L10- Mucles Flashcards

1
Q

What are the 3 types of muscle tissue?

A

Skeletal, cardiac and smooth muscle

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2
Q

Skeletal muscle location & function

A

Location = attaches bones across joints

Function = moves joints ➡️moves the body

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3
Q

Smooth muscle function and location

A

Location = around tubes and sacs

Function = open/ close tubes
Regulate diameter of tubes
Propel material through tubes

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4
Q

Cardiac muscle function and location

A

Function: create driving pressure to move blood thoughts vessels

Location= heart

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5
Q

What muscle tissues are striated?

A

Skeletal and cardiac muscle

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6
Q

What muscle types are voluntary and which are involuntary?

A

Skeletal muscle = voluntary

Cardiac and smooth = involuntary

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7
Q

What is the primary function of skeletal muscle?

A

Energy transducer

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8
Q

What happens in a skeletal muscle when it is contracted vs relaxed?

A

Contracted = active
- Motor neuron Ap releases Ach ➡️ binding to Nicotinic receptor ➡️ depolarization = contraction

Relaxation = passive

  • no action potentials to motor neuron
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9
Q

Structural hierarchy of skeletal muscle

A

Muscle ➡️ fascicle ➡️ muscle cell (myofiber) ➡️ myofibril

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10
Q

Fascicle

A

Bundle of muscle cells

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11
Q

Muscle cell (myofiber)

A

Muscle fiber

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12
Q

Myofibril

A

Chain of sarcomeres

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13
Q

What is a sacromere

A

Made up of thick (myosin) and thin (actin) filaments

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14
Q

Sarcoplasm

A

Cytoplasm

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15
Q

Sarcolemma

A

Plasma membrane

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16
Q

Sarcoplasmic reticulum stores

A

Calcium ca+

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17
Q

What conducts Ap to the sacroplasmic reticulum?

A

Transverse (t) tubules

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18
Q

What is the flow of an action potential traveling down sarcolemma

A

Action potential down sarcolemma ➡️ t tubules ➡️ signals saroplasmic reticulum to release ca2+ ➡️ ca2+ bathes myofibers ➡️ initiating contraction

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19
Q

Sarcomere

A

Z disc to z disc

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20
Q

What are thick and thin filaments made out of?

A

Thick = myosin

Thin = actin

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21
Q

H zone

A

Thick filaments only

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22
Q

A band

A

Thick and thin filaments

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23
Q

I band

A

Thin filaments only ( from 2 sacromeres)

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24
Q

What causes striations in skeletal muscle?

A

Overlapping of thin and thick filaments

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25
Q

What happens when the sacromere shorten?

A

A band - stays the same
H zone- shrinks/ disappears
Z bands - shrink / get closer together
I bands - shrink

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26
Q

What are the binding sites on the thick filament?

A

Actin binding site & Myosin ATPase site

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27
Q

What is the binding site on thin (actin) filaments?

A

Myosin binding site

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28
Q

What are the two regulatory proteins found on thin filament?

A

Tropomyosin - covers myosin binding site

Troponin - holds tropomyosin in place

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29
Q

Cross bridge cycle

A

Myosin heads attach to thin filament

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30
Q

Mechanism of cross bridge cycle

A

Cross bridge forms b/w charged myosin head & actin

  1. Myosin head ratchets pulling actin
  2. Myosin heads releases from actin
  3. Myosin head recharged by ATP
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31
Q

How are myosin heads charged?

A

ATP binds to myosin ATPase site on myosin head ➡️ atp is hydrolyzed ➡️ phosphorylates myosin head charging myosin head

32
Q

Power stroke

A

Myosin head ratchets pulling on thin filament

33
Q

Cross bridge formation

A

Charged myosin head binds to actin ➡️shape change ➡️ phosphate releases

34
Q

What is the role of ca2+ in relaxed muscles?

A

No calcium present therefore tropomyosin covers binding sites

35
Q

What is the role of ca2+ in contracted muscles?

A

Ca2+ present therefore it binds to troponin
- troponin then removes tropomyosin allowing myosin head to bind to actin ➡️pulling ( shortening sarcomere)

36
Q

Action potentials required for ca2+ to be released

True or false

A

True

37
Q

Excitation contraction coupling

A

Turns Ap from motor neuron into Ap in sarcolemma to increase ca2+ concentration allowing for contraction to occur

38
Q

Neuromuscular junction

A

Synapse b/w motor neuron and muscle cell

39
Q

What are the three components in neuromuscular junction?

