Physiology 3140A Lecture Notes - Lecture 11: Electric Field, Conformational Change, Potassium Channel

• School: Western University
• Department: Physiology
• Course: Physiology 3140A
• Professor: John Di Guglielmo

Document Summary

Typical range (electrophysiology) mv (10-3) na (10-9 a), pa (10-12 a) M (106 ), g (109 ) ns (10-9 s), ps (10-12 s) Direction of current = movement of positive charges from high to low electrical potential (voltage) In biological tissues, electrical activities are carried by ions (not electrons as in metals) Ions = cations (+) and anions (-: cations: na+, k+, ca2+, mg2, anions: cl-, hco3. Current directly proportional to voltage and inversely proportional to resistance. Sakmann & neher 1970s: single ion channel recording. ~ 5nm in width: protein ion channels. Gating of channels sensor for gating: electrical (voltage-gated ion channels) e. g. most na+ channels, l- and t-type ca2+ channels, chemical (ligand-gated ion channels) Nachr, ampar, nmdar & gabaar: mechanical (mechanically gated ion channels) *note: cell membrane is so thin acts as a capacitor; stores charge. *note: the sensor and gate are actually on separate domains.