulinum toxin

A

blocks AcH release from neuron

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28
Q

Mechanism of myasthenia gravis

A

autoimmune disorder destroys AcH receptors

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29
Q

How many actin per myosin

A

6

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30
Q

What causes power stroke

A

dephosphorylation- phospate comes off

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31
Q

What type of protein is responsible for re-uptake of calcium

A

SERCA

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32
Q

What type of transport is SERCA transport

A

primary active

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33
Q

When is the muscle the strongest

A

When there is myosin atin connection, mid range, where there is optimal overlap to shorten the muscle but not too much that the muscle can’t shorten more.

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34
Q

Concentric, eccentric, and isometric contraction

A
  1. Concentric: Shortening the muscle
  2. Isometric: No movement of muscles
  3. Eccentric: Lengthening muscles
    - Eccentric fully stretches and uses the least electrical activation
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35
Q

Which muscle contraction is strongest

A

eccentric

36
Q

What are the naming of muscle fibers based on

A
  • Myosin, ATP ase, Slow acting or fast acting (how fast they work)
  • Dominant energy system used (oxidative or glycolytic)
37
Q

What are type 1 muscle fibers used for

A

Endurance
slow-twitch, oxidative

38
Q

What are type 2 muscle fibers used for

A

2a: fast twitch, oxidative, glycolitic (2-4 minutes of activity)
2b: Fast twitch, glycolytic (sprinting 30 seconds or less)

39
Q

What is a motor unit

A

one motor neuron and all the fibers it innervates

40
Q

All or nothing princapal of muscle contraction

A

Once an AP reaches a muscle, all the motor units will contract when the siganl reaches (not just some of the parts in the unit)

41
Q

What is the size princapal of muscle contraction

A

small units are recruited before the large units are in muscles

42
Q

What are the characteristics of cardiac muscle

A

branched, gap junction, intercalated disks connecting cells with the gap junctions
Lots of mitochondria (more than skeletal muscle)
Only 1 nucleus per cell (skeletal have many)
All cells in chamber contract at same time

43
Q

Describe calcium-induced calcium release

A

Ca enters cardiomyocyte through L-type Ca channel
Ca activates ryanodine receptors to open SR
Triggers Ca release from SR to increase availability in the cell
SERCA pump returns to normal limits

44
Q

What does cardiac muscle rely on extracellularly

A

Calcium extracellularly to induce SR Ca release

45
Q

Are cardiac muscles anaerobic or aerobic

A

aerobic 100%

46
Q

What does cardiac muscle primarily metabolize

A

lipids (60%)
Carbs (35%)

47
Q

Cardiac muscle resting AP

A

-90

48
Q

What is stretch dependent on in the heart

A

diastolic filling
- When we stretch out the heart, it has a large elastic bouncing back

49
Q

What is sympathetc activation of the heart dependent on and what is the MOA

A

Beta 2 adrenergic increases contractility via:
- Cyclic AMP and protein Kinase A opens CA2 and activates Ca 2 pumping back into SR via SERCA pump

50
Q

What is diastolic heart failure

A

can’t relax heart muscle

51
Q

What does sympathatic activation of the heart lead to

A
  • Increase contractile force in the heart and the releaxation speed (caffine does this too)
52
Q

What are neuroeffector junctions/nerve endings in smooth, cardiac, and skeletal muscle

A
  • skeletal muscle has endplate
  • Smooth muscle: Noradrenergic neurons have varicosities that contain synaptic vesicles.
  • In cardiac muscle, SNS and PNS neurons innervate SA node, AV node, Bundle of HIS
53
Q

Smooth muscle features

A
  • Gap junction between cells, very very few mitochondria
  • multiunit (iris, not connected to other cells ) or unitary(uterus, gi tract, interconnected in large sheets).
54
Q

What type of muscles are blood vessils

A

smooth muscles

55
Q

Does smooth muscle have actin and myosin

A

yes

56
Q

Smooth muscle contraction steps

A
  1. AP leads to Ca influx
  2. Calcium binds to calmodulin protein
  3. Calmoduline activates myosin light chain kinase enzymes
  4. Phyosphorylates myosin, mypsin forms cross bridges with actin and contracts muscles
    Relaxation occurs via MLCP(myosin light chain phosphetase) dephosphorylating myosin
57
Q

What neurotransmitter/ion activates MLCP

A

NO

58
Q

What causes tone in smooth muscles

A

–Latch bridge mechanism leads to extra force of contraction after myosin head already exerts force.
–Continuous electrical activity, keeps blood vessil functioning.

59
Q

What primarily consumes ATP in skeletal muscle?

A

Myosin ATPase (70%)
25% used by CA pumps

60
Q

How much ATP is stored in muscles

A

enough to last 5 secodnds of sprinting or 15 secs of aerobic exercise

61
Q

How long is the energy that creatine gives us ? does it need oxygen?

A

10-15 seconds
Does not need oxygen
Good for extra sprints or single powerful exercises (one more rep)

62
Q

What does exercise lasting more than 1 second produce

A

lactic acid

63
Q

How long does CP system take to recharge

A

2-3 minutes

64
Q

What stimulates the creatine phosphate system

A

ADP and Pi

65
Q

How much ATP does the CP system provide in 10 seconds

A

3 times the amount of stored ATP

66
Q

Glycolosys takes what and makes what

A

takes 1 glucose and makes 2 pyruvate

67
Q

Glycolytic system

A

Glucose-> 2 pyruvate-> go through LDH and done with 2 pyruvate

68
Q

Oxidative system

A

2 pyruvate–> PDH–> Acetyl COA (2)–> krebs cycle, ETC and ATP

69
Q

Glycolytic system ATP increase

A

4 produced
2 or 1 used (2 atp used with glucose, 1 atp used with glycogen)
Net gain of 2 or 3

70
Q

What enzyme breaks down glycogen and kickstarts glycolytic system?

A

Glycogen phosphorylase (PHOS)

71
Q

What does PHOS do

A

Break down glycogen and kickstart system

72
Q

What does PFK do

A

Rate limiting enzyme in glycolytic system, make ATP to ADP

73
Q

What does LDH do

A

turn pyruvic acid to lactic acid

74
Q

What do PDH do

A

Turn pyruvic acid to acetyl coa to start krebs cycle

75
Q

In the glycolytic system:
1. An increase in what leads to an increased concentration of what (that activates glycolytic system)
2. Causes an increase in
3. Which stimulates which enzyme?

A
  1. Increased ATP or AMP activates PHOS
  2. Glucose 6 phosphate
  3. PFK(rate limiting step)
76
Q

What are the most important products of krebs cycle

A

ATP, NADH, FADH2

77
Q

What is the byproduct of krebs cycle

A

CO2

78
Q

What is the rate limiting enzyme in krebs cycle

A

Isocitrate dehydorgense

79
Q

What is NAD+

A

Niacin, B3, drive energy production

80
Q

What is FADH

A

Riboflavin, B5, energy production

81
Q

What type of transport is the ETC

A

secondary active

82
Q

of ATP made from ETC

A

28

83
Q

important byproducts of ETC

A

Oxygen, H2O

84
Q

What drives atp synthase

A

the chemical/electrical gradient of H+
ADP and Pi conversion Makes rotors on synthase spin, create ATP

85
Q

Which muscles have gap junctions

A

smooth and cardiac

86
Q

Which muscle tissues have 1 cell

A

Cardiac muscle and smooth muscle

87
Q
A