Theme №9. P. Pavlov
The purpose of the lesson:
1. To ensuring fundamental education in the natural-science subjects.
2. To broaden student's outlook and acquaint with professional terms.
3. To encourage the interests of learning foreign language.
P. PAVLOV
If you visit the Pavlov Biological Station at Pavlovo near Leningrad, you will see a very interesting monument there. It is a monument to the dog. The dog as you know played a very important part in all Pavlov's experiments on the activity of the higher nervous system. In the name of science and humanity, Pavlov wanted to thank the dog; so this monument was put up.
Then if you go to see Pavlov's study the room in which the great scientist worked for so many years, you will notice another dog, a toy one, standing on the bookcase. This toy dog has a very interesting history. It comes from Cambridge, England, where there is one of the oldest Universities in the world.
On the 18th of July 1912, a group of students stopped before the window of a toyshop in Cambridge and looked at the toy dogs there. "There is the thing we want", said one of them, and he pointed to a big white dog in the shop window. They entered the shop and asked for this toy to be packed. Soon they came out with a parcel containing the big white dog. Then, laughing and talking, they hurried to the laboratory of their physiology professor and showed the dog to him.
The professor did not understand what it was all about until Archibald Hill, now one of the greatest physiologists in the world told him about their plan. It was this. They knew that the next day some foreign scientists were to come to Cambridge. Among these was Ivan Petrovich Pavlov, the great Russian experimenter and physiologist. So the students wanted to present Pavlov with a toy dog. "Where did you get the idea from" — asked the professor. "I think it's an excellent one". "I got it from the grandson of Charles Darwin, who is now a student here", answered Hill. "When Darwin got his doctor's degree at Cambridge, the students of that time gave him a toy monkey. That was how they showed that they supported his theory of the origin of man. Now we shall honour Pavlov in the same way?”
The next day was a great holiday of Cambridge. Thousands of people came to see the foreign scientists receive their diplomas. The students watched the ceremony from the gallery. When the Speaker had made his speech, which was in Latin, the chancellor gave the doctors their diplomas one by one and they sat down at the great table on the platform.
Now it was Pavlov's turn. As he was moving slowly forward under the gallery, the students let the dog fall right down into his arms. He looked up, saw all the young, smiling faces above him and immediately understood what they meant. The students knew him too. It was one of the happiest moments in his life. As this was taking place, aft old professor on the other side of the hall said to his neighbour: "Look, the students are giving Pavlov a toy dog. Did you see Darwin get his diploma? Do you remember him standing there with a toy monkey in his arms nearly forty years ago? History repeats itself, doesn't it?" Ivan Petrovich Pavlov set out to find out how the food made the stomach juice flow. Did it work through chemicals, or nerves, or what? Was this flow of juices influenced by what a person ate, how the food looked and tasted, by the person's thoughts? Doctors, Pavlov realized, had to know the answers to these questions if they were going to make people healthier or even save their lives. Here is what Pavlov did: he anesthetized a dog — that is, he gave it some medicine that would keep it from feeling any pain.
He made an opening in the outside wall of the dog's abdomen. Then he took a part of the dog's stomach and made a pouch of it. This pouch had all the nerves and blood vessels that the rest of the stomach had- Pavlov made a separate opening in the pouch that led out through the hole in the abdominal wall. Then Pavlov fed the dog. As soon as food got into its mouth, juice began to pour into the stomach. Some juice also poured into the pouch, and the scientist collected it in a little bottle through the opening in the abdominal wall. This experiment was one more proof that food itself starts its own digestion going. Pavlov showed that the presence of food in the mouth started nerve impulses that went to the brain and then to the cells of the stomach, then secreted or poured out juices. When he cut the vagus nerves, which bring impulses from the brain to the stomach, the dog's mouth could be stuffed with food yet no juices would be secreted in the stomach.
Just as you don't have to think in order to breathe, you don't have to think to digest. You can drink a glass of hot milk before you go to bed, and it will be digested long before morning. It is digested while you are asleep. We call such an activity of the body, which involves nerves and happens automatically, a reflex. When food enters the mouth, a nerve impulse goes to the medulla. This is then "reflected" back by the nerves to the stomach. When the impulse reaches the stomach, the muscles contract and the cells secrete their juices. Physically and chemically, digestion has started. Pavlov also showed that the sight, the smell, even the thought of food could start the reflexes going and the stomach secreting. At the thought of a nice thick steak, you could really say: "My stomach waters". This kind of reflex Pavlov called a conditional reflex.
Divide the text into logical parts.
