lung

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lung

1. either one of a pair of spongy saclike respiratory organs within the thorax of higher vertebrates, which oxygenate the blood and remove its carbon dioxide
2. any similar or analogous organ in other vertebrates or in invertebrates

Lung

Paired, air-filled respiratory sacs, usually in the anterior or anteroventral part of the trunk of most tetrapods. They lie within the coelom and are covered by peritoneum. In mammals they are within special chambers of the coelom known as pleural cavities and the peritoneum is termed pleura.

Amphibian lungs are often simple sacs, with only small ridges on the internal walls. In higher forms the lungs become more and more subdivided internally, thus increasing greatly the surface areas across which the respiratory exchange takes place. However, even in many reptiles the lungs may be quite simple. Birds have especially complex lungs with a highly differentiated system of tubes leading into and through them to the air sacs which are contained in many parts of the bird's body. Mammalian lungs are simpler, but in them the internal subdivision into tiny sacs or alveoli is extreme; there may be over 350,000,000 of them in one human lung.

In humans the two lungs lie within the chest, separated by the heart and mediastinum. The right lung has three lobes and the left lung two. A bronchus, an artery, and a vein enter each lung medially at the hilum; each branches again and again as it enters the lobules and smaller divisions of the lungs (see illustration). The terminal airways or bronchioles expand into small clusters of grapelike air cells, the alveoli. The alveolar walls consist of a single layer of epithelium and collectively present a huge surface. A small network of blood capillaries in the walls of the alveoli affords surfaces for the actual exchange of gases. See Respiration, Respiratory system

The human lungenlarge picture
The human lung

lung

[ləŋ]
(anatomy)
Either of the paired air-filled sacs, usually in the anterior or anteroventral part of the trunk of most tetrapods, which function as organs of respiration.
References in periodicals archive ?
HFSA launched National Heart Failure Awareness Week in 2000 to raise awareness of this life-threatening disease and to encourage at-risk patients to talk about heart failure with their doctors.
This report shows that some manufacturers and retailers are failing their customers by using nutritional food labels which are overly complex and misleading," said Jane Landon, deputy chief executive of the National Heart Forum.
Communications manager for the National Heart Foundation, Aimee Brock, said nurses from district health boards, primary health organisations, in public health roles and working in regional sports agencies were among those at the conference.
Goldman, Vascular Biology Research Program, Division of Heart and Vascular Diseases, National Heart, Lung, and Blood Institute (NHLBI), 6701 Rockledge Drive, Suite 10192, MSC 7956, Bethesda, MD 20892-0001 USA, 301-435-0560, fax: 301-480-2858, e-mail: goldmans@nhlbi.
Of particular note are several downloadable books, in an easy to read and culturally sensitive format, from the National Heart, Lung, and Blood Institute; they illustrate well the use of the Internet as a publishing tool and not just a means for Web surfing.
For people who are looking to monitor their blood pressure more than once or twice a year, the National Heart, Lung and Blood Institute offers the following suggestions.
No experts--at the American Heart Association; National Heart, Lung, and Blood Institute; or elsewhere--would take that risk.
OUR campaign to raise money for the National Heart Research Fund has been an outstanding success.
For example, several major scientific bodies now recommend "diet, exercise, and behavior therapy" as a standard treatment for obesity (Council on Scientific Affairs 1998; National Heart, Lung, and Blood Institute, 1998, 2000).
The truth is that the Jarvik 2000 devices, at a cost of pounds 60,000 each, were paid for by the National Heart Research Fund.
A study from National Heart, Lung, and Blood Institute's (NHLBI) Framingham Heart Study, reported in the July 1, 1999 issue of The New England Journal of Medicine, indicated that MVP is less common and less serious than previously thought.
New data from the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health, shows that the number of women who die from heart disease has shifted from one in three women to one in four - a decrease of nearly 17,000 deaths from 2003 to 2004.

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