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 physiologist Pavlov called them unconditioned reflexes.

In human being 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.

Home Assignments 2

Task 1 Memorize the facts given below:

Do you know that:

Тhe vision centres are located in the occipital areas of the cortex.

Тhe nervous system of the human being has about ten times more nervous cells than the number of all people in the world.

Тhe stimuli pass into the brain through the spinal cord very rapidly – about 100 m per second.

Task 2 Choose the proper ending to complete the sentence:

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).

Task 3 Find the infinitives:

1 He may examine the patient.

2 He may be examining the patient.

3 He may have examined the patient already.

4 He may be examined by Doctor Kovalenko.

5 He may have been examined by 11 a.m.

Task 4 Read the sentences, pay attention to the translation of the modals and infinitives following them:

1 He cannot do it. – Він не в змозі цього зробити.

He cannot have done it. – Не може бути, щоб він це зробив.

Can he have done it? – Невже він це зробив?

2 He may perform an operation on the heart. – Можливо,він робить операцію на серці.

He may have performed an operation on the heart. – Можливо, він зробив операцію на серці.

You must deliver a lecture. – Ви повинні читати лекцію.

You must have delivered a lecture. – Напевно ви прочитали лекцію.

Task 5 Translate the following sentences:

1 Can the patient have developed such a bad pain in the stomach after taking the medicine?

2 The infant is quiet now. Mother must have fed it.

3 The blood pressure may have decreased after the administration of this drug.

4 Can the investigator have drawn such a conclusion after a number of experiments?

Task 6 Learn the following words and word combinations:

delicate – слабкий, хрумкий

inhibit– уповільнювати

allow– дозволяти

provide with – забезпечувати

provide for – передбачати

provided– за умов, що

smooth– гладенький, рівний

purpose– мета

fall– падати, знижуватися

fall asleep– засинати

fall ill with – захворіти

significance – значення, важливість

quiet– спокійний, тихий

drop– ронити, капати

though– хоча

spread– поширювати(ся)

Task 7 Translate the words with the same root:

act, action, activity, react, reaction, reactive; significance, significant, insignificance, insignificant, insignificantly; to tire, tired, tiredness; inhibit, inhibition, inhibitory, inhibitor; quiet, quietly, quietness.

Task 8 Learn the following word combinations paying attention to the prepositions:

to provide with, to provide for, to fall ill with, to drop into, for some purpose, to be of some significance, to react to smth, to spread over / to smth.

Task 9 Translate the following word combinations:

– слабке здоров’я, крихкі клітини, делікатна операція, гладенькі м’язи, рівна бічна поверхня, тихий відпочинок, спокійний сон, міцне здоров’я, глибокий сон;

– падати, я впав, хворий заснув, я впустив термометр, закапати ліки в очі, він захворів на пневмонію, дозволити хворому пересуватися, хворому дозволили сісти, лікар не дозволяє мені втомлюватися, забезпечити, наша бібліотека забезпечує нас книгами, це було передбачено заздалегідь, ми виконали багато дослідів задля цієї мети, сон має велике значення для життєдіяльності людини, біль поширилася по руці.

Task 10 Translate the words given in parentheses and then translate the sentences:

1 When the man feels (втомленим) he (засинає).

2 The external surface of the liver is (гладенька).

3 Sleep is of a great protective (значення) to the human being.

4 Please be (тихо), the patient has just fallen asleep.

5 When the doctor was examining the patient he determined that the heartbeat was (уповільнений).

Task 11 Read the text. Entitle it. Find the sentences with the word “one” used as a subject. Translate these sentences. Write down the equivalents of the following word combinations:

1) задля цієї мети; 2) цілковитий спокій; 3) поширюється по корі головного мозку; 4) має велике значення для; 5) глибокий спокійний сон; 6) життєдіяльність.

The nervous cells of the cortex are the most delicate of all the cells of the human body.

It is at the moment of tiredness of the cortical nervous cells that the process of inhibition begins to act. The process does not allow new stimuli to pass to the tired areas of the brain. To provide the smooth work of the brain the nervous cells must be well supplied with oxygen and feeding substances. And for this purpose any human being must have regular complete rest, i.e. sleep.

When the process of inhibition extends over a great number of cells, spreads widely over the cortex and even over the subcortical areas of the brain one falls asleep.

When one sleeps the vital activity of the nervous system is restored. So sleep is of a great protective significance to the human being.

The man sleeps about one third of his life. Numerous investigations and experiments have shown that sleep is more necessary for the human being than food. One can live longer without food than without sleep.

During a sound quiet sleep the whole activity of the human organism changes, the body metabolism decreases, the respiratory and pulse rates become slower, the body temperature drops. Though the stimuli continue to come into the brain, the inhibited cortical cells do not react to them.