ICPP - Resting Membrane Potential Flashcards Preview

CJ: UoL Medicine Semester One (ESA1) > ICPP - Resting Membrane Potential > Flashcards

Flashcards in ICPP - Resting Membrane Potential Deck (13):
1

What is the membrane potential?

The magnitude of an electrical charge that exists across a plasma membrane.

2

What are membrane potentials measured in?

Millivolts (mV)

3

True or false - some animal cells have negative membrane potentials at rest?

True - they all do.

4

Which type of animal cell has the smallest negative membrane potential?

Erythrocytes

5

Which cell has the most negative resting membrane potential?

Skeletal muscle cell

6

How is cell membrane potential measured?

Use a fine glass pipette (microelectrode) which can penetrate cell membrane. Tip is less than 1 micrometer and filled with a conducting solution (KCl). Connect a voltmeter to it and measure potential.

7

What are the two "minimum essentials" required for a membrane potential to be established?

ASYMMETRIC DISTRIBUTION of ions across the plasma membrane and SELECTIVE ION CHANNELS in the plasma membrane.

8

Give three properties of ion channels.

SELECTIVITY (for one/a few ion species), GATING (pore can open or close by conformational change), RAPID ION FLOW (always down gradient).

9

True or false - when the chemical and electrical gradients for K+ are equal and opposite, there will be no movement of K+ and a negative charge across the membrane?

True!

10

Given the intracellular and extracellular concentrations of K+, what can you calculate using the Nernst equation?

The membrane potential at which K+ will be in equilibrium.

11

True or false - a very large amount of K+ must move across the membrane to set up the voltage?

False - less than 1% of ions.

12

Why do erythrocytes have such a low resting membrane potential?

They have virtually no selectivity for K+.

13

Why does cardiac muscle have a resting membrane potential that is less negative than Ek (K+ equilibrium)?

Not perfectly selective for K+.

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