Orderly and clear summary of chapter 3 "voltage-dependent membrane permeability" what is discussed during the neuroscience lectures. With this summary you will save a lot of time. I passed this course with a 8,2. Good luck :)
Chapter 3 -- voltage-dependent membrane permeability
Overview
First rapid and transient (tijdelijk) rise in Na (depolarization) than slow and long rise in
K repolarization and even hyperpolarization)
Ion currents across nerve cell membranes
Opening of Na channels is very important and therefore well researched.
The voltage-clamp method: control of the membrane potential and simultaneously
(gelijktijdig) measure the underlying permeability changes.
This provides information needed to define the ion permeability of the membrane at
any level of membrane potential (or voltage)
Voltage-clamp method: because it controls or
clamps membrane potential (or voltage) at any
level:
1. Internal electrode measure membrane
potential (or voltage) (Vm)
2. Voltage clamp compares membrane
potential (or voltage) with the desire
(command) potential (or voltage)
3. When Vm is different from common potential (or voltage), the clamp injects
current into the axon through a second electrode. This causes the Vm to
become the same as the command potential (or voltage)
4. Current flowing back into the axon and thus cross the membrane can be
measured here
Two types of voltage-dependent ion currents
Whether (of) neuronal membrane have voltage-
dependent permeabilities?
Membrane potential (or voltage) change negatively = hyperpolarization
Capacitive current is negative. Very little current flow of Na (Na channels are
closed)
Membrane potential (or voltage) change positively = depolarization
Capacitive current is first positive. Before Na channel open first a small
amount of Na flow out the cell
Then slowly rising negative (early inward current). Before Na channel open
first a small amount of Na flow out of the cell. When impulse is bigger than +52
mV no Na out of the cell anymore because of bigger permeability
Then become positive (late outward current). Large amount of
Na flow in the cell
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller biomedicalsciencesvu. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $3.19. You're not tied to anything after your purchase.
