Bioelec II - Prof Yin Lecture II Sept 8 2010 Bioelectricity...

Info iconThis preview shows pages 1–13. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Prof. Yin Lecture II Sept. 8, 2010 Bioelectricity Goldman Equation Suppose we have three ions, Na + , K + AND Cl- what is the equation for space charge neutrality ? J K + + J Na + = J Cl- If the membrane has three permeable ions, Na, K and Cl, the potential can be derived similarly as before and results in + + + + = − + + − + + o Cl i Na i K i Cl o Na o K m Cl P Na P K P Cl P Na P K P q KT V ] [ ] [ ] [ ] [ ] [ ] [ ln Note: If the permeability of one ion is much, much higher than for the other ions, the membrane potential is close to the Nernst potential for that ion Goldman Equation • If nothing stimulates the membrane, the RMP will not change • Stimuli – Ionic change – Permeability change – Electrical signal – Chemical signal – Mechanical event Excitability of a Membrane Excitability of a Membrane Excitatory and Inhibitory Electrical Stimuli Response of Membrane to Electrical Stimuli Rheobase – signal of infinitely long duratio required for activatiton Chronaxy – duration of activating signal twice the rehobase Ion channels Permeability and hence electrical signals in cells are modulated by ion channels. Ion channels are specialized membrane proteins . • The genes of most ion channel proteins have been cloned • The structure of some ion channels are known • Diverse types to suit physiological functions Ion Channel Structure Membrane lipid bilayer is not permeable to water or ions. Ion concentrations inside and outside of cells are different - results in membrane potential Na + Membrane Extracellular side Cytoplasmic side Ion channels are membrane spanning proteins allowing ions to flow across membrane Opening and closing of ion channels controls membrane potential - proper sequence causes action potential H 2 O Ion Channel Structure Crystal Structure: Kcsa K Channels Roderick MacKinnon Doyle et al. (1998) Science 280:69~77. A dynamic structure undergoing thermal fluctuations (atomic trembling)! Ion Channel Structure From Neuron to Brain, Fourth Edition John G. Nicholls, A. Robert Martin, Bruce G. Wallace, and Paul A. Fuchs Common features: • Membrane spanning domains • Pore • Intracellular loops Proposed 3-D structure Ion channels Permeability and hence electrical signals in cells are modulated by ion channels....
View Full Document

This note was uploaded on 02/14/2012 for the course NUBITRY 3304 taught by Professor Various during the Spring '01 term at Albertus Magnus.

Page1 / 39

Bioelec II - Prof Yin Lecture II Sept 8 2010 Bioelectricity...

This preview shows document pages 1 - 13. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online