CLA204H1 Chapter Notes - Chapter 4: Cannabinoid, Brainstem, Professional Agrologist
Document Summary
The membrane potential is the difference in electrialcharge between the inside and the outside of the cell. To record a neuron s membrane potential, it is necessary to position the tip of one electrode inside the neuron and the tip of another electrode outside the neuron in the extracellular fluid. The intracellular electrodes are called microelectrodes; their tips are less than one-thousandth of a millimeter in diameter. This steady membrane potential of about 70 mv is called the neuron s resting potential. In its resting state, with the 70 mv charge built up across its membrane, a neuron is said to be polarized. The first of the two homogenizing factors is random motion. The second factor that promotes the even distribution of ions is electrostatic pressure. Any accumulation of charges, positive or negative, in one area tends to be dispersed by the repulsion among the like charges in the vicinity and the attraction of opposite charges concentrated elsewhere.
