Farmasevtika instituti farmakologiya va klinik farmatsiya kafedrasi

Transpulmonary Pressure. 
Finally, note in Figure 37-2 the difference between the alveolar 
pressure and the pleural pressure. This is called the 
transpulmonary pressure
. It is the pressure 
difference between that in the alveoli and that on the outer surfaces of the lungs, and it is a measure of 
the elastic forces in the lungs that tend to collapse the lungs at each instant of respiration, called the 
recoilpressure
. 
Compliance of the Lungs 
The extent to which the lungs will expand for each unit 
increase in transpulmonary pressure (if enough time is allowed to reach equilibrium) is called the 
lung 
compliance
. The total compliance of both lungs together in the normal adult human being averages 
about 200 milliliters of air per centimeter of water transpulmonary pressure. That is, every time the 
transpulmonary pressure increases1 centimeter of water, the lung volume, after 10 to 20 seconds, will 
expand 200 milliliters.

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General Principles of Gastrointestinal Function— Motility, Nervous Control, and Blood 
Circulation. 
 
The alimentary tract provides the body with a continual supply of water, electrolytes, vitamins, 
and nutrients. To achieve this requires (1) movement of food through the alimentary tract; (2) secretion 
of digestive juices and digestion of the food; (3) absorption of water, various electrolytes, vitamins, 
and digestive products; (4) circulation of blood through the gastrointestinal organs to carry away the 
absorbed substances; and (5) control of all these functions by local, nervous, and hormonal systems. 
Figure 62-1 shows the entire alimentary tract. Each part is adapted to its specific functions: some to 
simple passage of food, such as the esophagus; others to temporary storage of food, such as the 
stomach; and others to digestion and absorption, such as the small intestine. In this chapter, we discuss 
the basic principles of function in the entire alimentary tract; in the following chapters, we discuss the 
specific functions of different segments of the tract.