ABSTRACT
To understand asthma in children, a thorough knowledge of the development and physiology of the lung from fetal life through childhood to adulthood is essential. Knowledge of the stages of the development of the airway and the relationships between airway size and lung gas volume is needed to interpret clinical signs in normal and asthmatic children. It is also needed to interpret lung function data from children, along with familiarity with the methodologies for measuring lung function. To look after sick asthmatic children, a sound basis in respiratory physiology is especially important. Recognizing early signs of respiratory failure and implementing appropriate strategies require an appreciation of the basic mechanisms of moving gas in and out of the lung and gas exchange within the lung. For physicians training during the last decade, it has not been easy to gain an appropriately in-depth knowledge of these processes owing to the current research emphasis on cellular and molecular aspects of asthma. For non-physician asthma researchers, know-
are frequently used in outcome assessments of research studies. This chapter will summarize important elements in the development of the lung, and techniques for objectively assessing lung and airway function in infants and children.
