HESI A2 Anatomy Practice Exam 2026 – Your All-in-One Guide to Exam Success!

The two main types of white blood cells, also known as leukocytes, are lymphocytes and phagocytes. Lymphocytes play a critical role in the immune response, being involved in the recognition and destruction of pathogens, as well as the formation of antibodies. They include T cells, which help regulate immune responses and kill infected cells, and B cells, which produce antibodies that bind to specific antigens.

Phagocytes, which include cells like neutrophils and macrophages, are essential for the innate immune response. They work by engulfing and digesting pathogens and debris in the body, providing an immediate defense against infections.

The other options do not accurately represent the two main types of white blood cells. While erythrocytes (red blood cells) and leukocytes are both components of blood, only leukocytes are white blood cells. Thrombocytes are platelets involved in clotting, and plasma cells are a type of B cell that produces antibodies but are not classified separately as a main type of white blood cell. Thus, focusing on lymphocytes and phagocytes aligns with the fundamental classification of white blood cells and their distinct roles in the immune system.