Timothy J. Bradley
- Published in print:
- 2008
- Published Online:
- April 2010
- ISBN:
- 9780198569961
- eISBN:
- 9780191728273
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198569961.001.0001
- Subject:
- Biology, Animal Biology
Water is fundamental to life and to the maintenance of an appropriate environment for physiological functions at the molecular, cellular, and organismal level. Water balance is also the principal ...
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Water is fundamental to life and to the maintenance of an appropriate environment for physiological functions at the molecular, cellular, and organismal level. Water balance is also the principal mechanism of volume regulation in animals. The physical properties of water have profound effects on all biological structures and their function. Animal Osmoregulation has three main themes. The first deals with the physical properties of water, and its interactions with proteins, lipids, and biological membranes. Solutes affect the activity of water and thus the magnitude of the gradients driving water movement through osmosis. The distribution and transport of water in biological systems depends therefore on the properties of solutes, their distribution, and their transport. The second theme involves a detailed physical description of osmosis. This is followed by an explanation of the significance of osmotic regulation in animals inhabiting a wide variety of environments. Examples are explored for marine, freshwater, and terrestrial animals. A broad phylogenetic array of animals is discussed. Thirdly, the book deals with membranes as compartmental barriers. By definition, osmosis occurs through semi-permeable membranes. Membranes also, however, play a fundamental role in energy storage, energy transduction, solute transport, and sensory physiology. This volume approaches animal osmoregulation from the perspective of the physical laws that influence the structure of biological systems. It extends these concepts to explore the diversity of adaptations in the animal kingdom that deal with osmotic challenges in a variety of environments.Less
Water is fundamental to life and to the maintenance of an appropriate environment for physiological functions at the molecular, cellular, and organismal level. Water balance is also the principal mechanism of volume regulation in animals. The physical properties of water have profound effects on all biological structures and their function. Animal Osmoregulation has three main themes. The first deals with the physical properties of water, and its interactions with proteins, lipids, and biological membranes. Solutes affect the activity of water and thus the magnitude of the gradients driving water movement through osmosis. The distribution and transport of water in biological systems depends therefore on the properties of solutes, their distribution, and their transport. The second theme involves a detailed physical description of osmosis. This is followed by an explanation of the significance of osmotic regulation in animals inhabiting a wide variety of environments. Examples are explored for marine, freshwater, and terrestrial animals. A broad phylogenetic array of animals is discussed. Thirdly, the book deals with membranes as compartmental barriers. By definition, osmosis occurs through semi-permeable membranes. Membranes also, however, play a fundamental role in energy storage, energy transduction, solute transport, and sensory physiology. This volume approaches animal osmoregulation from the perspective of the physical laws that influence the structure of biological systems. It extends these concepts to explore the diversity of adaptations in the animal kingdom that deal with osmotic challenges in a variety of environments.
Timothy J. Bradley
- Published in print:
- 2008
- Published Online:
- April 2010
- ISBN:
- 9780198569961
- eISBN:
- 9780191728273
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198569961.003.0011
- Subject:
- Biology, Animal Biology
The first step in maintaining homeostasis involves sensing any changes in the environment and in the internal physiological condition. All cells are able to sense changes in cytoplasmic volume. ...
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The first step in maintaining homeostasis involves sensing any changes in the environment and in the internal physiological condition. All cells are able to sense changes in cytoplasmic volume. Increased cell volume can be countered through the transport of solutes out of the cell. The movement of solutes drives osmotic water movement and thus cell volume reduction. Cell shrinkage can be countered through the uptake of solutes or through the production of small osmotically active molecules from large organic molecules. Sensory determination of osmotic concentration is usually indirect. Changes in cell volume can be used by cells such as neurons to determine changes in osmotic concentration in the surrounding fluids. In many organisms, sodium ions are the principal cations in the blood and changes in sodium concentration parallel changes in blood volume. Examples of homeostatic regulation of volume and osmotic concentration are provided for the best-studied systems, namely insects and mammals.Less
The first step in maintaining homeostasis involves sensing any changes in the environment and in the internal physiological condition. All cells are able to sense changes in cytoplasmic volume. Increased cell volume can be countered through the transport of solutes out of the cell. The movement of solutes drives osmotic water movement and thus cell volume reduction. Cell shrinkage can be countered through the uptake of solutes or through the production of small osmotically active molecules from large organic molecules. Sensory determination of osmotic concentration is usually indirect. Changes in cell volume can be used by cells such as neurons to determine changes in osmotic concentration in the surrounding fluids. In many organisms, sodium ions are the principal cations in the blood and changes in sodium concentration parallel changes in blood volume. Examples of homeostatic regulation of volume and osmotic concentration are provided for the best-studied systems, namely insects and mammals.
Timothy J. Bradley
- Published in print:
- 2008
- Published Online:
- April 2010
- ISBN:
- 9780198569961
- eISBN:
- 9780191728273
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198569961.003.0004
- Subject:
- Biology, Animal Biology
If differences in the activity of water exist across a semi-permeable membrane, movement of water by osmosis will result. Cells, and indeed entire organisms, must therefore regulate the activity of ...
