Book contents
- Frontmatter
- Contents
- Preface
- Acknowledgments
- PART I The Head, Ingestion, Utilization and Distribution of Food
- PART II The Thorax and Locomotion
- PART III The Abdomen, Reproduction and Development
- PART IV The Integument, Gas Exchange and Homeostasis
- 16 Integument
- 17 Gaseous exchange
- 18 Excretion and salt and water regulation
- 19 Thermal relations
- PART V Communication
- Taxonomic index
- Subject index
17 - Gaseous exchange
Published online by Cambridge University Press: 05 June 2012
- Frontmatter
- Contents
- Preface
- Acknowledgments
- PART I The Head, Ingestion, Utilization and Distribution of Food
- PART II The Thorax and Locomotion
- PART III The Abdomen, Reproduction and Development
- PART IV The Integument, Gas Exchange and Homeostasis
- 16 Integument
- 17 Gaseous exchange
- 18 Excretion and salt and water regulation
- 19 Thermal relations
- PART V Communication
- Taxonomic index
- Subject index
Summary
Gaseous exchange in insects occurs through a system of internal tubes, the tracheal system, the finer branches of which extend to all parts of the body and may become functionally intracellular in muscle fibers. Thus oxygen is carried directly to its sites of utilization and the blood is not concerned with its transport. In terrestrial insects and some aquatic species, the tracheae open to the outside through segmental pores, the spiracles, which generally have some closing mechanism reducing water loss from the respiratory surfaces. Other aquatic species have no functional spiracles, and gaseous exchange with the water involves arrays of tracheae close beneath the surface of thin, permeable cuticle.
Reviews: Grassé, 1976 – general; Mill, 1985 – general; Miller, 1981a – cockroaches
TRACHEAL SYSTEM
Tracheae
The tracheae are the larger tubes of the tracheal system, running inward from the spiracles and usually breaking up into finer branches, the smallest of which are about 2 μm in diameter. Tracheae are formed by invaginations of the ectoderm and so are lined by a cuticular intima which is continuous with the rest of the cuticle. A spiral thickening of the intima runs along each tube, each ring of the spiral being called a taenidium (Fig. 17.1). The intima consists of outer epicuticle with a protein/chitin layer beneath it. In the taenidia the protein/chitin cuticle is differentiated as mesocuticle or exocuticle. The chitin microfibrils in the taenidia run round the trachea, while between the taenidia they are parallel with the long axis of the trachea.
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- The InsectsStructure and Function, pp. 441 - 477Publisher: Cambridge University PressPrint publication year: 1998
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