Nerve Physiology Flashcards

1
Q

At rest, is potential positive or negative intracellular vs extracellular?

A
Intracellular = negative 
Extracellular = positive
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2
Q

At rest what does the sodium potassium ATP pump do

A

Pumps out three sodium ions while pumping in 2 potassium ions

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3
Q

And rest what is the difference in sodium and potassium concentration intracellularly versus extracellularly

A

More sodium outside and more potassium inside

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4
Q

Effect of decreased temperature on velocity, amplitude and latency

A

Decreased velocity, increased latency, increased amplitude for focal cooling and decreased amplitude for generalized cooling

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5
Q

What does a decrease in temperature do to sodium channel gates?

A

Delays opening and closing of gates.

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6
Q

Orthodromic versus antidromic

A

Orthodromic is in the direction of physiologic conduction and antidromic is opposite direction of physiologic conduction

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7
Q

Orthodromic of motor and sensory fibers

A

Motor is away from spinal cord and sensory is toward spinal cord

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8
Q

Antidromic of motor and sensory fibers

A

Motor is toward spinal cord and sensory is away from spinal

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9
Q

MEPPs vs EPP vs MUAP

A

Miniature endplate potentials (MEPP) = spontaneous release of quanta at rest
Endplate potential (EPP) = multiple MEPP summate to make EPP
Motor Unit Action Potential (MUAP) = When EPP is high enough, it generates a MUAP

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10
Q

What is the safety factor?

A

EPP’s amplitude is much larger than needed to create an action potential which allows time for Ach storage compartments to replenish

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11
Q

Safety factor depends on what 2 factors

A

Quantal content and quantal response

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12
Q

What is the quantal content

A

of Ach quanta release with each nerve depolarization

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13
Q

What is quantal response

A

Ability of Ach receptors to respond to Ach

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14
Q

What 2 main proteins make up skeletal muscle fibers

A

Actin and myosin

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15
Q

Basic unit of a muscle myofibril

A

Sarcomere

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16
Q

Z-lines

A

Length of sarcomere

17
Q

H zone

A

Actin to actin length

18
Q

I zone

A

Myosin to myosin

19
Q

A band

A

Length of myosin filament

20
Q

What happens to sarcomere length, Z lines, H zone, A band, I band during contraction?

A

Sarcomere length - decreases as Z lines move closer to each other.
H zone - gets smaller as actin filaments get closer.
A band - Stays the same because myosin length doesn’t change during contraction.
I band - gets smaller as myosin filaments get closer

21
Q

What is the only section of the sarcomere that does not change in size with contraction

A

A band

22
Q

Action potentials penetrate through the muscle through the _________

A

T-tubules

23
Q

Calcium binds to what to cause muscle contraction

A

Troponin-tropomyosin complex

24
Q

What is exposed when calcium binds to muscle filaments

A

Actin active sites

25
Q

What allows muscle relaxation

A

ATP pumps that pump calcium out