1 Retina: getting its name from the Latin meaning net, the retina is located at the back of the eye and is where light is detected... 2  more. 3  Trillion: 1,000,000,000,000. 4  Wavelength: a property of photons that determines their energy (how strong they are).We see photons of different wavelengths as different colors.
Emphysema. Emphysema is a long-term, progressive disease of the lungs that primarily causes shortness of breath. In people with emphysema the lung tissues necessary to support the physical shape and function of the lung are damaged.
The most common cause of emphysema is smoking. Pulmonary fibrosis involves scarring, or fibrosis, in the lungs. This process causes air sacs and the supporting lung tissue to become stiff and thick. Fibrosis worsens over time and the lungs are not able to move oxygen into the blood stream.