With eye pain, there may be other symptoms too, which may help diagnose the cause of the discomfort. These include: 1  Conjunctivitis-red itchy eyes. 2  Tears. 3  Light sensitivity (photophobia). 4  Discharge, which can be clear, or thick and coloured (pus). 5  The eye being crusted shut after sleep due to discharge.
The process of breathing performs a number of important gas exchanges through inhalation and exhalation. When someone inhales, they contract and move their diaphragm, which allows the lungs to expand. This is a part of the process needed to psychically suck in the air. When a person exhales, the diaphragm relaxes and the movement is undone. This allows air to be gradually pushed out of the lungs.
In humans breathing 100 percent oxygen at normal pressure, here's what happens: Fluid accumulates in the lungs. Gas flow across the alveoli slows down, meaning that the person has to breathe more to get enough oxygen. Chest pains occur during deep breathing. The total volume of exchangeable air in the lung decreases by 17 percent.