Cellular protrusions are extensions of a cell's membrane that help it interact with its environment. These structures can take various forms, such as filopodia, lamellipodia, and microvilli. They play crucial roles in processes like movement, communication, and nutrient absorption. These protrusions are made up of proteins and cytoskeletal elements, allowing them to change shape and extend outward. For example, neurons use protrusions to form connections with other cells, while immune cells use them to reach and engulf pathogens. Overall, cellular protrusions are essential for many cellular functions and interactions.