Smoking causes damage to lungs over time — and it’s permanent
Video
https://metro.co.uk/2018/05/02/nurse-shares-showing-just-bad-smoking-affects-lungs-7514050/amp/
Your lungs contain around 500 million tiny air sacs called alveoli that pull oxygen from the air you breathe and release carbon dioxide when you exhale. Smoking destroys these air sacs by killing the cells that line them.
“Many structures in the body are capable of repairing themselves,” says Karam-Hage. “If you break a bone, for instance, it will eventually mend. If you cut your skin, it will heal. Even the liver can grow back sometimes if a portion of it is removed. But lung tissue doesn’t grow back. Once it’s gone, it’s gone.”
Damage to alveoli gets worse over time, too. And as lung tissue is damaged, it becomes more fibrous, making it harder for people to expand their lungs fully with each inhalation. Less lung tissue and less expansion mean less oxygen getting to all the places it’s needed. That’s why many people don’t think there’s a problem until they start feeling short of breath.
“It happens silently. So, smokers just keep walking around because they don’t feel anything,” says Karam-Hage. “And since people start out with millions of alveoli, it can take 15 or 20 years to lose enough of them to really become obvious. But once you develop something like chronic obstructive pulmonary disease (COPD), there’s no going back. Once you get to that point, you’re never going to get off the oxygen tank.”
Still, Karam-Hage notes, “It really is kind of amazing that some smokers don’t develop lung cancer. Their lungs are getting so much daily exposure to smoke and carcinogens.”
https://www.mdanderson.org/cancerwi...-smoking--3-things-to-know.h00-159540534.html