QUICK LOOK
Current knowledge
Mucociliary clearance is the main defense mechanism
of the respiratory system, and it is influenced by several
stimuli, including aerobic exercise and cigarette smok-
ing. Continuous exposure to the chemical substances
contained in cigarette smoke causes epithelial remod-
eling, with an increased number of goblet cells, hyper-
trophy of mucous cells, and the loss of ciliated cells.
This leads to an increase in the production of mucus
and a reduced ability to eliminate it, resulting in im-
paired mucociliary clearance compared with nonsmok-
ers