Physiology Of Muscle Contraction Flashcards

1
Q

In skeletal 4 Ca bind to?

A

Troponin C, but in heart 3 Ca, changes conformation, shuts off Tn1 tropomyosin- troponin leaves F-actin groove unmasks the myosin binding site on actin

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2
Q

Troponin I is a marker for?

A

Total muscle breakdown

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3
Q

Cardiac TnI is marker for?

A

Myocardial infarct

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4
Q

Macro molecular contraction?

A

Contraction depends on myosin head binding to think actin filaments at specific binding sites.

Otherwise blocked by tropomysoin

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5
Q

Cross bridge cycle?

A
  1. To allow myosin head to let go, release ADP, require ATP to allow myosin to let go of actin
  2. Myosin head cleaves ATP
  3. Myosin binds actin, when moved tropomysoin out of way (ca was present)
  4. Power stroke
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6
Q

What is rigor mortis?

A

ATP is needed to pump ca in sarcoplasmic reticulum.

ATP deleted

Myosin stuck to actin,

Rigor mortis ends when muscle tissue degrades after 3 days

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7
Q

How do you store ATP?

A

Creatinine is stored in muscle after phosphorylation

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8
Q

How to get energy from. Muscles?

A

Creatine phosphate (in mitochondria) gives a phosphate group to ADP.

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9
Q

Creatine phospho kinase does what?

A

Adds phosphate to creatine

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10
Q

Phosphokinase is a marker of?

A

Muscle destruction

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11
Q

Creatinine is?

A

Breakdown product of creatine, marker for kidney function

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12
Q

Depolarisation allows influx of calcium?

A

Active nicotine cells acetylcholine receptor, net inward current.

Causing depolarisation spread via T-Tubules

Local action potentials trigger Ca2+ efflux from terminal cisternae
Across membrane of sarcoplasmic reticulum
into the fibre cytoplasm

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13
Q

SERCA does what?

A

Puts ca back in the SR

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14
Q

Ryanodine receptor does what?

A

Releases ca from SR, triggered by voltage sensor on ca channel

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15
Q

Frequent APs cause complete tetany because?

A

Insufficient Ca resequestration so summation of contraction

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16
Q

Slow twitch are?

A

Type 1 “red” oxidative small diameter

High myoglobin, many mitochondria

17
Q

Fast twitch have?

A

Type 2 white
Non oxidative wide diameter
Lower myoglobin
Energy requires from glycolysis

18
Q

Which muscle fibres are fatigue resistance?

A

Slow

19
Q

Soleus muscle has composition?

A

80% type slow

20% type IIA

20
Q

Vastus lateralis for running has composition?

A

Mixture of type I, IIA, IIX

21
Q

Long distance runner have?

A

Type 1 predominantly

22
Q

In type I what type of fuel as storage?

A

Triglycerides

23
Q

In Type II fibres the fuel for storage?

A

Creatine phosphate

Glycogen

24
Q

Motor unit is?

A

A single alpha motor neuron and muscle fibres it innervates

25
Q

Isometric?

A

Generates variable force while length of muscle remains unchanged

26
Q

Isotonic?

A

Generates a constant force while the length of muscle changes

27
Q

Eccentric contraction?

A

Force during muscle elongation

28
Q

Size principle?

A

as the initial isometric contraction occurs:

more and more motor units are recruited starting with smaller ones and progressively adding larger ones

29
Q

Lower motor neuron disease?

A

Weakness

Muscle atrophy

30
Q

Upper motor neurone disease?

A

Spasticity, hypertonia

31
Q

Lack of patellar reflex is called?

A

Westphals sign

32
Q

Muscle spindle consists of how many intrafusal fibres?

A

3-12

33
Q

Sensors from muscle spindle are called?

A

Type 1a and Type 2

34
Q

Tendon reflex aim?

A

Protection from overloading

35
Q

Tendon reflex has how many synapses?

A

2

36
Q

Eccentric and concentric contraction?

A

Eccentric- force during muscle elongation

Concentric- force during contraction

37
Q

Size principle?

A

Always start with small motor unit, as its going through feedback mechanisms, recruit bigger motor units to generate force

38
Q

Absence of Westphalia sign means there is?

A

Receptor damage
Femoral nerve damage
Peripheral nerve disease