Mastication

Digestion begins in the mouth. A brain reflex triggers the flow of saliva when we see or think about food. Saliva moistens the food while the teeth chew it up and make it easier to swallow. The digestive enzyme in saliva, starts to break down starch into simpler sugars before the food leaves the mouth. The nervous pathway involved in salivary excretion requires stimulation of receptors in the mouth, sensory impulses to the brain stem, and parasympathetic impulses to salivary glands.

Swallowing your food happens when the muscles in your tongue and mouth move the food into your pharynx. The pharynx is the passageway for food and air. A small flap of skin called the epiglottis over the pharynx prevents food from entering the trachea and thus choking.

POST-TEXT ASSIGMENTS

Exercise 7. Answer the following questions to the text:

1. When does the digestive process begin?

2. How many processes occur during digestion?

3. What is the difference between mechanical and chemical digestions?

4. What is the function of the smooth muscles?

5. What nutrients come from food during absorption?

6. What is the role of saliva in mastication?

7. What is the function of the enzyme?

8. How does the process of swallowing occur?

Exercise 8. Translate the following word combinations into English:

Початок травного процесу, виділяти слину, давати енергію клітинам тіла, розщеплювати жири на жирні кислоти і гліцерин, хімічне травлення, поглинати більш ефективно, розподілити по всьому тілу, рефлекторно викликати потік слини, вимагати стимуляції рецепторів, запобігти потрапляння в трахею, зволожити їжу, прохід для їжі та повітря.

Exercise 9. Match the terms with their definitions:

1. Proteins   2. fats   3. starches   4. enzymes   5. digestion   6. mastication   7. chocking   8. swallowing

a) any of various proteins, as pepsin, originating from living cells and capable of producing certain chemical changes in organic substances;   b) a substance that has amino acids, compounds and carbon, hydrogen, oxygen, nitrogen and sometimes sulfur and is found in many foods (such as meat, milk, eggs, and beans) that is an important part of the human diet;   c) any of various soft, solid, or semisolid organic compounds forming the esters of glycerol and fatty acids and their associated organic groups;   d) the process by which food is converted into substances that can be absorbed and assimilated by the body;   e) the process in the human or animal body that makes something pass from the mouth, to the pharynx, and into the esophagus, while shutting the epiglottis.   f) the mechanical obstruction of the flow of air from the environment into the lungs. It prevents breathing, and can be partial or complete;   g) a carbohydrate consisting of a large number of glucose units joined by glycosidic bonds.   h) the process by which food is crushed and ground by teeth.

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