Book contents
- Frontmatter
- Contents
- Preface to the second edition
- Preface to the first edition
- How to use this book
- 1 Introduction to physiological calculation: approximation and units
- 2 Quantifying the body: interrelationships amongst ‘representative’ or ‘textbook’ quantities
- 3 Energy and metabolism
- 4 The cardiovascular system
- 5 Respiration
- 6 Renal function
- 7 Body fluids
- 8 Acid–base balance
- 9 Nerve and muscle
- Appendix A Some useful quantities
- Appendix B Exponents and logarithms
- References
- Notes and Answers
- Index
2 - Quantifying the body: interrelationships amongst ‘representative’ or ‘textbook’ quantities
Published online by Cambridge University Press: 06 July 2010
- Frontmatter
- Contents
- Preface to the second edition
- Preface to the first edition
- How to use this book
- 1 Introduction to physiological calculation: approximation and units
- 2 Quantifying the body: interrelationships amongst ‘representative’ or ‘textbook’ quantities
- 3 Energy and metabolism
- 4 The cardiovascular system
- 5 Respiration
- 6 Renal function
- 7 Body fluids
- 8 Acid–base balance
- 9 Nerve and muscle
- Appendix A Some useful quantities
- Appendix B Exponents and logarithms
- References
- Notes and Answers
- Index
Summary
In order to develop a quantitative understanding of the workings of the body it is helpful to have at one's fingertips some representative, ‘standard’ or ‘textbook’ physiological quantities. Indeed, it is commonplace that students be expected to learn such figures for blood volume, cardiac output, respiratory minute volume, glomerular filtration rate, etc. These may well be those of a ‘standard 70-kg man’ or someone rather like him – young, healthy, not too fat, male and, as such, never pregnant or lactating (see Notes and Answers, note 2A). The purpose of this chapter is to illustrate how certain representative quantities may be made meaningful and so worth memorizing. Whether students try to learn every such quantity brought to their attention or as few as possible (neither extreme being desirable), the effort is most rewarding if those quantities are made meaningful in particular contexts and integrated into a general quantitative picture of bodily function. At this stage readers might care to list all those physiological quantities that they either know or feel they ought to know, and to specify contexts in which they think the knowledge would illuminate discussion of physiological topics.
One difficulty for learning is that physiological quantities vary from person to person and from moment to moment. At the same time, many people find it easiest to learn definite numbers or definite normal limits, finding the ill-defined ranges of reality too slippery to stay in the mind.
- Type
- Chapter
- Information
- Physiology by NumbersAn Encouragement to Quantitative Thinking, pp. 18 - 26Publisher: Cambridge University PressPrint publication year: 2000