THE RESPIRATORY

The system of specialized organs in taking oxygen from the respiratory form. Through the respiratory function is also eliminated as carbon dioxide, waste molecule of the breathing process cell. The air containing oxygen, enters the body through the nostrils, the openings that allow access to the nasal cavity. The tissue that lines the walls of these ducts is covered with cilia and produces mucus, with the function of retaining and push outwards impurities of different nature; is rich in blood capillaries that heat the incoming air. Are also presented for different olfactory cells that are sensitive to odors, can detect the presence of any harmful substances in the air breathed. Once through the mail in the pharynx retrobocca, the air continues its path in a series of tubes made of cartilage tissue, the first of which is the larynx. In this section there are the vocal cords, folds of mucous membrane that carpets the inner wall of the organ, they are the first and major organs of speech, it vibrates to the air flow emitted from the lungs, producing sounds.In the trachea, the air is to find in a tube consisting of superposed rings of cartilage, interrupted at the rear to allow the dilation of the esophagus during the descent of the food bolus. The inner epithelium that covers the larynx and trachea is still covered with cilia that keep the cleaning action.To the lower base of the trachea branch off two tubes, the bronchi, which convey the air towards the two lungs. In turn, the bronchi are divided several times in small tubes with a diameter of more and more reduced, bronchioles, which branch out inside the lungs forming a structure called the bronchial tree. Finally, the air reaches the lungs, two organs located entirely to the rib cage. They are constituted by a large number of bags of tiny size, densely surrounded by blood capillaries, called pulmonary alveoli. They are the functional units of the lungs and are gathered in hundreds and thousands to form clusters, called pulmonary acini, which come from the bronchioles, the air coming from the upper respiratory tract. Under the lungs is the diaphragm, a flat muscle with a curvature toward the top. When it contracts, reduces its curvature by increasing the volume available to the lungs; a result of which decreases the internal pressure that draws air from the outside: is the moment of inspiration. When you release, is arched upwards and compresses the lungs, increasing the internal pressure with the consequent expulsion of the air contained: is the moment of exhalation. Even the rib cage contributes to lung volume changes, in fact, the ribs are attached prior to the sternum with cartilage elasticity allowing some expansion of the otherwise rigid bone structure.