Root of the lung
Encyclopedia
A little above the middle of the mediastinal surface of each lung
, and nearer its posterior than its anterior border, is its root, by which the lung is connected to the heart
and the trachea
.
The root is formed by the bronchus, the pulmonary artery
, the pulmonary veins, the bronchial arteries and veins, the pulmonary plexuses of nerves, lymphatic vessels, bronchial lymph glands, and areolar tissue, all of which are enclosed by a reflection of the pleura.
The root of the right lung
lies behind the superior vena cava and part of the right atrium
, and below the azygos vein
.
That of the left lung
passes beneath the aortic arch and in front of the descending aorta
; the phreni pericardiacophrenic artery and vein, and the anterior pulmonary plexus, lie in front of each, and the vagus and posterior pulmonary plexus behind each; below each is the pulmonary ligament
.
The chief structures composing the root of each lung are arranged in a similar manner from before backward on both sides, viz., the upper of the two pulmonary veins in front; the pulmonary artery in the middle; and the bronchus, together with the bronchial vessels, behind.
From above downward, on the two sides, their arrangement differs, thus:
On the right side their position is—eparterial bronchus, pulmonary artery, hyparterial bronchus, pulmonary veins, but on the left side their position is—pulmonary artery, bronchus, pulmonary veins.
The lower of the two pulmonary veins, is situated below the bronchus, at the apex or lowest part of the hilus.
Lung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, 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...
, and nearer its posterior than its anterior border, is its root, by which the lung is connected to the heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
and the trachea
Vertebrate trachea
In tetrapod anatomy the trachea, or windpipe, is a tube that connects the pharynx or larynx to the lungs, allowing the passage of air. It is lined with pseudostratified ciliated columnar epithelium cells with goblet cells that produce mucus...
.
The root is formed by the bronchus, the pulmonary artery
Pulmonary artery
The pulmonary arteries carry deoxygenated blood from the heart to the lungs. They are the only arteries that carry deoxygenated blood....
, the pulmonary veins, the bronchial arteries and veins, the pulmonary plexuses of nerves, lymphatic vessels, bronchial lymph glands, and areolar tissue, all of which are enclosed by a reflection of the pleura.
The root of the right lung
Right lung
The human right lung is divided into three lobes , superior, middle, and inferior, by two interlobular fissures:-Fissures:...
lies behind the superior vena cava and part of the right atrium
Right atrium
The right atrium is one of four chambers in the hearts of mammals and archosaurs...
, and below the azygos vein
Azygos vein
The azygos vein is a vein running up the right side of the thoracic vertebral column. It can also provide an alternate path for blood to the right atrium by allowing the blood to flow between the venae cavae when one vena cava is blocked.-Structure:...
.
That of the left lung
Left lung
The human left lung is divided into two lobes, an upper and a lower, by the oblique fissure, which extends from the costal to the mediastinal surface of the lung both above and below the hilum....
passes beneath the aortic arch and in front of the descending aorta
Descending aorta
The descending aorta is part of the aorta, the largest artery in the body. The descending aorta is the part of the aorta beginning at the aortic arch that runs down through the chest and abdomen. The descending aorta is divided into two portions, the thoracic and abdominal, in correspondence with...
; the phreni pericardiacophrenic artery and vein, and the anterior pulmonary plexus, lie in front of each, and the vagus and posterior pulmonary plexus behind each; below each is the pulmonary ligament
Pulmonary ligament
The root of the lung is covered in front, above, and behind by pleura; at its inferior border, the investing layers come into contact. Here they form a sort of mesenteric fold, the pulmonary ligament, which extends between the inferior part of the mediastinal surface of the lung and the pericardium...
.
The chief structures composing the root of each lung are arranged in a similar manner from before backward on both sides, viz., the upper of the two pulmonary veins in front; the pulmonary artery in the middle; and the bronchus, together with the bronchial vessels, behind.
From above downward, on the two sides, their arrangement differs, thus:
On the right side their position is—eparterial bronchus, pulmonary artery, hyparterial bronchus, pulmonary veins, but on the left side their position is—pulmonary artery, bronchus, pulmonary veins.
The lower of the two pulmonary veins, is situated below the bronchus, at the apex or lowest part of the hilus.