clipped from www.livescience.com

When a cell undergoes apoptosis, white blood cells called macrophages consume cell debris.

clipped from www.livescience.com

White blood cells, the immune system's "soldiers" for your body, actually crawl along your blood vessels to find their way to infection and injury sites, new research shows.

The cells move like millipedes, creating many minute legs that adhere to the endothelial cells lining blood vessel walls, said researcher Ronen Alon of the Weizmann Institute of Science in Israel. Scientists had previously thought that these cells moved like inchworms, forming attachments at their front and back, then folding in the middle and pushing forward.

Instead, the cells' tiny legs rapidly attach and detach themselves, allowing the cells to quickly migrate to their destination.

When the scientists looked closely at these limb-like protrusions, using an electron microscope, they saw that the legs actually "dig" into the endothelium.