Final answer:
The absorption of nutrients in the intestines is primarily carried out by simple columnar epithelial cells, which have specialized adaptations such as microvilli to increase surface area for efficient absorption.
Step-by-step explanation:
The structures responsible for the absorption of nutrients in the intestines are simple columnar epithelial cells. These cells are characterized by their height, which is greater than their width, and are arranged in a single layer. Their nuclei are typically situated closer to the base of the cell. Within this cell type, there are specialized cells known as goblet cells that secrete mucus to lubricate the digestive tract, facilitating the movement and further digestion of food. The simple columnar epithelia in the intestines also feature microvilli, small hair-like projections that significantly increase the surface area for absorption, thus making them highly efficient at absorbing the products of digestion.
The functions of the simple columnar epithelial cells in the intestines include the secretion of digestive enzymes and the absorption of digested nutrients into the bloodstream. This specialized tissue is crucial for efficient digestion and nutrient uptake, ensuring that the body receives the substances necessary for its function and health.