ASCP (American Society for Clinical Pathology) Phlebotomy Technician Certification Practice Exam

Leukocytes, or white blood cells, play a crucial role in the immune system, primarily involved in the recognition and destruction of pathogens such as bacteria, viruses, and other foreign invaders. This function is essential to maintaining the body's health and protecting it from infections.

Leukocytes achieve pathogen destruction through various mechanisms, including phagocytosis, where certain types of leukocytes engulf and digest harmful microorganisms. Others, such as lymphocytes, are responsible for targeting specific pathogens with antibodies or through direct cellular responses. This ability to identify and eliminate threats is fundamental to the adaptive and innate immune responses, ensuring that the body can respond effectively to a wide range of potential infections.

In contrast, the other processes mentioned are not primarily carried out by leukocytes: oxygen delivery is facilitated by red blood cells, nutrient transport is the responsibility of plasma and red blood cells, and hormone regulation is managed by the endocrine system. Thus, the primary function of leukocytes clearly focuses on pathogen destruction, establishing them as vital components of the immune response.