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Metabolism, Temperature, and Ventilation

  1. Jacopo P. Mortola1,
  2. Michael Maskrey2

Published Online: 1 OCT 2011

DOI: 10.1002/cphy.c100008

Comprehensive Physiology

Comprehensive Physiology

How to Cite

Mortola, J. P. and Maskrey, M. 2011. Metabolism, Temperature, and Ventilation. Comprehensive Physiology. 1:1679–1709.

Author Information

  1. 1

    Department of Physiology, McGill University, Montreal, Canada

  2. 2

    Department of Anatomy and Physiology, University of Tasmania, Hobart, Australia

Publication History

  1. Published Online: 1 OCT 2011

Abstract

In mammals and birds, all oxygen used (inline imageo2) must pass through the lungs; hence, some degree of coupling between inline imageo2 and pulmonary ventilation (inline imagee) is highly predictable. Nevertheless, inline imagee is also involved with CO2 elimination, a task that is often in conflict with the convection of O2. In hot or cold conditions, the relationship between inline imagee and inline imageo2 includes the participation of the respiratory apparatus to the control of body temperature and water balance. Some compromise among these tasks is achieved through changes in breathing pattern, uncoupling changes in alveolar ventilation from inline imagee. This article examines primarily the relationship between inline imagee and inline imageo2 under thermal stimuli. In the process, it considers how the relationship is influenced by hypoxia, hypercapnia or changes in metabolic level. The shuffling of tasks in emergency situations illustrates that the constraints on inline imagee-inline imageo2 for the protection of blood gases have ample room for flexibility. However, when other priorities do not interfere with the primary goal of gas exchange, inline imagee follows metabolic rate quite closely. The fact that arterial CO2 remains stable when metabolism is changed by the most diverse circumstances (moderate exercise, cold, cold and exercise combined, variations in body size, caloric intake, age, time of the day, hormones, drugs, etc.) makes it unlikely that inline imagee and metabolism are controlled in parallel by the condition responsible for the metabolic change. Rather, some observations support the view that the gaseous component of metabolic rate, probably CO2, may provide the link between the metabolic level and inline imagee. © 2011 American Physiological Society. Compr Physiol 1:1679-1709, 2011.