Pseudópodo

Pseudópodo is a term derived from Greek, meaning "false foot." It refers to a temporary, protoplasmic extension of the cell surface of certain unicellular organisms, such as amoebas, and some multicellular cells like white blood cells. These extensions are formed by the dynamic rearrangement of the organism's cytoskeleton, primarily actin filaments, and are crucial for locomotion and phagocytosis.

The formation of a pseudópodo typically involves the streaming of cytoplasm towards a specific region of the cell membrane. This process is often guided by chemical signals or environmental cues. Once extended, the pseudópodo can adhere to a surface, allowing the organism to pull itself forward. In the context of phagocytosis, pseudópodos can surround and engulf food particles or foreign bodies, forming a food vacuole within the cell.

The shape and duration of pseudópodos can vary greatly depending on the cell type and its function. In amoebas, they are often broad and lobed, while in white blood cells, they can be more slender and finger-like. The ability to form pseudópodos is a fundamental characteristic of organisms that exhibit amoeboid movement, a type of locomotion that is essential for processes like immune surveillance and tissue repair.