MD137 Lecture 2: Resting Membrane Potential
21 Questions
2 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary ion that contributes to the resting membrane potential due to its greater permeability?

  • Cl-
  • Ca2+
  • K+ (correct)
  • Na+

The concentration gradients for K+ and Na+ across the cell membrane create which type of potential?

  • Diffusion potential (correct)
  • Chemical potential
  • Thermal potential
  • Hydrostatic potential

What occurs at equilibrium concerning ion movement across the membrane?

  • Concentration forces are neutralized by electrical forces (correct)
  • No ions move across the membrane
  • Electrical forces exceed concentration forces
  • Ions move in only one direction

What factor pulls K+ ions into the cell despite their net diffusion outwards?

<p>Electrochemical gradient (D)</p> Signup and view all the answers

Which of the following best describes the resting membrane potential?

<p>The voltage when ion movement is at electrochemical equilibrium (C)</p> Signup and view all the answers

What does the Nernst equation primarily calculate?

<p>Equilibrium potential for an ion (C)</p> Signup and view all the answers

What is the equilibrium potential for potassium ion (K+) based on the content?

<p>-93 mV (A)</p> Signup and view all the answers

Which ion is primarily responsible for establishing the resting membrane potential (RMP)?

<p>K+ (B)</p> Signup and view all the answers

What is the total contribution of the Na+/K+ pump to the resting membrane potential (RMP)?

<p>6-8 mV (D)</p> Signup and view all the answers

What factor does the GHK equation take into account that the Nernst equation does not?

<p>Permeability of multiple ions (A)</p> Signup and view all the answers

How does the mobility of Na+ affect the resting membrane potential?

<p>It slightly affects RMP as it is relatively impermeable. (B)</p> Signup and view all the answers

What is the major role of the Na+/K+ pump in maintaining the cellular environment?

<p>To maintain ionic gradients (C)</p> Signup and view all the answers

What primarily affects the resting membrane potential (RMP) of a neuron?

<p>The unequal distribution of ions across the cell membrane (C)</p> Signup and view all the answers

Why does the resting membrane potential not equal the equilibrium potential for K+?

<p>Because the membrane has a significant permeability to Na+. (D)</p> Signup and view all the answers

Why is the resting membrane potential of nerve cells typically around -70mV?

<p>The presence of large negatively charged proteins inside the cell (D)</p> Signup and view all the answers

Which ion has a greater permeability that contributes to resting membrane potential?

<p>K+ (D)</p> Signup and view all the answers

What role does the Na+/K+ electrogenic pump play in resting membrane potential?

<p>It maintains the unequal distribution of ions necessary for RMP (A)</p> Signup and view all the answers

What concept relates to the voltage difference across a cell membrane?

<p>Bioelectricity (A)</p> Signup and view all the answers

Luigi Galvani's experiments demonstrated a relationship between which two types of electricity?

<p>Biological electricity and artificial electricity (D)</p> Signup and view all the answers

Which factors are NOT involved in the formation of the resting membrane potential?

<p>Equal ion concentration on both sides of the membrane (D)</p> Signup and view all the answers

What can be a dangerous effect of potassium in a patient's bloodstream?

<p>Inhibition of Na+/K+ pump function (A)</p> Signup and view all the answers

Flashcards

Unequal Ion Distribution

The difference in concentration of ions (like sodium and potassium) across the cell membrane. This difference is crucial for generating the resting membrane potential.

Resting Membrane Potential (RMP)

The electrical potential difference across the cell membrane when the cell is at rest. It's typically negative inside the cell compared to the outside.

Greater permeability to K+

The cell membrane is more permeable to potassium ions (K+) than to sodium ions (Na+). This means potassium can move across the membrane more easily.

Diffusion Potential

The electrical potential difference created by the movement of ions down their concentration gradient across a semipermeable membrane.

Signup and view all the flashcards

Equilibrium Potential

The specific potential difference across the cell membrane at which the net movement of an ion is zero. It's reached when the concentration gradient and electrical gradient for the ion are balanced.

Signup and view all the flashcards

Bioelectricity

The electrical activity found within living organisms, particularly in nerve and muscle cells.

Signup and view all the flashcards

Biopotentials

The voltage differences across cell membranes, caused by the unequal distribution of ions.

Signup and view all the flashcards

Transmembrane Potential

The electrical potential difference across the cell membrane, specifically referring to the voltage difference between the inside and outside of the cell.

Signup and view all the flashcards

Membrane Permeability

The ease with which specific ions can pass through the cell membrane. The cell membrane is more permeable to K+ than Na+.

Signup and view all the flashcards

Large Indiffusible Anions

Negatively charged molecules trapped inside the cell, contributing to the negative RMP.

Signup and view all the flashcards

Na+/K+ Electrogenic Pump

A protein pump that actively moves 3 sodium ions (Na+) out of the cell and 2 potassium ions (K+) into the cell, contributing to the RMP and requiring ATP.

Signup and view all the flashcards

Nernst Equation

A mathematical equation that calculates the equilibrium potential for a specific ion across a membrane. It considers the ion's concentration gradient and charge.

Signup and view all the flashcards

What determines RMP?

The RMP is primarily determined by the permeability of the membrane to different ions, especially potassium (K+) and sodium (Na+). The ion with the highest permeability has the greatest influence on the RMP.

