PHGY 209 Lecture Notes - Lecture 4: Sodium Chloride, Cytosol, Aquaporin

• School: McGill University
• Department: Physiology
• Course: PHGY 209
• Professor: Melissa A Vollrath

Document Summary

Ion channels: consist of a single protein or clusters of proteins. * ion channels show selectivity based on their diameter and distribution of charges lining the channel. * movement of ions affected by the presence of an electrical gradient; the simultaneous existence of an electrical and concentration gradient for a particular ion is known as electrochemical gradient. Gating ion channels can exist in open or closed state as they undergo conformational changes. Voltage gated ion channels: na+ channels, k+ channels, ca+ channels, cl- channels. The total number of ions that flow through these channels generating ionic current depend upon: the channel conductance, how often the channel opens, how long the channel stays open. Mediated transport: facilitated diffusion, active transport primary active transport, secondary active transport. Net flux proceeds only from region of higher to lower concentration. * hormones may increase the number and/or affinity of transporters in some membranes.