Here's a breakdown:

* White blood cells are part of the immune system, responsible for fighting infections.

* Phagocytosis is the process by which certain cells engulf and destroy foreign particles, including bacteria.

Here's how it works:

1. Recognition: White blood cells, specifically neutrophils and macrophages, recognize bacteria through surface receptors.

2. Engulfment: The white blood cell surrounds the bacteria, forming a pouch called a phagosome.

3. Fusion: The phagosome fuses with a lysosome, a cellular organelle containing digestive enzymes.

4. Digestion: The enzymes break down the bacteria into harmless components.

5. Excretion: The digested remnants are expelled from the white blood cell.

Other terms related to white blood cell function:

* Chemotaxis: The movement of white blood cells towards the site of infection in response to chemical signals.

* Inflammation: A complex biological response to tissue injury or infection, involving redness, swelling, heat, and pain.

* Immune response: The coordinated action of the immune system to protect the body from foreign invaders.

Let me know if you'd like more information about any of these topics!