Book contents
- Frontmatter
- Contents
- Acknowledgements
- Definitions, abbreviations and conventions
- 1 Introduction and overview
- 2 Ions in solution
- 3 Diffusion in free solution
- 4 Diffusion within a membrane
- 5 Membranes, channels, carriers and pumps
- 6 Membrane equivalent circuits
- 7 Voltage-sensitive channels: the membrane action potential
- 8 The propagated action potential
- 9 Synaptic potentials
- 10 Membrane noise
- Appendices
- Suggested further reading
- Index
Appendices
Published online by Cambridge University Press: 25 October 2011
- Frontmatter
- Contents
- Acknowledgements
- Definitions, abbreviations and conventions
- 1 Introduction and overview
- 2 Ions in solution
- 3 Diffusion in free solution
- 4 Diffusion within a membrane
- 5 Membranes, channels, carriers and pumps
- 6 Membrane equivalent circuits
- 7 Voltage-sensitive channels: the membrane action potential
- 8 The propagated action potential
- 9 Synaptic potentials
- 10 Membrane noise
- Appendices
- Suggested further reading
- Index
Summary
APPENDIX 1. Units and numbers
When electrophysiologists measure currents, voltages cr concentrations they measure physical quantities that are the same physical quantities that a physicist or chemist might deal with. In order to characterize precisely these entities it is necessary to specify two things:
(1) The quality of the units, and
(2) The numerical size of the units used.
Dimensions
We shall deal first with the quality of physical units and this quality is called the dimension. Natural scientists have agreed on a number of different systems of units. The two most widely used systems are the c.g.s. system in which the fundamental units are:
(L) length – centimetre
(M) mass – gram
(T) time – second
and then there is the MKS system with the fundamental units of:
(L) length – metre
(M) mass – kilogram
(T) time – second
The latter is the so-called rationalized MKS system, more closely related to the International System of Units (SI), which is coming steadily into universal use.
In Table 1 we give some physical units that are used in the two systems. More detailed information is available in Quantities, Units, and Symbols, a report by the Symbols Committee of the Royal Society, 2nd edn, 1975, and in Units of Measurement, Preprint from the Geigy Scientific Tables, 7th edn, 1968 (Basle, Switzerland: Geigy).
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- The Biophysical Basis of Excitability , pp. 259 - 468Publisher: Cambridge University PressPrint publication year: 1985