The Human Lungs Biography
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To understand the anatomy of the lungs, the passage of air through the nose and mouth to the alveoli must be studied. The progression of air through either the mouth or the nose, travels through the nasopharynx, oropharynx, larynx, and the trachea (windpipe). The air passes down the trachea, which divides into two main bronchi; these branch to the left and right lungs where they progressively subdivide into a system of bronchi and bronchioles until the alveoli are reached. These many alveoli are where the gas exchange of carbon dioxideand oxygen takes place.
Breathing is driven by muscular action; in early tetrapods, air was driven into the lungs by thepharyngeal muscles via buccal pumping, which is still found in amphibians. Reptiles, birdsand mammals use their musculoskeletal system to support and foster breathing. Medical terms related to the lung often begin with pulmo-, such as in the (adjectival form:pulmonary) or from the Latin pulmonarius ("of the lungs"), or with pneumo- (from Greekπνεύμων "lung"). The lung is the essential respiration organ in many air-breathing animals, including mosttetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart. Their principal function is to transport oxygen from the atmosphere into the bloodstream, and to release carbon dioxidefrom the bloodstream into the atmosphere. A large surface area is needed for this exchange of gases which is accomplished by the mosaic of specialized cells that form millions of tiny, exceptionally thin-walled air sacs called alveoli. The lungs of mammals including those of humans, have a soft, spongelike texture and are honeycombed with epithelium, having a much larger surface area in total than the outer surface area of the lung itself.
Breathing is largely driven by the muscular diaphragm at the bottom of the thorax. Contraction of the diaphragm pulls the bottom of the cavity in which the lung is enclosed downward, increasing volume and thus decreasing pressure, causing air to flow into the airways. Air enters through the oral and nasal cavities; it flows through the pharynx, then thelarynx and into the trachea, which branches out into the main bronchi and then subsequent divisions. During normal breathing, expiration is passive and no muscles are contracted (the diaphragm relaxes). The rib cage itself is also able to expand and contract to some degree through the use of the intercostal muscles, together with the action of other respiratory and accessory respiratory muscles. As a result, air is transported into or expelled out of the lungs. This type of lung is known as a bellows lung as it resembles a blacksmith's bellows.
In humans, the trachea divides into the two main bronchi that enter the roots of the lungs. The bronchi continue to divide within the lung, and after multiple divisions, give rise to bronchioles. The bronchial tree continues branching until it reaches the level of terminal bronchioles, which lead to alveolar sacs. Alveolar sacs, are made up of clusters of alveoli, like individual grapes within a bunch. The individual alveoli are tightly wrapped in blood vessels and it is here that gas exchange actually occurs. Deoxygenated blood from theheart is pumped through the pulmonary artery to the lungs, where oxygen diffuses into blood and is exchanged for carbon dioxide in thehaemoglobin of the erythrocytes. The oxygen-rich blood returns to the heart via the pulmonary veins to be pumped back into systemic circulation."Lung Disease & Respiratory Health Center".
Human lungs are located in two cavities on either side of the heart. Though similar in appearance, the two are not identical. Both are separated into lobes by fissures, with three lobes on the right and two on the left. The lobes are further divided into segments and then into lobules, hexagonal divisions of the lungs that are the smallest subdivision visible to the naked eye. The connective tissue that divides lobules is often blackened in smokers. The medial border of the right lung is nearly vertical, while the left lung contains acardiac notch. The cardiac notch is a concave impression molded to accommodate the shape of the heart.
The Human Lungs Lungs Diagram of a Smoker after Smoking Cancer Anatomy And Heart Drawing Images AFter Smoking Wee of a Weed Smoker
The Human Lungs Lungs Diagram of a Smoker after Smoking Cancer Anatomy And Heart Drawing Images AFter Smoking Wee of a Weed Smoker
The Human Lungs Lungs Diagram of a Smoker after Smoking Cancer Anatomy And Heart Drawing Images AFter Smoking Wee of a Weed Smoker
The Human Lungs Lungs Diagram of a Smoker after Smoking Cancer Anatomy And Heart Drawing Images AFter Smoking Wee of a Weed Smoker
The Human Lungs Lungs Diagram of a Smoker after Smoking Cancer Anatomy And Heart Drawing Images AFter Smoking Wee of a Weed Smoker
The Human Lungs Lungs Diagram of a Smoker after Smoking Cancer Anatomy And Heart Drawing Images AFter Smoking Wee of a Weed Smoker
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