Chất xúc tác là một chất thúc đẩy tốc độ lên một phản ứng hóa học mà không được thay đổi vĩnh viễn hoặc tiêu thụ riêng của mình. Một enzyme tiêu hóa đóng vai trò như một chất xúc tác, giúp đỡ trong việc tiêu hóa. Tiêu hóa là một quá trình hóa học mà theo đó thực phẩm được chuyển đổi thành các chất đơn giản | LESSON 6 THE HUMAN DIGESTIVE SYSTEM Section I. INTRODUCTION 6-1. GENERAL a. Definition. The human digestive system is a group of organs designed to take in foods initially process foods digest the foods and eliminate unused materials of food items. It is a hollow tubular system from one end of the body to the other end. See figure 6-1. Figure 6-1. The human digestive system. MD0006 6-2 b. Major Organs. The major organs involved in the human digestive system are listed below. They are each discussed later in this lesson. 1 Mouth or oral complex. 2 Pharynx. 3 Esophagus. 4 Stomach. 5 Small intestines and associated glands. 6 Large intestines. 7 Rectum. 8 Anal canal and anus. c. Digestive Enzymes. A catalyst is a substance that accelerates speeds up a chemical reaction without being permanently changed or consumed itself. A digestive enzyme serves as a catalyst aiding in digestion. Digestion is a chemical process by which food is converted into simpler substances that can be absorbed or assimilated by the body. Enzymes are manufactured in the salivary glands of the mouth in the lining of the stomach in the pancreas and in the walls of the small intestine. 6-2. FOODS AND FOODSTUFFS Examples of food items are a piece of bread a pork chop and a tomato. Food items contain varying proportions of foodstuffs. Foodstuffs are the classes of chemical compounds which make up food items. The three major types of foodstuffs are carbohydrates lipids fats and oils and proteins. Food items also contain water minerals and vitamins. Section II. THE SUPRAGASTRIC STRUCTURES 6-3. ORAL COMPLEX The oral complex consists of the structures commonly known together as the mouth. It takes in and initially processes food items. See figure 6-2. MD0006 6-3 Figure 6-2. Anatomy of the oral complex. a. Teeth. 1 A tooth figure 6-3 has two main parts--the crown and the root. A root canal passes up through the central part of the tooth. The root is suspended within a socket called the alveolus of one of .
