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7 - The respiratory system

Published online by Cambridge University Press:  05 June 2012

C. Ross Ethier
Affiliation:
University of Toronto
Craig A. Simmons
Affiliation:
University of Toronto
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Summary

The function of the respiratory system is to exchange O2 and CO2 with the blood. To understand this system from a bioengineering viewpoint, we will first discuss the gross anatomy of the lungs and their associated structures, and then discuss the mechanics of breathing.

Gross anatomy

We divide the respiratory system into two subsystems: the conducting airways and the associated structures.

The conducting airways and pulmonary vasculature

The conducting airways form a fantastically complex branching tree designed to transport air efficiently into the alveoli, the smallest air-filled structures in the lung where blood/gas exchange takes place. Air enters through the mouth or nose then passes through (in order): the pharynx (the throat), the larynx (the voice box), and the trachea (the large tube passing down the neck). The trachea splits to form two bronchi (singular: bronchus), each of which feed air to one of the lungs (Fig. 7.1, color plate).

Each bronchus splits to form bronchioles, which, in turn, split to form smaller bronchioles, and so on (Fig. 7.2). After about 16 levels of branching, we reach the terminal bronchioles, which are the smallest structures that have a purely air-conducting function, that is, in which essentially no blood/gas exchange takes place (Fig. 7.3). In adult lungs, the structures distal to the terminal bronchioles consist of several generations of respiratory bronchioles, alveolar ducts and alveolar sacs, which collectively are known as the acinus; this is where the gas exchange occurs (Fig. 7.4).

Type
Chapter
Information
Introductory Biomechanics
From Cells to Organisms
, pp. 282 - 331
Publisher: Cambridge University Press
Print publication year: 2007

