The simple columnar epithelium may be found at the <u>digestive tract and respiratory tract.</u>
In the digestive system, <u>absorption of nutrients</u> mostly occur in the <u>duodenum (part of the small intestines)</u>. This is covered by <u>simple columnar epithelia with microcilia at the apical portion</u>, also called the brush border. The brush border provides the digestive tract a <u>broad surface area to allow optimal nutrient absorption.</u>
In the respiratory system, a specialized type of simple columnar cells, called goblet cells, <u>produce mucus for the mucous membrane to catch or transport foreign objects out of the system</u>. <u>Microcilia is also present</u> at the apical portion of the cell and serves to <u>trap foreign bodies</u> that enter the respiratory tract.