EXERCISE 6. Задайте по 10 вопросов по тексту”Digestion”.

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EXERCISE 6. Задайте по 10 вопросов по тексту”Digestion”.

EXERCISE 7. Перескажите текст ”Digestion”.

ACTIVE VOCABULARY

Read and learn the following words and word combinations:

1. harmless безвредный

2. dangerous опасный

3. subdivide подразделять

4. shape очертание, форма

5. decayed teeth гнилые (испорченные) зубы

6. chain цепь

7. cluster гроздь

8. strain штамм

9. gumboil флюс

10. acute острый

11.. gingivitis воспаление десен

12. exist существовать

13. survive выживать

14. resistant резистентный, устойчивый

MICROBIOLOGY.

The body provides a home for a great number of the smallest organisms – microorganisms. Most of them are harmless but some take part in dental diseases. There are three different groups of microorganisms: fungi, bacteria and viruses. They may be of different kinds, both harmless and more or less dangerous.

Bacteria are subdivided into groups according to their shape bacilli, cocci, spirochetes, spores.

Bacilli are rod – shaped bacteria. For example, lactobacillus is found in decayed teeth.

Cocci are round bacteria.

Streptococci are berry – shaped bacteria which grow in twisted chains. They are associated with different

diseases. Hemolytic streptococci (called hemolytic because bacteria cause hemolysis) are responsible for such conditions as “strep” throat, tonsillitis.

Streptococci viridians (viridians means “green” and these bacteria produce a green color on the growth medium) are less virulent (poisonous) than the hemolytic form and cause infections in teeth.

Staphylococci are bacteria which grow in small clusters like grapes. One strain of staphylococcus may be found in gumboils.

There are also spiral bacteria (spirochetes) found in acute necrotizing ulcerative gingivitis.

Some bacteria can exist in the form of spores. Spores can survive extremes of temperature and live for years until conditions become more favorable again. They are highly resistant to destruction.

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