Signup and view all the flashcards

Sodium-Potassium Pump

A protein pump that actively transports 3 sodium ions (Na+) out of the cell for every 2 potassium ions (K+) pumped in. This maintains the concentration gradients of these ions.

Signup and view all the flashcards

Role of Sodium-Potassium Pump in RMP

While the pump maintains the ion gradients crucial for RMP, it only contributes a small amount (around 6-8mV) to the overall RMP. Diffusion of ions across the membrane plays the primary role.

Signup and view all the flashcards

GHK Equation

A more complex equation that takes into account the permeability of the membrane to different ions and their movements across it. This provides a more accurate prediction of RMP than the Nernst Equation.

Signup and view all the flashcards

RMP is NOT just K+ diffusion

The resting membrane potential is not solely determined by the passive diffusion of potassium ions. It also depends on the relative permeability of the membrane to other ions, particularly sodium.

Signup and view all the flashcards

Study Notes

Course Information

  • Course: MD137
  • Course description: Introduction to Physiology
  • Lecturer: Leo Quinlan
  • Lecturer email: [email protected]
  • Academic year: 2024-2025

Lecture 2: Resting Membrane Potential (RMP)

  • Topic: Resting Membrane Potential (RMP)
  • Content:
    • RMP is the electrical potential difference across the cell membrane of a neuron when it is at rest.
    • RMP is typically around -70mV.
    • Key factors that contribute to the formation of RMP:
      • Unequal distribution of ions across the membrane
      • Greater membrane permeability to potassium (K+) ions than sodium (Na+) ions
      • Large negatively charged, impermeable anions inside the cell
      • Sodium-potassium pump (Na+/K+ pump)
    • The Na+/K+ pump actively maintains the ion gradients across the membrane.

Glial cell types in the CNS

  • Microglial cells - immune function
  • Oligodendrocytes - myelin sheath production
  • Astrocytes - neuronal support, blood-brain barrier
  • Ependymal cells - blood-CSF barrier

Learning Outcomes

  • Define resting membrane potential (RMP)
  • Describe the components that form RMP
  • Explain the formation of the nerve's RMP
  • Explain the reason for RMP being near -70mV
  • Explain how potassium can be lethal

Exitable Central Neurons

  • Central neurons exhibit various wave patterns
  • Specific frequencies are denoted as alpha, beta, theta, and delta waves.

Exitable Peripheral Neurons

  • Graphs show characteristic oscillations of excitability in peripheral neurons.

Bioelectricity

  • Electrical charges exist in cells, especially nerve and muscle cells.
  • Biopotentials are transmembrane potentials, resulting from voltage differences across cell membranes.
  • Luigi Galvani's experiments demonstrated the electrical nature of nerve impulses in frogs.

Measuring RMP

  • Measuring RMP
  • Using a voltmeter and microelectrodes
  • Measuring the voltage diffrence between the outside of the cell and inside the cell.

Membrane Potential Changes

  • Depolarization - membrane potential becomes less negative
  • Repolarization - membrane potential returns to resting level
  • Hyperpolarization - membrane potential becomes more negative

Bioelectricity - Equilibrium

  • Equal distribution of charges across a cellular membrane.

What contributes to RMP Generation

  • Unequal ion distribution across cell membranes
  • Higher membrane permeability to K+ ions than Na+ ions
  • Presence of large, impermeable anions inside the cell
  • Sodium-potassium pump (Na+/K+ pump)

Typical ion concentrations in neurons

  • Table detailing typical ion concentrations inside and outside a neuron's axon

Membrane Permeability (K+ vs. Na+)

  • Explain the relative differences in permeability of the membrane to K⁺ vs Na⁺ ions.
  • K⁺ is more permeable.

Equilibrium Potential of K+ (EK)

  • Derive EK using the Nernst equation.
  • Use data to confirm.

Importance of the Na+/K+ Pump

  • Maintain ion concentration gradients.
  • Contribute about 6-8mV to the overall RMP

Potentials in real neurons

  • Passive K⁺ distribution is not the entire cause of membrane potential
  • Membranes are relatively, not absolutely, impermeable to Na⁺
  • Na+/K+ pump plays as major contributor

GHK Equation

  • More comprehensive model for calculating membrane potential (Em)
  • Considers all ion permeabilities

Questions

  • Net driving force on K⁺ ions
  • Net driving force on Na⁺ ions
  • Ion diffusion direction
  • Impact of altered extracellular ion concentrations on membrane potential (Vm).

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

2024-2025 Physiology Lecture Notes (University of Galway)

Description

This quiz covers the resting membrane potential (RMP) as discussed in Lecture 2 of the MD137 Introduction to Physiology course. It explores the electrical potential difference across the cell membrane of neurons at rest, key factors contributing to RMP, and the role of the Na+/K+ pump. Additionally, it touches on glial cell types in the CNS.

More Like This

Neuronal Cell Biology (2)
16 questions

Neuronal Cell Biology (2)

HearteningEnglishHorn avatar
HearteningEnglishHorn
Neuronal Membrane and Resting Membrane Potential
10 questions

Neuronal Membrane and Resting Membrane Potential

NoteworthyBerkelium avatar
NoteworthyBerkelium
Brain and Behaviour: Resting Membrane Potential
6 questions

Brain and Behaviour: Resting Membrane Potential

IlluminatingDallas avatar
IlluminatingDallas
Use Quizgecko on...
Browser
Open
Browser
Browser