TABLE OF CONTENTS The respiratory tract is a very important organ of first contact for most environmental exposures. Some cause damage to the respiratory tract, others merely use it as a route to access other parts of the body. An adequate understanding of the toxicology of the respiratory tract requires some basic knowledge of the anatomy and physiology of this organ system and an outline is presented early in this chapter. An indication of the frequency of occupational lung disease is provided with reference to data from specialist reports in Britain. Reference to chemical interactions at a molecular level is made especially in relation to asthma. Practical aspects such as health surveillance are also outlined.
In common with other organisms, humans need a supply of oxygen for the metabolic processes of respiration and consequently a system for disposing of the carbon dioxide so produced. In unicellular and simple multicellular microorganisms, this can be achieved by diffusion alone. Complex organisms have evolved specialised tissues and structures to perform a respiratory function. In humans, the respiratory tract can be thought of in two parts, a gas-conducting and a gas-exchange system. This works in alliance with the cardiovascular system to perfuse tissues with oxygen and remove carbon dioxide.
The nose is the organ of the respiratory tract that is first exposed to inhaled agents (Figure 14.1). It is provided with a convoluted surface over the turbinates or conchae. Its main channel is to the nasopharynx and...
