Text B. Conditioned Reflexes

All the visceral and somatic reflexes including the protective, feeding and others are formed by various internal and external stimuli. These stimuli produce reactions not depending on surrounding conditions. The great Russian physiologist Pavlov called them nnconditioned reflexes.

In human beings the nervous system has the additional ability to form cortical associations which increase the range of reactions. This function is obtained by all the human beings and formed upon signalization, i.e. the process in which an ineffective reflex stimulus forms the same reactions as the stimulus with which it has become associated. Pavlov called these individually obtained reflexes conditioned, because they are developed only in connection with some other reflexes.

It is through constant contacts of life that men develop many conditioned reflexes. They begin to develop already in infancy. During human development their number is much increased through training and education.

In experimental conditions it was determined by Pavlov that many new conditioned reflexes to stimuli not supplied by Nature could be established in dogs. But such stimuli had to be associated with those which formed an unconditioned response. Pavlov determined that in higher animals it was in the cortex that conditioned reflexes were formed.

LESSON 22

HOME ASSIGNMENTS

I. Запомните факты, изложенные ниже:

Do you know that

1. the vision centres are located in the occipital [ok'sipitl] area of the cortex? 2. the nervous system of the human being has about ten times more nervous cells than the number of all people in the world? 3. the stimuli pass into the brain through the spinal cord very rapidly — about 100 m per second?

II. * Закончите предложения, выбрав необходимые по смыслу слова:

1. The ear is the sense organ of (vision, hearing). 2. The human being smells with (the nose, the eye). 3. The motor cortex controlling many body movements (becomes tired rapidly, is almost never tired). 4. The stimuli from different parts of the human body come to the brain through (the blood vessels, the nerve fibers in the spinal cord).

III. На основании следующих формул напишите и назовите инфинитивы (см. таблицу 22, стр. 292)

1. от глагола to determine:

 

2.* От глаголов to add, to bring, to connect

IV. * Найдите и назовите инфинитивы:

1. Не may examine the patient. 2. He may be examining the patient now. 3. He may have examined the patient already. 4. He may be examined by Doctor Sedov. 5. He may have been examined by 11 a.m.

V. Прочтите следующие предложения, обратите внимание на перевод модальных глаголов и инфинитивов, стоящих после них. Ответьте на вопросы: