Book contents
- Frontmatter
- Contents
- List of contributors
- Preface to the first edition
- Preface to the second edition
- Preface to the third edition
- How to use this book
- Acknowledgements
- List of abbreviations
- Section 1 Clinical anaesthesia
- Section 2 Physiology
- 1 Cellular physiology
- 2 Body fluids
- 3 Haematology and immunology
- 4 Muscle physiology
- 5 Cardiac physiology
- 6 Physiology of the circulation
- 7 Renal physiology
- 8 Respiratory physiology
- 9 Physiology of the nervous system
- 10 Physiology of pain
- 11 Gastrointestinal physiology
- 12 Metabolism and temperature regulation
- 13 Endocrinology
- 14 Physiology of pregnancy
- 15 Fetal and newborn physiology
- Section 3 Pharmacology
- Section 4 Physics, clinical measurement and statistics
- Appendix: Primary FRCA syllabus
- Index
1 - Cellular physiology
from Section 2 - Physiology
- Frontmatter
- Contents
- List of contributors
- Preface to the first edition
- Preface to the second edition
- Preface to the third edition
- How to use this book
- Acknowledgements
- List of abbreviations
- Section 1 Clinical anaesthesia
- Section 2 Physiology
- 1 Cellular physiology
- 2 Body fluids
- 3 Haematology and immunology
- 4 Muscle physiology
- 5 Cardiac physiology
- 6 Physiology of the circulation
- 7 Renal physiology
- 8 Respiratory physiology
- 9 Physiology of the nervous system
- 10 Physiology of pain
- 11 Gastrointestinal physiology
- 12 Metabolism and temperature regulation
- 13 Endocrinology
- 14 Physiology of pregnancy
- 15 Fetal and newborn physiology
- Section 3 Pharmacology
- Section 4 Physics, clinical measurement and statistics
- Appendix: Primary FRCA syllabus
- Index
Summary
Organisation and control
The physiology of the body divides itself into different levels of functional organisation. Natural boundaries define three major levels, those of metabolism, cellular function and organ systems. The control mechanisms at each level form an essential part of the physiology, and direct function towards the ultimate goal of homeostasis. Homeostasis can be defined as maintenance of the composition and properties of extracellular fluid.
Metabolism and metabolic control
Metabolism is a global term encapsulating the mass of biochemical pathways that form the chemical machine providing energy and materials for the maintenance of life. These pathways are controlled at a biochemical level by various factors that determine the rate of metabolic reactions, including:
Chemical parameters affecting reaction rates, e.g. concentration of reactants, temperature, activation energy requirements, presence of catalysts
Enzyme concentration and activity. Factors affecting the rate of enzyme-mediated reactions include substrate concentration, presence of cofactors or coenzymes, and activation or inhibition by reaction products (see allosteric and covalent modulation, below)
The law of mass action and feedback control
At a systemic level metabolism is controlled largely by the endocrine hormones. These substances produce broad physiological changes in the body by exerting multiple effects on cell biochemistry. Some examples of the cellular metabolic effects of hormones are given in Figure PG1.
Cell function and control
Cell function involves both intra- and extracellular processes.
Intracellular functions
Intracellular functions include:
Maintaining the internal milieu
Reproducing DNA
Production of RNA
Repairing cell structures
Synthesis of substances for export
Metabolism of imported substances
Production of chemical energy
Cell motility
- Type
- Chapter
- Information
- Fundamentals of Anaesthesia , pp. 200 - 219Publisher: Cambridge University PressPrint publication year: 2009