11. Анатомия и физиология опорно-двигательной системы



 

-          Hi, how are you doing?

-          Very good, thank you.

-          Did you go to the lecture on the skeleton and muscles yesterday? You know I was surprised to know that there are more then 200 bones in the adult skeleton.

-          Yes, and 26 of them are only bones of the skull, which consists of cranial and facial parts. The bones of the trunk are the spine and the chest. The spine consists of the 7 cervical, 12 thoracic, 5 lumbar and 5 sacral vertebrae and … and…

-          And a coccyx. I know that. By the way, what are the largest vertebrae in the spine?

-          Let me think… the lumbar vertebrae are the largest ones. Do you know that the chest (thorax) consists of 12 thoracic vertebrae, the breastbone and 12 pairs of ribs? And the breastbone is composed of 3 main parts.

-          I know. I know that the basic part of the chest is formed by ribs. On each side of the chest 7 ribs are connected with the breastbone by cartilages. The cartilages of 3 other ribs are connected with each other and with the 7 ribs but are not connected with the breastbone. But I don’t remember anything about the 11^th and the 12^th ribs.

-          Oh, they are not connected with the breastbone either, they are not even connected with other ribs. They are free. I wonder if you know how many parts the lower and the upper extremities consist of.

-          Certainly. The lower extremity consists of the thigh, leg and a foot and the upper extremity is formed by the arm, forearm and hand. Our body is also composed of about 600 skeletal muscles and they all are divided into the muscles of trunk, head and extremities.

-          Yes, and according to their form they may be divided into long, short and wide muscles. Long muscles form the free extremities, wide muscles lay on the trunk and the walls of the body cavities are formed by short muscles. Am I right saying that skeletal muscles are formed by a mass of muscle cells?

-          Yes, you’re. The muscular fibers are connected together by connective tissue and there are blood vessels and the nerves in the muscles.

-          Certainly. I think we’ve mentioned everything. I must go now.

-          Oh, sure. Thank you.

12. Анатомия и физиология дыхательной системы



 

-          Hello. What are you doing? Are you free now?

-          Yes, I’m.

-          Then let’s prepare our Anatomy lesson on the lungs for tomorrow.

-          Ok. So… the lungs are the main organs of the respiratory system and there are 2 of them in the human body.

-          Right! They are separated from each other by the Mediastinum and covered with the pleura. By the way, each lung has the base, apex, two borders and three surfaces. Do you know what the weight of the lungs and their vital capacity is?

-          Well… their weight varies according to many conditions. It’s about 1350 gr in the adult male. Their vital capacity is about 3-4 liters.

-          Yes. That’s right. Moreover, the right lung consisting of 3 lobes is heavier than the left one, because the latter consists only of 2 lobes. What does the structure of the lung consist of?

-          Let me think … it consists of an external serous coat, the visceral layer of the pleura, a Subserous elastic tissue and the parenchyma or proper substance of the lungs. Do you know that the physiology of the lungs is associated with their structure?

-          Yes, I do. There are over 700 000 000 alveoli in the lungs. The lungs have also many capillaries. This particular structure of the lungs enables the exchange of gases between the alveolar air and the blood.

-          But not all the alveoli and capillaries of the lungs are opened when one breathes normally. But their number increases, when respiration becomes deep. Moreover, when the depth of respiration increases the vital capacity may be 6 liters and even more.

-          Sure, the regulation of the vital capacity of the lungs is of particular importance to the exchange of oxygen and carbon dioxide taking place in the lungs. Do you know that the lungs take part in the production of physiologically active substances?

-          I do. They also take part in the regulation of blood coagulation, in the metabolism of protein, fats and carbohydrates.

-          Right you are. I think that’ll do. I’m sure tomorrow we will answer.