L4: NEURAL CONDUCTION & SYNAPTIC TRANSMISSION
1. Resting Membrane Potential - Microelectrodes are thin electrodes – one is placed inside the neuron
and the other tip in the extracellular fluid
- The resting potential is -70mV
- It exists because + and – ions are distributed unequally on the two sides
of the neural membrane.
- There are 4 factors that determines the ionic distribution of the resting
- Ions in solution are in random motion so there can be an accumulation
Random Motion of a particular class of ions in one area
- This increases the probability that random motion moves ions out of the
area because there are more ions available to leave or not move more
ions into the area because there are fewer ions available to come in.
Electrostatic Pressure - Like charges repel and opposite charges attract, thus, electrostatic
pressure disperses any accumulation of + or – charges in an area.
Differential Permeability of - Ions pass through membrane at special pores called ion channels. When
Membrane neurons are at rest the membrane is resistant to K+/Cl- ions