Diffusion: This is the movement of molecules and cells across a concentration gradient, from an area of higher concentration to an area of lower concentration. Cells can use diffusion to move short distances, such as across a cell membrane or through the interstitial fluid (the fluid that surrounds cells).
Cytoplasmic streaming: This is a process by which cells move their cytoplasm and organelles within the cell. Cytoplasmic streaming is driven by the action of motor proteins, which move along microtubules, the cytoskeleton's long, thin structures.
Amoeboid movement: This type of movement is used by cells that have the ability to change shape, such as amoeba and white blood cells. Amoeboid movement involves the extension of pseudopodia, which are temporary extensions of the cell membrane. The pseudopodia then attach to the substrate, and the cell body follows.
Cilia and flagella: Some cells, such as epithelial cells and sperm cells, have cilia or flagella, which are whip-like structures that help to move the cell or propel fluid past the cell. Cilia and flagella are powered by motor proteins that move along microtubules.
Lymphatic system: This is a network of vessels that helps to drain fluid from tissues and organs back into the bloodstream. The lymphatic system also plays a role in transporting immune cells throughout the body, including lymphocytes (white blood cells that fight infection) and antigen-presenting cells (cells that present foreign antigens to lymphocytes).
Bloodstream: Finally, cells can travel through our bodies via the bloodstream. Cells can enter the bloodstream from tissues or organs, or they can be produced in the bone marrow and released into the bloodstream. Once in the bloodstream, cells can be transported to different parts of the body.