A
  1. Axon terminal (somatic motor neuron)
  2. Neuromuscular cleft (space)
  3. Motor end plate (muscle cell)
40
Q

Activation of neuromuscular junction mechanism

A
  1. Motor neuron release actin potential
  2. Ca2+ enters voltage gated channel (depolarizing)
  3. Ach releases
  4. Ach binding opens ion channel
  5. Na+ enters
  6. Depolarizing end plate and adjacent muscle plasma membrane
  7. Muscle fiber action potential initiates
  8. Propagated action potential in muscle plasma membrane
  9. Ach is degraded
41
Q

What is found in the motor end plate?

A

Nicotinic Ach receptors

42
Q

What is found in the sarcolemma?

A

Voltage gated na+ channels

43
Q

What are found in transverse (t) tubules?

A

Voltage gated ca2+ channel ➡️triggers ca2+ release channel

44
Q

What are found in sarcoplasmic reticulum?

A

Mechanically gated ca2+ release channel

45
Q

What are the two types of contractions?

A

Isotonic contraction = same tension; movement

Isometric contraction = same length ; no movement

46
Q

Muscle twitch

A

Response to a single electrical stimulus

47
Q

Summation

A

Increased frequency of stimulus producing end twitch before 1st can relax

48
Q

Tetanus

A

Sustained Maximal contraction

49
Q

Increased Ap frequency increases contraction strength

True or false

A

True

50
Q

Graded contractions

A

Generating small to large forces for light vs small loads

51
Q

How are graded contractions created?

A
  1. Increase action potentials frequency
  2. Recruit more motor units
  3. Optimize muscle length
52
Q

Motor units (mu)

A

1 motor neuron + all muscle fibers innervated

53
Q

Large vs small motor units

A

Large = gross motor skills
➡️ less precise (back)

Small = fine motor skills ➡️more precise (fingertips)

54
Q

Less cross bridges = less force

True or false

A

True

55
Q

Sustained contractions

A

Asynchronous activation of motor units
➡️ motor units take turns

56
Q

What are the three muscle fiber types?

A
  1. Fast glycolytic
  2. Fast oxidative glycolytic
  3. Slow oxidative
57
Q

How fast a muscle cell contracts/ twitches depends on….

A
  • rates of cross bridge formation
  • ATPase isoenzymes on myosin head
58
Q

Slow oxidative

A

Aerobic respiration ( need oxygen)
- dense capillaries, lots of myoglobin, numerous mitochondria

Ex) postural muscles

59
Q

Fast glycolytic

A

Anaerobic respiration (lacks oxygen)

  • fewer capillaries, less myoglobin, fewer mitochondria, large glycogen stores

1 glucose ➡️2 atp

Ex) sprinting muscles (fatigue quickly)

60
Q

Fast oxidative glycolytic

A

Aerobic/ anaerobic

  • metabolically intermediate to slow oxidative and fast glycolytic

1 glucose➡️ 36 atp

Ex) endurance muscles

61
Q

What fibers have more mitochondria

A

Slow oxidative

62
Q

atp functions in muscle contraction cause….

A
  1. Bind to myosin releasing from actin ( relaxation)
  2. Phosphorylation of myosin = charged myosin head ( contraction)
  3. Primary active transport = ca2+ into sarcoplasmic reticulum ( relaxation)
63
Q

What is used in the first 8 seconds of exercise?

A

Creatine phosphate

64
Q

After two minutes of experience what is used?

A

Glycolysis

65
Q

What type of exercise promotes weight loss?

A

Mild exercise

66
Q

Golgi tendon organ

A

Senses muscle tension/ contraction

67
Q

What does the golgi tendon organ protect us from

A

Prevents dangerous tension on tendon
- muscle tears / avulsion fracture

68
Q

Muscle spindle

A

Senses muscle length/ stretch

69
Q

The sensor for knee jerk reflex is

A

Muscle spindle organ

70
Q

What does the muscle spindle organ protect us from doing

A

Prevents muscle tears

71
Q

Why during the first two minutes of exercise we are unable to generate atp aerobically?

A

It takes some time for it to increase its spread for the increased demand of atp

72
Q

Where is the muscle spindle located?

A

The belly of muscles

73
Q

What fuels are stored in the body

A

Carbohydrates and fats

74
Q

What form are fuels STORED in the body?

A

Fats = triglycerides

Carbohydrates = glucose 

75
Q

What provides proper control of muscle function

A

A Somatic motor neuron & 2 sensors