nonpolar covalent bond. (physical chemistry). A bond in which a pair of electrons is distributed or shared equally between two atoms. 1  Facebook.2  Twitter.onpolar covalent bond. (physical chemistry). A bond in which a pair of electrons is distributed or shared equally between two atoms. 1  Facebook.
When is a barrel chest a sign of a disease process? Chronic obstructive pulmonary disease (COPD) is the most common instance in which a barrel chest will occur. In these cases, itâs a sign of the lungs being over-expanded. This is caused by the loss of elasticity and results in the person having hyper-inflated lungs.
What Causes COPD? Long-term exposure to lung irritants that damage the lungs and the airways usually is the cause of COPD. In the United States, the most common irritant that causes COPD is cigarette smoke. Pipe, cigar, and other types of tobacco smoke also can cause COPD, especially if the smoke is inhaled. Breathing in secondhand smoke, air pollution, or chemical fumes or dust from the environment or workplace also can contribute to COPD. (Secondhand smoke is smoke in the air from other people smoking.)