Mikrovillidel

Mikrovillidel are microscopic, finger-like projections that extend from the surface of certain cells. Their primary function is to significantly increase the surface area available for absorption or secretion. These structures are commonly found on epithelial cells lining the small intestine, where they greatly enhance the absorption of nutrients from digested food. They are also present in the kidneys, aiding in the reabsorption of water and solutes.

Each microvillus is covered by a plasma membrane and contains a core of actin filaments. These filaments are anchored to a network of intermediate filaments within the cell's cytoplasm, providing structural support. The increased surface area provided by mikrovillidel can be up to 20 times greater than that of a smooth cell surface. This amplification is crucial for efficient cellular processes that rely on transport across the cell membrane.

The arrangement of mikrovillidel can vary depending on the cell type and its specific function. In some cases, they form a dense brush border, while in others, they may be more sparsely distributed. Their presence is a key adaptation for cells involved in absorption, secretion, and other transport-related activities.