Lecture 2: Membrane Potentials Flashcards

1
Q

Most of the bodies solutes are ___ and thus carry a ____ charge

A

Ions
Net Electrical

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2
Q

Cause ions to move across cell membranes

A

Gradients

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3
Q

Separation of ___ takes place across the membrane

A

Charge

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4
Q

The electrical potential is called the

A

Membrane potential

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5
Q

Membrane potentials are determined by 3 factors:
1. _____ of ions on the inside and outside
of the cell.
2. ____ of the cell membranes to those
ions through ion channels
3. Activity of _____ that maintain
[ion] across the membranes

A

Concentration
Permeability
Electrogenic pumps

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6
Q

All cells have different concentrations of ___ across the membrane (esp Na+, K+, Cl-), as well as ____ charged proteins to which the cell membrane is ____

A

Ions
Negatively
Impermeable

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7
Q

Typical resting potential is ___ mV

A

70

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8
Q

Resting membrane potential: Constant membrane potential in:
• ____ cells
•____ cells at rest

A

Nonexcitable
Excitable

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9
Q

Minus sign means inside of cell is ___ compared to outside

A

Negative

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10
Q

Ions responsible for generating resting potential are the cations ___ and ___, as well as____ anions.

A

Na+ and K+
intracellular

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11
Q

Na+ greater concentration in the ___, moderate permeability
• K+ higher concentration in the ___, high permeability
• A- only in the ___, no permeability

A

ECF
ICF
ICF

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12
Q

The Na+–K+ pump: __ Na+ out of the
cell for every 2___K+ in
•Inside becomes ___ compared to
outside
•Primary role of the pump is to actively
___ Na+ and K+ concentration
gradients

A
  1. 2
    NEGATIVE
    MAINTAIN
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13
Q

In a cell that is permeable to just one ion, the membrane potential that exactly opposes the concentration gradient is called the _____
or E(ion)

A

equilibrium potentiaL

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14
Q

The greater the ____ of
the plasma membrane for a
given ion, the greater the
tendency for that ion to drive
the membrane potential toward
the ion’s own ____
potential

A

Permeability
Equilibrium

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15
Q

At rest, a membrane is 50-75
times as permeable to
___, therefore ____
influences resting membrane
potential to a greater extent

A

Potassium
Potassium

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16
Q

Nerve and muscles cells are excitable cells and can change their resting membrane potential to produce ______

A

Electrical signals

17
Q

Neurons use signals to receive, process, initiate, and transmit ____
◦ Muscle cells use signals initiate ___ ___

A

Messages
Muscle contractions

18
Q

Changes in membrane potential are brought about by ___ movements
• Net inward flow of +ve ions compared with resting state → _____
• Net outward flow of +ve ions compared with resting state →_____

A

Ion
Depolarization
Hyperpolarization

19
Q

______: membrane becomes less polarized than at resting potential
_______: membrane returns to resting potential after having been depolarized
_____: membrane becomes more polarized than at resting potential

A

Depolarization
Repolarization
Hyperpolarization

20
Q

Recall that ions can only cross membranes via specific ____

A

Channels

21
Q

Types of gated channels:
1. ____ gated
2. _____ gated
3. ____ gated
4. _____ gated

A

Voltage
Chemically
Mechanically
Thermally

22
Q

2 basic forms of electrical signals
• ____ potentials
• _____ potentials

A

Graded
Action

23
Q

_____ potentials
Local changes in membrane potential
•Occur in a small, specialized region of excitable cell membranes
•Usually produced by specific triggering events that causes gated ion channels to open in a
specialized region of the membrane generally chemically- or mechanically–gated

A

Graded

24
Q

The magnitude of this
graded potential is related to
the magnitude of the
____ event
• The _____ the trigger, the
larger the _____
graded potential
• The ____ the duration of
the triggering event, the
longer the duration of the
_____ potential

A

Triggering
Stronger
Depolarizing
Longer
Graded

25
Q

Current can be ___ across membrane
• Because of this leak, the local current
progressively _____ with increasing
distance from origin
• Graded potentials have limited
signaling ____

A

Lost
Decreases
Distance

26
Q

Graded potentials can sum to
initiate ______

A

Action potentials

27
Q

The ____ equation is used to calculate the resting membrane potential that results from the contribution of all ions that can cross the membrane

A

GHK - Goldman-Hodgkin-Katz equation