Gas exchange

Oxygen, which enters in the cloth, is used for oxidizing the products, which are formed as a result of the long chain of chi -mic. of the transformations of carbohydrates, it is fatty and proteins. In this case they are formed WITH₂, water, nitrous connections the let-loose energy, utilized for maintaining the temperature of body and fulfillment of work. A quantity of resultant in the organism and in the final analysis of that separating from it with₂ depends not only on a quantity of that consumed about₂, but also on the fact that preim. is oxidized: carbohydrates, fats or squirrel. The ratio of that moved away from the organism WITH₂ to that absorbed in the same time against₂ NAZ by the respiratory coefficient, which is equal to approximately 0,7 with the oxidation it is fatty, 0,8 with the oxidation of proteins and 1,0 with the oxidation of carbohydrates. The quantity of energy, which is freed on 1 l of that consumed about₂ (calorific equivalent oxygen A), equal to 20,9 kJ (5 kcal) with the oxidation of carbohydrates and 19,7 kJ (4,7 kcal) with the oxidation it is fatty. Thus, on the consumption about₂ per unit time and on the respiratory coefficient it is possible to calculate a quantity of energy freed in the organism.

G. (respectively and energy consumption) in cold-blooded animals (cold-blooded) it is reduced with a decrease in the temperature of body. The same dependence is discovered in homoiothermal animals (warm-blooded animals) with the disconnection of thermostatic control (under the conditions of natures or skills, hypothermia); with an increase in the temperature of body (with the overheating, different diseases) g. it increases.

With a decrease in the ambient temperature g. in warm-blooded animals (especially in small) it increases as a result of an increase in the heat production. G. increases also after the intake of the food, especially rich in proteins (Vol. n. the specific- dynamic action of food). Maximum values G, it reaches with the muscular activity. In man with the work of the moderate power g. it increases, 3-6 min after its beginning it reaches the specific level and then it is retained in entire period of work at this level. With the work of large power g. continuously it grows; soon after the achievement of the level (maximum aerobic work) of slaves against thatmaximum forthisperson it is necessary to cease, since the need of organism v about₂ exceeds this level. At first after the end of work remains the increased consumption about₂, the utilized for the coating oxygen debt, i.e. for oxidizing the products of exchange of substances, which were being formed during the work. Consumption about₂ can increase from 200-300 ml/min in the state of rest to 2000-3000 with the work, and in the well trained athletes - to 5000 ml/min. Isolation WITH ₂ andenergy consumption respectively increase; simultaneously occur the shifts of respiratory coefficient, connected with changes in the exchange of substances, acid-base equilibria and pulmonary ventilations.

The calculation of general daily energy consumption in people of different professions and means of life, based on the determinations of g., is important for rate setting of nourishment. Studies of changes g. with the standard phys. to work adapt in the physiology of labor and sport, in the clinic for evaluating the functional state of the systems, which participate in G.

It will compare, constancy g. with means, changes of the partial pressure about₂ in environment, disruptions of the work of the organs of respiration and the like it is ensured by the adaptive (compensatory) reactions of the systems, which participate in g. and adjusted by nervous system.

G. in man and animals is accepted to investigate under the conditions of complete rest, on an empty stomach, at a comfortable temperature of medium (18-22 °S). Quantities of that consumed in this case about₂ and let-loose energy characterize basal metabolism. For the study g. adapt the methods, based on the principle of the open or closed system. In the first case a quantity of exhaled air and its classification (with the aid of the chem. or the phys. of gas analyzers), are defined that it makes it possible to calculate quantities of that consumed about₂ and isolated WITH₂. In the second case

Schematic of apparatus for investigating the gas exchange: U - device for the power feed of oxygen: B - vessel with oxygen; K - camera; X - refrigerator; 5 - vessel with the alkali for the catching of carbon dioxide; N - pump; SaS.l₂- vessel with chloride calcium for absorbing the water is steam: T - thermometer; M - manometer.

respiration occurs in the closed system (germetich. to camera or from the spirograph, connected with the respiratory tract), in which that isolated WITH ₂is absorbed, and a quantity of that consumed from the system about₂ is determined either by the measurement of an equal to it quantity of that of automatically entering the system about₂or on the decrease of the volume of system (Fig.).

Lit.: Ginetsknekiy A. g., Lebedinskiy A. V., the course of normal physiology, M., 1956; Physiology of man, M., 1966, s. 134-56; Berkovich e. M., energy exchange in the standard and the pathology, M., 1964 (there is bibl.); Prosser L., Brown f., the comparative physiology of animals, translated from English, M., 1967, s. 186-237. L. l. shik.