Equivalent Circuit of a Neuron

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the role of the cations and anions in a neuron?

They cause the membrane to be a capacitor.

They provide electrical resistance.

They prevent the flow of ions across the membrane.

They are responsible for creating potential differences. (correct)

What does resistance (R) in electrical circuits refer to?

The flow of charge measured in amperes.

The ability to generate charge.

The difference in electric potential measured in volts.

The opposition to the movement of current. (correct)

How can the properties of a neuron's electrical activity be modeled?

As an equivalent circuit consisting of resistors, capacitors, and generators. (correct)

Using a circuit with only resistors.

With batteries and resistors only.

With capacitors and generators only.

What is the significance of the Goldman equation in neuronal activity?

It calculates the change in permeability and individual ion currents. Signup and view all the answers

What does the equation $V = Q/C$ represent?

The relationship between charge and capacitance producing a potential difference. Signup and view all the answers

What component of the neuron functions as a capacitor?

The phospholipid bilayer of the membrane. Signup and view all the answers

Why is the potential difference important in neuronal function?

It provides the energy to move ions across membranes. Signup and view all the answers

What does capacitance indicate in the context of a neuron's membrane?

The ability to store an electric charge. Signup and view all the answers

What does Ohm’s law state about the relationship between electric current, voltage, and resistance?

Electric current is directly proportional to voltage and inversely proportional to resistance. Signup and view all the answers

What is the primary difference between conductance and resistance?

Conductance is the inverse of resistance. Signup and view all the answers

What does the term 'leaky capacitor' refer to in the context of cell membranes?

A capacitor that has ion channels allowing charge to conduct. Signup and view all the answers

How is the net K+ current expressed in relation to membrane voltage and Nernst potential?

iK = γK × (Vm − EK) Signup and view all the answers

In terms of conductance, how is Ohm's law reformulated?

V = I / G Signup and view all the answers

What role does the K+ concentration gradient play across the membrane?

It generates a chemical force that drives K+ movement. Signup and view all the answers

What unit measures conductance in an electrical circuit?

Siemens Signup and view all the answers

Which equation represents the relationship between unitary current, membrane voltage, and unitary conductance?

iK = Vm x γK Signup and view all the answers

What is the Nernst potential for K+ when [X]o is 155 mM and [X]i is 4 mM?

-91 mV Signup and view all the answers

What does the equivalent circuit of a neuron represent?

The passive electrical properties of neuronal membranes Signup and view all the answers

Which component of the equivalent circuit acts as a generator?

Na/K pump Signup and view all the answers

How does the presence of ion channels affect the behavior of the plasma membrane?

It allows the membrane to become a leaky capacitor Signup and view all the answers

What is true about the ionic current in relation to the Nernst potential?

Ionic current is the product of conductance and the difference between membrane voltage and Nernst potential. Signup and view all the answers

What role does the Na-K pump play in neuronal circuits?

It maintains the ionic gradients that are essential for action potentials. Signup and view all the answers

In the context of the equivalent circuit, which component stores electrical energy?

Capacitor Signup and view all the answers

Which equation correctly describes the relationship between ionic current, conductance, and membrane potential?

iK = gK × (Vm − EK) Signup and view all the answers

Study Notes

Equivalent Circuit of a Neuron

The equivalent circuit represents a neuron's electrical properties using resistors, capacitors, and batteries.
The membrane is a capacitor due to the phospholipid bilayer separating the cytoplasm and extracellular fluid.
The voltage across a capacitor is determined by the equation V = Q/C, where Q is the charge and C is the capacitance.
Ion channels act as resistors, allowing charge to flow and contributing to the membrane's conductance.
Ohm's law explains the relationship between current (I), voltage (V), and resistance (R): V = I x R, or V = I/G, where G is conductance.
The Nernst potential, denoted as EK for potassium, represents the electromotive force of a potassium channel.
The ionic current through a potassium channel is calculated as iK = gK × (Vm − EK), where gK is the potassium conductance and Vm is the membrane voltage.
The Na/K pump is represented as a generator in the equivalent circuit.
The equivalent circuit can be used to calculate resting potential, Vm; single or total currents; single or total conductance; and battery potential.

Components of the Equivalent Circuit

Plasma membrane: Acts as a capacitor, storing electrical charge.
Channels: Act as resistors, allowing ion flow across the membrane.
Na/K pump: Functions as a generator, maintaining the ionic gradients.

Studying That Suits You

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

Description

This quiz covers the electrical properties of neurons as represented by equivalent circuits. Key concepts include the roles of capacitors, resistors, and the relationships defined by Ohm's law and the Nernst potential. Test your understanding of how these principles apply to neural function and signaling.