Search results
Results from the WOW.Com Content Network
Part of the cross section is magnified to show diffusion of oxygen gas and carbon dioxide through type I cells and capillary cells. Gas exchange in the alveolus. Type I cells are the larger of the two cell types; they are thin, flat epithelial lining cells (membranous pneumocytes), that form the structure of the alveoli. [3]
Both lungs have a central recession called the hilum, where the blood vessels and airways pass into the lungs making up the root of the lung. [4] There are also bronchopulmonary lymph nodes on the hilum. [3] The lungs are surrounded by the pulmonary pleurae.
These bronchioles give rise to the air sacs in the lungs called the alveoli. [10] The lungs are the largest organs in the lower respiratory tract. The lungs are suspended within the pleural cavity of the thorax. The pleurae are two thin membranes, one cell layer thick, which surround the lungs. The inner (visceral pleura) covers the lungs and ...
Circulation time through the alveolar capillaries is less than one second, yet 70% of the angiotensin I reaching the lungs is converted to angiotensin II in a single trip through the capillaries. Four other peptidases have been identified on the surface of the pulmonary endothelial cells.
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.
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 blood–air barrier or air–blood barrier, (alveolar–capillary barrier or membrane) exists in the gas exchanging region of the lungs. It exists to prevent air bubbles from forming in the blood , and from blood entering the alveoli .
A capillary is a small blood vessel, from 5 to 10 micrometres in diameter, and is part of the microcirculation system. Capillaries are microvessels and the smallest blood vessels in the body. They are composed of only the tunica intima (the innermost layer of an artery or vein), consisting of a thin wall of simple squamous endothelial cells. [2]