of small lobules connected together by connective tissue, different vessels and nerves.

b) This organ is pyriform in shape. It is a dilated portion of the alimentary canal. It is in the upper part of the abdomen under the diaphragm. The liver is above this organ, and the colon is below it. The pancreas is behind this organ.

3 Translate the following without consulting the dictionary:

1 Digestive juices are secreted into the alimentary canal by various glands and accessory organs. 2 The digestive system includes the organs that promote digestion and absorb the products of this process. 3 The alimentary canal includes the mouth, pharynx, esophagus, stomach, small intestine and large intestine. 4 The accessory organs include the salivary glands, liver, gallbladder and pancreas.

Unit 10

Pre-text assignments

1 Learn the key words and phrases:

innervation, distinct layers, innermost tissues, mucous membrane, folds, lumen, tubular invaginations, visceral peritoneum

2 Memorize the explanation to the terms:

The alimentary canal is a muscular tube about 9 meters long that passes through the body's ventral cavity. Although it is specialized in various regions to carry on particular functions, the structure of its wall, the method by which it moves food, and its type of innervation are similar throughout its length.

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The wall of the alimentary canal consists of four distinct layers, although the degree to which they are developed varies from region to region. Beginning with the innermost tissues, these layers, include the following:

1 Mucous membrane (mucosa). This layer is formed of surface epithelium, underlying connective tissue (lamina propria), and a small amount of smooth muscle. In some regions, it develops folds and tiny projections that extend into the lumen of the digestive tube and increase its absorptive surface area. It may also contain glands that are tubular invaginations into which the lining cells secrete mucus and digestive enzymes. The mucosa protects the tissues beneath it and carries on absorption and secretion.

2 Submucosa. The submucosa contains considerable loose connective tissue as well as blood vessels, lymphatic vessels, and nerves. Its vessels nourish the surrounding tissues and carry away absorbed materials.

3 Muscular layer. This layer, which is responsible for the movements of the tube, consists of two coats of smooth muscle tissue. The fibers of the inner coat are arranged so that they encircle the tube, and when these circular fibers contract, the diameter of the tube is decreased. The fibers of the outer muscular coat run lengthwise, and when these longitudinal fibers contract, the tube is shortened.

4 Serous layer (serosa). The serous, or outer covering of the tube is composed of the visceral peritoneum, which is formed of epithelium on the outside and connective tissue beneath. 6 The cells of the serosa secrete serous fluid, which keeps the tube's outer surface moist. This lubricates the surface so that the organs within the abdominal cavity slide freely against one another.

Post-text assignments

1 Answer the following:

1 What is the alimentary canal?

2 Distingwish between mucosa and submucosa.

3 Distingwish between muscular layer and serous layer.

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2 Ask questions using the parenthesized words:

1 The alimentary canal is a muscular tube about 9 maters long. (What size) 2 The wall of the alimentary canal consists of four disfinct layers. (How many) 3 Mucous membrane is formed of surface epithelium and a small amount of smooth muscle. (What ...

of) 4 The mucosa protects the tissues beneath. (What) 5 The fibers of the outer muscular coat run lengthwise. (How) 6 The cells of the serosa secrete serous fluid. (What)

3 Summarize the characteristics of these layers:

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