Unit 12

Pre-text assignments

1 Learn the key words and phrases:

deaminating amino acids, blood clotting, bile, fibrous capsule, hepatic cells, gallstones

2 Use the following words and expressions in sentences of your own to show that you understand their meaning and use:

use by expiration date; if pain persists; the advice of a health professional; to depend on; reduced doses are recommended; rectal route of administration; oral route of administration; intravenous route of administration; subcutaneous route of administration; drug introduction into

Liver

The liver is located in the upper right and central portions of the abdominal cavity, just below the diaphragm. It is partially surrounded by the ribs, and extends from the level of the fifth intercostal space to the lower margin of the ribs. It is reddish brown in color and well supplied with blood vessels.

The liver is the largest gland in the body, and it carries on many important metabolic activities. For example, it plays a key role in carbohydrate metabolism by helping maintain the normal concentration of blood glucose.

The most vital liver functions are probably those ­related to protein metabolism. They include deaminating amino acids; forming urea; synthesizing various blood proteins, including several that are necessary for blood clotting ; and converting various amino acids to other amino acids.

The liver also stores a variety of substances, including glycogen, iron, and vitamins A, D, and B₁₂. Iron storage occurs when the concentration of blood iron is excessive. The extra iron is combined with a protein (apoferritin) in liver cells, and as a result, a substance called ferritin is formed. The iron remains stored in this form until the blood iron concentration reaches a certain low level. Then some of the iron is released. Thus, the liver plays an important role in the homeostasis of iron.

In addition to the above functions, various liver cells help destroy damaged red blood cells and foreign substances by phagocytosis, alter the composition of toxic substances such as alcohol (detoxification), and secrete bile. The liver can also store from 200 to 400 milliliters of blood, thus it serves as a blood reservoir.

The liver is enclosed in a fibrous capsule and is divided by connective tissue into lobes—a large, right lobe and, a smaller, left lobe. Within the liver lobules, are many fine bile canals, wich receive secretions from the hepatic cells. Bile is a yellowish green liquid that is secreted continuously by the hepatic cells. It is the only liver secretion that directly affects digestion. Bile contains bile salts, bile pigments, cholesterol, and various electrolytes. Only the bile salts have digestive functions. The gallbladder stores bile between meals. Release of bile from the common bile duct is controlled by a sphincter muscle. Gallstones may sometimes form within the gallbladder.

Post-text assignments

1 Choose the proper terms for the definitions:

1 Yellow coloration of skin and tissues. 2 Lack of hydrochloric acid. 3 Lesion of the mucous membrane when it is injured and necrosed. 4 Collection of bile (calculi) which forms in the gallbladder and bile ducts. 5 Protrusion of an organ or part of it through the wall of the cavity which contains it. 6 Binding or twisting of the intestine upon itself. 7 Removal of the gallbladder. 8 Inflammation of the pancreas. 9 Incision of the esophagus. 10 Visual examination of the stomach.

(a – gallstones; b – hernia; c – volvulus; d – gastroscopy; e – ulcer; f – achlorhydria; g – pancreatitis; h – cholecystectomy; i – esophagotomy; j – jaundice)

2 Translate in writing:

Gallstones may form if the bile is concentrated excessively, if the hepatic cells secrete too much cholesterol, or if the qallbladder is inflamed (cholecystitis). If such stones get into the bile duct, they may block the flow of bile, causing obstructive jaundice and considerable pain. Generally gallstones that cause obstructions are surgically removed. At the same time, the gallbladder is removed by a surgical procedure called cholecystectomy. Following such surgery, the person is unable to produce gallstones or store bile. However, bile continues to reach the intestine by means of the hepatic and common bile ducts.