Wednesday, June 20, 2018

Oxygen And How We Breathe

Oxygen is a slightly magnetic gaseous element, colorless, odorless and tasteless. Oxygen is the most abundant element on Earth. It was discovered in 1774 by British chemist Joseph Priestley and independently by the Swedish chemist Carl Wilhelm Scheele, the French chemist Antoine Laurent Lavoisier showed that it was an elemental gas by his classic experiments on combustion.

How We Breathe

Vertebrates, and that includes us, breathe into the lungs which are inside our chest. An important part of our breathing process is the rib cage, and in its base is the diaphragm. The ribs move down and to the front as they expand and contact by means of the intercostal muscle. The result of this is greater volume of air in the chest cavity.

The volume of the thorax is also increased by the downward contraction of the muscles of the diaphragm. Inside the chest, the lungs are kept near the chest wall without collapsing due to pressure in its interior. When the chest expands, the lungs begin to fill with air during inspiration. The relaxation of the strained chest muscles allows them to return to their natural state collapsed, forcing the air out of the lungs.

With each breath more than 500 cc of air is inhaled and exhaled, this is called the volume of air flow or lung ventilation. You can still breathe more air up to cc 3,300 through forced inspiration, which is the amount known as inspiratory reserve volume. Once this amount of air is exhaled, you can still breathe 1,000 cc, with a forced expiration, and this is known as the expiratory reserve volume. The sum of these three quantities is called vital capacity. In addition, the lungs are always 1,200 cc of air which can not escape and is called residual air volume or alveolar.

The human lung is reddish and pyramid-shaped, consistent with the shape of the chest cavity. They are not completely symmetrical as the right lung is divided into three lobes and the left two, as here is a cavity which houses the heart. In the middle of each one of them is the root of the lung, which connects to the mediastinum or the lung portion of the chest. The root is made up of two layers of the pleura, bronchi, veins and pulmonary arteries. Bronchi of the lungs are divided and subdivided until the end of the lobule, the anatomical and functional unit of the lungs.

The pulmonary arteries and veins accompany the bronchi in progressive branching to become fine arterioles and venules of the lobules, and these in turn into a network of capillaries that form the walls of the pulmonary alveoli. Pulmonary plexus nerves and lymphatic vessels are also distributed in the same way. In the lobule, the bronchioles are separated to form the terminal bronchioles, which are open to the atrium or alveolar duct. Each atrium is subdivided into alveolar sacs, and these into alveoli.

The main nerve centers that control the pace and intensity of respiration are in the medulla oblongata (or medulla oblongata) and pons (or pons) of the brain stem (see Brain). The cells of this nucleus are sensitive to the acidity of the blood and depend on the concentration of carbon dioxide in the blood plasma. When the acidity of the blood is high the respiratory center stimulates the respiratory muscles to increase their activity. When the concentration of carbon dioxide is low, respiration slows down.

A circulatory failure may cause anoxia in the tissues of the body where the circulatory volume is inadequate or when the oxygen-carrying capacity is impaired. Other disturbances of the respiratory system are for example, bronchial asthma, rapid decompression syndrome, Bronchitis, Common cold, diphtheria, influenza, pleurisy, pneumonia, tuberculosis.



Source by Philip Robinson

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