Physiology 3140A Lecture Notes - Lecture 23: Hydrophile, Phosphatidylserine, Lipid Bilayer

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

Document Summary

Lecture 23 lipid-derived chemical mediators, pkc, calcium. Regulation of resting ca++ levels in the cell. Transient opening of ca2+ channels leads to increases in local ca2+ concentrations in cytosol, and activation of ca2+ -dependent proteins in cell. Increases in calcium inside the cell are local events (cid:498)calcium sparks(cid:499) Increases in calcium levels and opening of calcium channels are kept localized and increases are seen near the area where the receptor opened. Increase in calcium is not homogenous: local changes of calcium levels and biological events occur in the area with the increase = activation of calcium dependent proteins or enzymes, changes in cytoskeleton, etc. For ca2+ to act as an intracellular signal, cytosolic ca2+ must be maintained at low levels. Antiport that does not use metabolic energy (no atp: sodium electrochemical gradient is used to export calcium out of the cell, cell pumps calcium out and sodium in (going in two different concentrations)