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 classic literature ?
My violent struggles had only accelerated my already dangerously accelerated heart, and increased the need for oxygen in my suffocating lungs.
For instance, a swim-bladder has apparently been converted into an air-breathing lung.
What seemed the centre of the Stranger's form lay open to my view: yet I could see no heart, nor lungs, nor arteries, only a beautiful harmonious Something -- for which I had no words; but you, my Readers in Spaceland, would call it the surface of the Sphere.
I decided to investigate, but first I lifted my head to fill my lungs with the pure, invigorating night air of the mountains.
I opened my mouth wide, and my lungs saturated themselves with fresh particles.
The peculiar V-shaped mouth with its pointed upper lip, the absence of brow ridges, the absence of a chin beneath the wedgelike lower lip, the incessant quivering of this mouth, the Gorgon groups of tentacles, the tumultuous breathing of the lungs in a strange atmosphere, the evident heaviness and painfulness of movement due to the greater gravitational energy of the earth--above all, the extraordinary intensity of the immense eyes--were at once vital, intense, inhuman, crippled and monstrous.
The river was half a mile in width, yet every word uttered by the chieftain was heard; this may be partly attributed to the distinct manner in which every syllable of the compound words in the Indian language is articulated and accented; but in truth, a savage warrior might often rival Achilles himself for force of lungs.
It entered the lungs, and in a few days killed him.
Fancy a girl wanting to follow the hounds when her lungs are so bad
There was no additional strangulation; the noose about his neck was already suffocating him and kept the water from his lungs.
Bowling is good for the stone and reins; shooting for the lungs and breast; gentle walking for the stomach; riding for the head; and the like.
Filling my lungs with air, I dived beneath the surface and swam through the inky, icy blackness on and on along the submerged gallery.