Absorption

Epithelial cells are found in those organs (e.g., small intestine) which are involved in absorption of substances important for life. These cells often have microscopic projections on the apical surface of their plasma membranes called microvilli which increase cell surface area in order to facilitate absorption.
Groups of epithelial cells lining the small intestine are organized into larger finger-like structures called villi which project into the lumen of the gut to further increase its surface area and aid the process of nutrient absorption.