More
If differences in the activity of water exist across a semi-permeable membrane, movement of water by osmosis will result. Cells, and indeed entire organisms, must therefore regulate the activity of water in order to maintain appropriate cell and body volume. The body plans of animals vary substantially between phyla, yet the laws governing osmotic flux remain the same. The key to the regulation of the activity of water is the regulation of solutes in body and cellular compartments. Certain types of solutes are termed compatible solutes because they can occur in bodily fluids in relatively high concentrations yet they do not denature proteins or disrupt membrane structure.Less
If differences in the activity of water exist across a semi-permeable membrane, movement of water by osmosis will result. Cells, and indeed entire organisms, must therefore regulate the activity of water in order to maintain appropriate cell and body volume. The body plans of animals vary substantially between phyla, yet the laws governing osmotic flux remain the same. The key to the regulation of the activity of water is the regulation of solutes in body and cellular compartments. Certain types of solutes are termed compatible solutes because they can occur in bodily fluids in relatively high concentrations yet they do not denature proteins or disrupt membrane structure.
Steven L. Chown and Sue W. Nicolson
- Published in print:
- 2004
- Published Online:
- September 2007
- ISBN:
- 9780198515494
- eISBN:
- 9780191705649
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198515494.003.0004
- Subject:
- Biology, Animal Biology
This chapter reviews the mechanisms involved in water gain and loss, and osmoregulation of individual insects, as well as the expansion of this aspect of insect physiology to new levels. Cuticular ...
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This chapter reviews the mechanisms involved in water gain and loss, and osmoregulation of individual insects, as well as the expansion of this aspect of insect physiology to new levels. Cuticular and respiratory water loss are covered in detail as is the controversial issue of the role of discontinuous gas exchange in the water economy of insects. At the cellular level, the transporters of Malpighian tubules and the peptide hormones controlling them are currently an active topic of research and are reviewed in detail. At the population level, desiccation resistance is being studied in a variety of insects in both hot and cold environments, and in laboratory populations of Drosophila which have undergone selection for increased desiccation resistance. Water balance physiology is one area where the links between mechanism and pattern are being made from the level of laboratory selection to large-scale comparative studies at continental scales. This level of integration, especially for Drosophila, is fast becoming a benchmark for studies on other organisms.Less
This chapter reviews the mechanisms involved in water gain and loss, and osmoregulation of individual insects, as well as the expansion of this aspect of insect physiology to new levels. Cuticular and respiratory water loss are covered in detail as is the controversial issue of the role of discontinuous gas exchange in the water economy of insects. At the cellular level, the transporters of Malpighian tubules and the peptide hormones controlling them are currently an active topic of research and are reviewed in detail. At the population level, desiccation resistance is being studied in a variety of insects in both hot and cold environments, and in laboratory populations of Drosophila which have undergone selection for increased desiccation resistance. Water balance physiology is one area where the links between mechanism and pattern are being made from the level of laboratory selection to large-scale comparative studies at continental scales. This level of integration, especially for Drosophila, is fast becoming a benchmark for studies on other organisms.
Steven L. Chown and Sue Nicolson
- Published in print:
- 2004
- Published Online:
- September 2007
- ISBN:
- 9780198515494
- eISBN:
- 9780191705649
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198515494.001.0001
- Subject:
- Biology, Animal Biology
This book provides a modern, synthetic overview of interactions between insects and their environments from a physiological perspective that integrates information across a range of approaches and ...
More
This book provides a modern, synthetic overview of interactions between insects and their environments from a physiological perspective that integrates information across a range of approaches and scales. It shows that evolved physiological responses at the individual level are translated into coherent physiological and ecological patterns at larger, even global scales. This is done by examining in detail the ways in which insects obtain resources from the environment, process these resources in various ways, and turn the results into energy which allows them to regulate their internal environment as well as cope with environmental extremes of temperature and water availability. The book demonstrates that physiological responses are not only characterized by substantial temporal variation, but also show coherent variation across several spatial scales. At the largest, global scale, there appears to be substantial variation associated with the hemisphere in which insects are found. Such variation has profound implications for patterns of biodiversity as well as responses to climate change, and these implications are explicitly discussed. The book provides a novel integration of the understanding gained from broad-scale field studies of many species and the more narrowly focused laboratory investigations of model organisms. In so doing, it reflects the growing realization that an integration of mechanistic and large-scale comparative physiology can result in unexpected insights into the diversity of insects.Less
This book provides a modern, synthetic overview of interactions between insects and their environments from a physiological perspective that integrates information across a range of approaches and scales. It shows that evolved physiological responses at the individual level are translated into coherent physiological and ecological patterns at larger, even global scales. This is done by examining in detail the ways in which insects obtain resources from the environment, process these resources in various ways, and turn the results into energy which allows them to regulate their internal environment as well as cope with environmental extremes of temperature and water availability. The book demonstrates that physiological responses are not only characterized by substantial temporal variation, but also show coherent variation across several spatial scales. At the largest, global scale, there appears to be substantial variation associated with the hemisphere in which insects are found. Such variation has profound implications for patterns of biodiversity as well as responses to climate change, and these implications are explicitly discussed. The book provides a novel integration of the understanding gained from broad-scale field studies of many species and the more narrowly focused laboratory investigations of model organisms. In so doing, it reflects the growing realization that an integration of mechanistic and large-scale comparative physiology can result in unexpected insights into the diversity of insects.
