Breathing System

The basic structures of the breathing system are the nose, pharynx, larynx, trachea, bronchi and lungs.

A very important factor in aerobics is breathing. The oxygen divides the breathing in two types:

Aerobic breathing, when it is realised in the presence of oxygen.

Anaerobic breathing,when it is realised in the absence of oxygen. This type of breathing unwinds into the tissues, at metabolic level.

The aerobic breathing is realised externally (lungs), or internally (tissues and cells). The oxygen's absorption from outside provokes diffrent biochemical oxidative reactions.

The respiratory system is formed of epithelial tissues and elastic fibres, that form a tissue of little bulls- alveoli- and its walls are serve like endings for the capillaries of the pulmonary artery. This goes through a forest of bronchias, the trachea, the rinopharynx, and their alveoli communicate with the outside. The exchange of gases between blood and air doesn't realize like in the alveoli, but it remains, somehow, tight like a communication way.

As we know, the lung capacity is changeable. This variation of capacity is made in the rational time from the difference between the atmospheric pressure in the lungs and the outside pressure.

During inhalation, the capacity of the lungs increases; during of exhalation the phenomenon is opposite: due to the pressure of the thoracic box and the intercostal muscles's compressure, the air goes out where the pressure is lower.

In the muscular rest, man effectuates 14-18 breathings per minute, and the quantity of changed air is 0.4-0.6 litres /breathing motion.

When we are making intens physical excercises, we make from 25 to 40 inspirations per minute, and the amount of changed air in each moment inereases to 2.5-3 litres, reaching 90-120 litres per minute.

The atmospheric air contains the next gases:

• oxygen: 20.93%-20.94%
• carbon dioxide: 0.03%-0.04%
• inert gases: argon, Kripton, helium, neon:1%

The air exhalled coutains 15.5%- 18%oxygen and 2,5 -5% carbon.

The vital capacity of the lungs

During by a normal respiration (inhale- exhale )man has 500 centimetre cubes of air pulled upon the lungs. This air is called "tidal air".

By a maximum inhalation effort, one can draw in the lungs about 1500-1800 centimetre cubes of air , this amount being known as "complemental air".

The air exhaled in a maximum and forced exhalation is called "air of reserve", and represents 1000-1500 cm cubics, sometimes more than that(2-2,5 litres ).

The "vital capacity " is represented by the amount of air replaced between a strongest possible inhalation and a maximal exhalation.

For women this amount is of 3.0 -3.6 litres, but for men this amount is of 3.5 - 4 litres.

To trained people and sportsmen the "vital capacity" is above 5 litres. We can calculate the amount of the "vital capacity " ( in centimetre cubes ) if we have information about one 's height (in centimetres ); we multiply it by 20 for women and by 25 for men.

More the capillaries refill with blood, lower it gets the value of the "vital capacity ", because the volume the alveoli decreases in this case! This fact is due to the strong physical efforts or to disorders of breathing.

The oxygen need. The oxygen dest. Signal of excitation in aerobics.

A complex biochemical process of anaerobic transformation takes place in the muscles. This represents a souce of energy production. The substances created in this process are the molecules originated in the desintegretion of mycromolecullar combinations (the lactic acid, for example ).

The oxygen once arrived at the muscles, via blood vessels, oxidizes these substances releasing a big amount of energy. For a minute of work or physical exercises, the necessary amount of oxygen for oxidizing all the disintegrated substances in a anaerobic way is called "oxygen request".

Conclusion: when the spent amount of oxygen in a minute is equal to the "oxygen request ", the concentration of unoxidized substances in the blood doesn't increase. It is sufficient the installation of a permanent corelation between the amount of oxygen and the request of oxygen during all the working periods, because this correlation lasts for a long time. When we get at this fitness level, we can say that the person is "in good shape".

Therefore, the oxygen supply depends on the pulmonar respiration and the blood flow.