Search results
Results from the WOW.Com Content Network
A pulmonary artery is an artery in the pulmonary circulation that carries deoxygenated blood from the right side of the heart to the lungs.The largest pulmonary artery is the main pulmonary artery or pulmonary trunk from the heart, and the smallest ones are the arterioles, which lead to the capillaries that surround the pulmonary alveoli.
The pulmonary arteries carry deoxygenated blood to the lungs, where carbon dioxide is released and oxygen is picked up during respiration. [3] Arteries are further divided into very fine capillaries which are extremely thin-walled. [4] The pulmonary veins return oxygenated blood to the left atrium of the heart. [3]
Arteries branch into small passages called arterioles and then into the capillaries. [19] The capillaries merge to bring blood into the venous system. [ 20 ] The total length of muscle capillaries in a 70 kg human is estimated to be between 9,000 and 19,000 km. [ 21 ]
The lungs stretch from close to the backbone in the rib cage to the front of the chest and downwards from the lower part of the trachea to the diaphragm. [1] The left lung shares space with the heart, and has an indentation in its border called the cardiac notch of the left lung to accommodate this.
In the lungs, special mechanisms have been adapted to meet the needs of increased necessity of blood flow during exercise. When the heart rate increases and more blood must flow through the lungs, capillaries are recruited and are also distended to make room for increased blood flow. This allows blood flow to increase while resistance decreases.
Bronchial arteries carry oxygenated blood to the lungs; Pulmonary capillaries, where there is exchange of water, oxygen, carbon dioxide, and many other nutrients and waste chemical substances between blood and the tissues; Bronchial veins drain venous blood from the large main bronchi into the azygous vein, and ultimately the right atrium.
The capillaries are responsible for allowing the blood to receive oxygen through tiny air sacs in the lungs. This is also the site where carbon dioxide exits the blood. This all occurs in the lungs where blood is oxygenated. [28] The blood pressure in blood vessels is traditionally expressed in millimetres of mercury (1 mmHg = 133 Pa).
The bronchial arteries supply blood to the bronchi and connective tissue of the lungs. They travel with and branch with the bronchi, ending about at the level of the respiratory bronchioles. They anastomose with the branches of the pulmonary arteries, and together, they supply the visceral pleura of the lung in the process.