In computer networks and telecommunications, a dedicated line is a communications connection or other hardware resource dedicated to a certain application or use. This is different than a shared connection such as a telephone network or the Internet.
Carbon dioxide, a waste product of metabolism, travels from the blood to the alveoli, where it can be exhaled. Between the alveoli is a thin layer of cells called the interstitium, which contains blood vessels and cells that help support the alveoli. The lungs are covered by a thin tissue layer called the pleura. The same kind of thin tissue lines the inside of the chest cavity -- also called pleura. A thin layer of fluid acts as a lubricant allowing the lungs to slip smoothly as they expand and contract with each breath.
* picture of the heart and its parts. * picture of the body and some of its organs. Location and Structure of the Lungs. The lungs are a pair of elastic, spongy organs used in breathing. In humans the lungs take up a lot of the chest cavity. They are located just behind, and to either side of, the heart. They extend down from the collarbone to the diaphragm (the muscular wall between the chest cavity and the abdominal cavity). In adult humans each lung is 25 to 30 cm.