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References

Vander, A. J., Sherman, J. H. and Luciano, D. S.. Human Physiology: The Mechanisms of Body Function, 4th edn (New York: McGraw-Hill, 1985).Google Scholar
Weibel, E. R.. The Pathway for Oxygen: Structure and Function in the Mammalian Respiratory System (Cambridge, MA: Harvard University Press, 1984).Google Scholar
Weibel, E. R.. Morphometry of the Human Lung (New York: Academic Press, 1963).CrossRefGoogle Scholar
Fawcett., D. W.Bloom and Fawcett: A Textbook of Histology (Philadephia, PA: W. B. Saunders, 1986).Google Scholar
Schraufnagel, D. E. (ed.) Electron Microscopy of the Lung (New York: Marcel Dekker, 1990), p. 298.Google Scholar
Weibel, E. R. and Gomez, D. M.. Architecture of the human lung. Use of quantitative methods establishes fundamental relations between size and number of lung structures. Science, 137 (1962), 577–585.CrossRefGoogle ScholarPubMed
Ochs, M., Nyengaard, J. R., Jung, A., Knudsen, L., Voigt, M.et al. The number of alveoli in the human lung. American Journal of Respiratory and Critical Care Medicine, 169 (2004), 120–124.CrossRefGoogle ScholarPubMed
Vawter, D. L. and Humphrey., J. D. Elasticity of the lung. In Handbook of Bioengineering, ed. Skalak, R. and Chien, S.. (New York: McGraw-Hill, 1987), pp.24.1–24.20.Google Scholar
Clements, J. A.. Surface phenomena in relation to pulmonary function. Physiologist, 5 (1962), 11–28.Google ScholarPubMed
Bachofen, H., Hildebrandt, J. and Bachofen, M.. Pressure–volume curves of air-and liquid-filled excised lungs: surface tension in situ. Journal of Applied Physiology, 29 (1970), 422–431.CrossRefGoogle ScholarPubMed
Sapoval, B., Filoche, M. and Weibel, E. R.. Smaller is better – but not too small: a physical scale for the design of the mammalian pulmonary acinus. Proceedings of the National Academy of Sciences USA, 99 (2002), 10411–10416.CrossRefGoogle Scholar
Sobin, S. S., Fung, Y. C., Tremer, H. M. and Rosenquist, T. H.. Elasticity of the pulmonary alveolar microvascular sheet in the cat. Circulation Research, 30 (1972), 440–450.CrossRefGoogle ScholarPubMed
Christoforides, C., Laasberg, L. H. and Hedley-Whyte, J.. Effect of temperature on solubility of O2 in human plasma. Journal of Applied Physiology, 26 (1969), 56–60.CrossRefGoogle ScholarPubMed
Austin, W. H., Lacombe, E., Rand, P. W. and Chatterjee, M.. Solubility of carbon dioxide in serum from 15 to 38 ℃C. Journal of Applied Physiology, 18 (1963), 301–304.CrossRefGoogle ScholarPubMed
Cooney., D. O.Biomedical Engineering Principles (New York: Marcel Dekker, 1976).Google Scholar
Wiebe, B. M. and Laursen, H.. Human lung volume, alveolar surface area, and capillary length. Microscopy Research and Technique, 32 (1995), 255–262.CrossRefGoogle ScholarPubMed
Capen, R. L., Latham, L. P. and Wagner, W. W. Jr.Comparison of direct and indirect measurements of pulmonary capillary transit times. Journal of Applied Physiology, 62 (1987), 1150–1154.CrossRefGoogle ScholarPubMed
Staub, N. C. and Schultz, E. L.. Pulmonary capillary length in dogs, cat and rabbit. Respiration Physiology, 5 (1968), 371–378.CrossRefGoogle ScholarPubMed
Caro, C. G., Pedley, T. J., Schroter, R. C. and Seed, W. A.. The Mechanics of the Circulation (Oxford: Oxford University Press, 1978).Google Scholar
Weibel, E. R., Federspiel, W. J., Fryder-Doffey, F., Hsia, C. C., Konig, M.et al. Morphometric model for pulmonary diffusing capacity. I. Membrane diffusing capacity. Respiration Physiology, 93 (1993), 125–149.CrossRefGoogle ScholarPubMed
Huang, W., Yen, R. T., McLaurine, M. and Bledsoe, G.. Morphometry of the human pulmonary vasculature. Journal of Applied Physiology, 81 (1996), 2123–2133.CrossRefGoogle ScholarPubMed
Popel, A. S.. A finite-element model of oxygen diffusion in the pulmonary capillaries. Journal of Applied Physiology, 82 (1997), 1717–1718.CrossRefGoogle ScholarPubMed
Guyton, A. C.. Textbook of Medical Physiology, 4th edn (Philadelphia, PA: W. B. Saunders, 1971).Google Scholar
Milhorn, H. T. Jr. and Pulley, P. E. Jr.A theoretical study of pulmonary capillary gas exchange and venous admixture. Biophysical Journal, 8 (1968), 337–357.CrossRefGoogle ScholarPubMed
Frank, A. O., Chuong, C. J. and Johnson, R. L.. A finite-element model of oxygen diffusion in the pulmonary capillaries. Journal of Applied Physiology, 82 (1997), 2036–2044.CrossRefGoogle ScholarPubMed
Merrikh, A. A. and Lage, J. L.. Effect of blood flow on gas transport in a pulmonary capillary. Journal of Biomechanical Engineering, 127 (2005), 432–439.CrossRefGoogle Scholar
Cussler, E. L.. Diffusion: Mass Transfer in Fluid Systems, 2nd edn (New York: Cambridge University Press, 1997).Google Scholar
Felici, M., Filoche, M. and Sapoval, B.. Diffusional screening in the human pulmonary acinus. Journal of Applied Physiology, 94 (2003), 2010–2016.CrossRefGoogle ScholarPubMed
Weibel, E. R., Sapoval, B. and Filoche, M.. Design of peripheral airways for efficient gas exchange. Respiratory Physiology and Neurobiology, 148 (2005), 3–21.CrossRefGoogle ScholarPubMed
Owens, D. R., Zinman, B. and Bolli, G.. Alternative routes of insulin delivery. Diabetic Medicine, 20 (2003), 886–898.CrossRefGoogle ScholarPubMed
Grotberg, J. B.. Respiratory fluid mechanics and transport processes. Annual Review of Biomedical Engineering, 3 (2001), 421–457.CrossRefGoogle ScholarPubMed
White, F. M.. Viscous Fluid Flow, 2nd edn (New York: McGraw-Hill, 1991).Google Scholar
Spielman, L. A.. Particle capture from low-speed laminar flows. Annual Review of Fluid Mechanics, 9 (1977), 297–319.CrossRefGoogle Scholar
Radford, E. P. Jr. Recent studies of mechanical properties of mammalian lungs. In Tissue Elasticity, ed. Remington, J. W.. (Washington, DC: American Physiological Society, 1957), pp. 177–190.Google Scholar
Green, E. L. (ed.) for the Jackson Laboratory. Biology of the Laboratory Mouse, 2nd edn (New York: Dover, 1966).Google Scholar
Dohm, M. R., Hayes, J. P. and Garland, T. Jr.The quantitative genetics of maximal and basal rates of oxygen consumption in mice. Genetics, 159 (2001), 267–277.Google ScholarPubMed

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