What type of tissue does an expectorant primarily act upon?

An expectorant primarily acts upon respiratory tissue because its main function is to facilitate the clearance of mucus and phlegm from the airways. This is crucial for individuals dealing with respiratory conditions such as bronchitis or colds, where mucus buildup can obstruct breathing and lead to discomfort.

By promoting the thinning of mucus and increasing its production, expectorants help to enhance the ciliary action in the respiratory tract, allowing for easier expulsion of mucus during coughing. Since expectorants target the tissues that line the respiratory passages, their action is directly linked to respiratory health, making respiratory tissue the correct type of tissue affected by these medications.