How do lung cancer and tuberculois(in the lungs) affect gas exhange in the lungs(between alveoli and the blood

Answer 1

So essentially you're question is how is lung "diffusion" impaired with cancer and TB?

Objectively, impairment can be measured by DLCO, which is part of Pulmonary Function Testing. It will tell you how much of a trace gas was taken in by your pulmonary system... the "less" trace gas returned to the PFT machine, the better the diffusion. When "more" trace gas is returned to the PFT machine, it implies your body did not absorb (exchange) the trace gas and therefore poorer diffusion.

So the question would be, what causes the poor gas exchange? Usually scarring. You can probably do a Wiki search on Pulmonary Fibrosis, or Interstitial Lung Disease.

With lung cancer, it may not necessarily be the cancer that causes the poor gas exchange. The "treatment" for cancer is usually the cause. Your typical cancer treatments are usually chemotherapy and/or radiation. Both of which, in the long term, cause tissue damage. These tissues do heal, but leave scars behind. These scarred tissues are typically thicker than the tissues they replaced. This is what causes the impaired gas exchange.... as thicker tissues are less permeable to gas as thinner tissues (just like a Mylar Balloon versus a Latex Ballon). Mylar Ballons are less permeable, therefore they stay afloat longer than their Latex Counterparts. Probably not the best analogy, but you can figure it out.

For TB, it's the same. Lungs get damaged, then heal, but leave scarring resulting in impaired gas exchange.

You can also include things like mis-use of Antibiotics, or Asbestos exposure.

Alveoli are wrapped with capillaries... imagine a balloon wrapped in a fabric mesh. The Alveoli are the balloons and the capillaries the mesh. That would be normal blood and gas communication. Now imagine the balloon with a thicker layer between it and the mesh. Again, not the best analogy, but it should give you an ideal of how gas exchange is impaired with Interstitial Lung Disease. With the thicker tissue, there is clearly poorer communication with the capillary mesh.

Is this for a school project? Good luck.