5. Equilibrium Potential Flashcards by Jake Hooper

Most areas have a _ charge inside and _ charge outside

Negative, Positive

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What channels are involved with graded potentials and respond to neurotransmitters?

ligand-gated

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What channels are involved with changes in electrical charge (membrane potential) and action potentials?

voltage-gated

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Where do voltage gated channels start to open up?

Initial segment of the axon hillock

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The 2 glial cells in the PNS are _

Satellite cells

Schwann cells

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the 4 glial cells in the CNS are _

oligodendrocytes
astrocytes
microglia
ependymal cells

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ACh receptor is a _ channel

ligand gated

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T/F Gap junctions are involved with electrical synapse

True

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T/F Membrane potential involves single ions

False (multiple)

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_ ions have a higher concentration outside

Na+, Cl-

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_ ions have a higher concentration inside

K+

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K+ is driven out of the cell due to _ and also driven into cell by _

the concentration gradient, electrical attraction (to A-)

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The _ equation solves for equilibrium potential and is _

Nernst

Ex= + or - 60log(Xo/Xi)

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The equilibrium potentials for:
K+
Na+
Cl-
Ca 2+

-90 mV
+60 mV
-70 mV
+90 mV

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_ is the threshold of a typical neuron

-55 mV

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At rest, membrane potential is driven by _

leak channels

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T/F membrane potential is due to K+ and Na+ channels and the Na-K ATPase pump

True

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_ equation is used to calculate membrane potential and is _

Goldman’s equation
Vm= 60 log(P[K]out + P[Na]out + P[Cl-]in)
(P[K]in + P[Na]in + P[Cl-]out)

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Permeability of K:Na:Cl at rest

1 : .01 : .45

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What drug shuts down the Na/K pump and does it affect AP or MP?

Oubane

No, leak channels are still open

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Typical resting membrane potential is _

-70 mV

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Graded potential are also known as _ potentials

local

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Where are ligand gated channels located on neurons?

Cell bodies and dendrites

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For graded potentials, as you move further from the point of origin the strength or amplitude _

Study These Flashcards

decreases

Time constant is defined as _

the time required for voltage in cell to drop 63%

Time constant is dependent on _

Resistance x capacitance (size of membrane)

The _ the time constant, the _ the drop in voltage

larger, slower

Longer time constants allow graded potentials to undergo _, increasing the likelihood of an action potential to fire

temporal summation

When ligand gated channels open, _ flows in causing _

Na, depolarization

T/F Stimulus strength effects amplitude of action potential

False (once threshold hits, it is all or none)

After depolarization, most of the inactivation gates are _, stopping entry of Na+

closed

At resting membrane potential, the activation gate is _, waiting for depolarizing stimulus to arrive due to ligand gated channels

closed

Conductance (g) is defined as _

the ease at which ions flow through voltage gated channels

_ period is where it is impossible to initiate another action potential, because inactivation gates are _

Absolute refractory period | closed

_ period is where a 2nd action potential can be activated but requires a _ stimulus to reach threshhold

Relative refractory period | higher

Ohm's law states voltage=

I X R

H-Huxley model states current=

g(Vm-E)

Driving force for ions is _

(Vm-E)

For cations, when the driving force is +, ions flow _

outward

For cations, when the driving force is -, ions flow _

inward

For anions, when the driving force is +, ions flow _

inward

For anions, when the driving force is -, ions flow _

outward

Tetraethylammonium (TEA) blocks _ resulting in no _ flow

K+ current | outward

Tetrododoxin (TTX) blocks _ resulting in reduced _ flow

Na+ current | inward

Pronase keeps Na+ channels open by _

cleaving off inactivation gate from VG Na+ channels

Permeability of K : Na : Cl after threshold

1 : 20 : .45

Length constant is when _

the voltage decreases over distance by 63% (graded potentials)

Longer length constants have a greater chance to cause an AP due to _

spatial summation

Length constant equation is _

square root of rm/ri

The larger the diameter of a neuron, the _ the resistance

smaller

The speed of AP=

length constant/time constant or (rm/ri)/ (rm x capacitance)

Bigger axons transport signals _ due to a decrease in _

Faster | internal resistance

For bigger axons, _and _ decrease

membrane and internal resistance

For bigger axons, _ increases

capacitance

Myelinated axons transport signals _ _ faster, due to an increase in _ and decrease in _

much, much membrane resistance capacitance

What is the type of conduction where the AP jumps from node to node?

saltutory

Defects in Ca channels cause _ and _

paralysis (hypokalemic) | malignant hyperthermia

Defects in Na channels cause _ and _

Paralysis (hyperkalemic) | Atypical myotonia

Defects in Cl channels cause _ and _

Myotonia | cystic fibrosis

5. Equilibrium Potential Flashcards

(59 cards)