Digestive system and digestion

The human body needs energy for its functioning. Our body assimilates proteins, fats, carbohydrates and other nut­rients. The digestion of the starchy parts of food begins in the mouth where it is moistered with saliva. In the tongue papillae (lingual papillae) there are the taste receptors. Over the mucous membrane of the oral cavity there are many tactile, temperature and pain receptors. The teeth, the gums, the soft and hard palates and the salivary glands are important structures located in the oral cavity. In the oral cavity the food must be well chewed between the teeth. Then the food passes through the pharynx (throat) and down through the esophagus (gullet) into the stomach which is a dilated portion of the alimentary truct pyriform in shape. The stomach is composed of a fundus (upper part), a body (middle part) and an antrum (lower, distal part). The upper opening of the stomach is called the cardiac sphincter and the lower one — pyloric. The folds in the mucous membrane lining the stomach are called rugae.

In the stomach the components of food are dissolved and hydrolysed by enzymes of saliva and gastric juice. Different gastric glands are found in the stomach. They produce hyd­rochloric acid and pepsin to digest food. The gastric juice secreted by the stomach possesses antibacterial activity. Pepsin converts proteins to smaller substances called peptones. But food does not enter the bloodstream through the stomach.

Further digestion and absorbtion of food into the blood takes place in the small intestine. After portions of the stomach contents enter into the duodenum they turn acid, but then the reaction rapidly changes because the hydrochloric acid of the gastric juice is neutralized by the bile, the juice of the pancreas, the juice of the duodenal glands and intestinal crypts. The bile comes from the liver and gallbladder by means of special ducts. The pancreatic juice, a colourless clear fluid contains sodium, potassium chlorides and is rich in enzymes which digest proteins, fats and carbohydrates.

Food passes in peristaltic waves from the duodenum to the jejunum and the ileum, which is attached to the large intestine. The entire small intestine has many projections called villi. It is in the small intestine where the so-called cavital-and membrane hydrolyses of nutrients takes place. The products of digestion are absorbed into the blood and lymph.

The remaining part of food (the fluid by-products of diges­tion) from the small intestine pass into the large intestine which consists of cecum, colon (ascending, transverse, descending), sigmoid colon and rectum. The vermiform appendix hags from the cecum. The rectum ends in the anus. The process of diges­tion is completed in the large intestine by the absorption of water. The unabsorbed and undigested components of food, the remains of the digesting fluids are evacuated from the body.

Task 4. Read the dictionary article with examples from “The Longman Register of New Words” and say what it is about:

Graze

Graze — to eat continuously in small amounts throughout the day, rather than at set meal times.

Traditional meal times arc 'blurred' and consumers 'graze' — 'a nibble here and a nibble there, spread unpredictably across the day.’

The growth of 'grazing', says the report, has developed in the last 10 years, and its potential has not yet been recognised by the catering industry

We cat on the run, on average 6 times a day, grazing through packet after packet of crisps, nuts and savouries.

Task S. Read the article from “The Second Barnhart Dictionary" and explain the difference between dietary fiber and crude fiber:

Dietary Fiber

Dietary fiber is roughage in vegetable and fruits, eaten to promote health.

Dietary fiber was the latest dietary component to be hailed as the one that docs it all. Dietary fiber should not be confused with crude fiber; it includes structural polymers of cell walls, celluloses, hcmicclluloscs, pectin, lignin, and undigested polysaccharides, and may be three to seven times more plentiful in a diet than the crude fiber included in food com­position tables.

The researchers gave one group of rats a cholesterol-free, chemically defined liquid diet, another group of rats the same diet with cholesterol and still a third group of rats a standard formula diet (in order to serve as a control to the other two groups) By design all three diets were fiber- free, since dietary fiber may protect against colon cancer, and provided equivalent caloric intakes.

Task 6. Find the English equivalents for the Latin terms: