CELL-MEMBRANES - BARRIERS, REGULATORS AND TRANSDUCERS

The concept of the cell membrane as a physical barrier has been progre ssively revised over the past 50 years to produce a model of a homeost atic regulatory system. Homeostatic feedback systems involve control a nd feedback transducers, with error detecting systems. It is, therefor e, interesting to see how far the control of membrane fluidity, cell v olume and ion composition can be interpreted in this way especially in epithelial systems. An attempt is made to consider the systems involv ed in extracellular, intracellular and stored calcium. When membranes are analysed in this way it is possible to identify questions about th e extent to which cell regulation and cell transport might be in confl ict, and how specific some membrane functions might be. These can then be related to the study of various adaptations to environmental stres ses. (C) 1998 Elsevier Science Inc. All rights reserved.