Smoking introduces a host of toxic substances into the body, which can severely affect histological structures. The chemicals in cigarettes, such as nicotine and tar, can cause cellular damage and inflammation. For example, the respiratory epithelium is particularly vulnerable, often showing signs of metaplasia, where normal cells are replaced by abnormal ones. This alteration can lead to chronic obstructive pulmonary disease (COPD) and increase the risk of lung cancer. Histological examinations of smokers' tissues often reveal significant damage compared to non-smokers.
