Final answer:
The simple columnar epithelial cells responsible for absorption in the small intestine are called enterocytes, which have microvilli to increase surface area for nutrient uptake.
Step-by-step explanation:
The simple columnar epithelial cells in the small intestine, specialized for absorption, are known as enterocytes. These cells are vital for the absorption process as they transport nutrients from the lumen of the small intestine into the blood capillaries and lymphatic vessels called lacteals. Microvilli on the apical surface of enterocytes increase the surface area for absorption, which is crucial for efficient nutrient uptake.
Additionally, goblet cells are interspersed with these epithelial cells, secreting mucus that helps protect the intestinal mucosa and eases the passage of contents through the digestive tract.