Farmasevtika instituti farmakologiya va klinik farmatsiya kafedrasi

Movements Caused by the Muscularis Mucosae and Muscle 
A principal function of the ileocecal valve is to prevent backflow of fecal contents from the colon 
into the small intestine. As shown in Figure 63-4, the ileocecal valve itself protrudes into the lumen of 
the cecum and therefore is forcefully closed when excess pressure builds up in thececum and tries to 
push cecal contents backward against the valve lips.
Other Autonomic Reflexes That Affect Bowel Activity 
Aside from the duodenocolic, gastrocolic, gastroileal, enterogastric, and defecation reflexes that 
have been discussed in this chapter, several other important nervous reflexes also can affect the overall 
degree of bowel activity. 
Metabolism of Carbohydrates, and Formation of Adenosine Triphosphate 
The next few chapters deal with metabolism in the body—the chemical processes that make it 
possible for the cells to continue living. It is not the purposeof this textbook to present the chemical 
details of all the various cellular reactions, because this lies in the discipline of biochemistry. Instead, 
these chapters are devoted to (1) a review of the principal chemical processes of the cell and (2) an 
analysis of their physiologic implications, especially the manner in which they fit into the overall body 
homeostasis.
Release of Energy from Foods, and the Concept of ―Free Energy‖ 
Most of the chemical reactions in the cells are aimed at making the energy in foods available to 
the various physiologic systems of the cell. For instance, energy is required for muscle activity, 
secretion by the glands, maintenance of membrane potentials by the nerve and muscle fibers, synthesis 
of substances in the cells, absorption of foods from the gastrointestinal tract, and many other functions. 
Coupled Reactions. 
All the energy foods—carbohydrates, fats, and proteins—can be oxidized in the 
cells, and during this process, large amounts of energy are released.