White blood cells (WBCs), or , are the primary defense units of the human immune system. Produced in the bone marrow, these cells circulate through the bloodstream and lymphatic tissues to identify and destroy foreign invaders like bacteria, viruses, and parasites. They typically make up only about 1% of total blood volume but are essential for survival. Types and Functions
The most abundant type (55-70%), serving as the "first responders" to bacterial infections. white cell
The rarest type, which helps prevent blood clots and triggers inflammatory responses during allergies. Histology, White Blood Cell - StatPearls - NCBI Bookshelf White blood cells (WBCs), or , are the