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M2M test 4 > Action Potentials > Flashcards

Flashcards in Action Potentials Deck (11)
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1
Q

action potential threshold

A

voltage point that once exceeded initiates the all or nothing response of neurons firing. Inward flow of Na, outward flow of K+

2
Q

Na_v gates

A

at resting inactivation gate is open and activation is closed. Depolarization both are open. Repolarization activation gate is open, inactivation is closed

3
Q

positive-feedback of rising phase

A

rising voltage due to Na channels causes the opening of adjacent Na channels, which further increases Vm

4
Q

Na/K pump during AP

A

Na/K pump is responsible is called upon to restore proper ion balance. If poisoned axon will fill with Na and lose K. pump is always on, doesn’t go into mega mode or anything

5
Q

Refactory period

A

after AP, axon cannot produce another one for a few milliseconds. Divided into absolute refractory and relative refractory. Results from inactivation gate closer of Na channel requiring time to reopen after repolarization. Even with a stimulus, Na activation gate may open, but inactivation stays closed. thus no AP

6
Q

internal resistance

A

high Ri => smaller spread of current

7
Q

membrane resistance

A

higher Rm => larger spread of current

8
Q

membrane capacitance

A

higher Cm => smaller spread of current

9
Q

Axons are poor cables

A

Rm is low, Ri is high, Cm is high, lambda is 1mm

10
Q

diameter and conduction velocity

A

larger diameter, slower conductance (temp and pain receptors smaller than skin mechanoreception)

11
Q

Myelination and conduction

A

increase conduction speed by requiring less Na channels to fire