February 23 - February 23 Cations: positive charged Anions:...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
February 23 Cations: positive charged Anions: negative charged Can measure difference in charge across a membrane with microelectrode Membrane potential: difference in charge across membrane When resting and then gets message from another neuron there is a reversal of polarity caused by sodium (Na+) ions and potassium ions (K+) o Sodium entering cells before potassium leaves cell so inside cell becomes very positive Threshold level: -55 mV o After reaching threshold level it fires the message Action potential spreads as a wave of depolarization down the axon Voltage-Gated: sodium and potassium channels, needs a certain change in potential in order to open up o Closed when membrane is polarized (charges are separated) o When inactivated cannot stimulate it no matter what Inactivated Na channel-refractory to stimulus Action potential: messages that travel along neurons, as action potential sgo through voltage-gates depolarizes it more Propagation of actin potential only goes in one direction
Background image of page 1

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

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/25/2011 for the course BIO 101 taught by Professor Pytel during the Winter '11 term at Union College.

Page1 / 2

February 23 - February 23 Cations: positive charged Anions:...

This preview shows document pages 1 - 2. Sign up to view the full document.

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