White blood cells (WBCs), or leukocytes, are a crucial part of the immune system. They help the body fight infections and diseases by identifying and attacking harmful pathogens like bacteria and viruses. There are several types of white blood cells, each with specific functions, including neutrophils, lymphocytes, and monocytes. WBCs are produced in the bone marrow and circulate throughout the body in the bloodstream and lymphatic system. When an infection occurs, white blood cells quickly move to the affected area to combat the invaders, helping to maintain overall health and protect the body from illness.