HTHSCI 1H06 Lecture Notes - Lecture 4: Action Potential, Repolarization, Membrane Potential
17 Dec 2017
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Document Summary
Exists across the cell membrane, hence membrane potential. Ionic composition of intracellular and extracellular fluid (na+, k+, ca2+, cl-, proteins) More negative ions on inside of plasma membrane than the outside o. Charge gradient: occurs when there is a difference in electrical charges between ions. Stronger because oppositely charged ions are attracted to each other, same charge ions repel each other. Chemical gradient: occurs when there is a difference in ion concentration, ions are attracted to areas of lower concentration, and therefore move from higher concentration areas to lower concentration areas. Factors involved in maintaining rmp (describe 3) Sodium leaks in more slowly than potassium leaks out. More positive charge leaks out, leaving overall net charge negative. Hyperpolarized: potassium channels open, positive potassium ions rush out of the cell. Depolarized: sodium channels open, positive ions rush into the cell. Ligand: has receptors, correct neurotransmitter must bind for channel to open.
