Canadian Society for Medical Laboratory Science (CSMLS) Practice Exam

What is the primary role of leukocytes in the body?

1. Transport oxygen

2. Fight infection

3. Clot blood

4. Regulate body temperature

The correct answer is: Fight infection

Leukocytes, also known as white blood cells, play a crucial role in the immune system, primarily responsible for fighting infections and protecting the body against pathogens such as bacteria, viruses, fungi, and parasites. These cells are key components of the immune response; they recognize and target foreign invaders, enabling the body to respond effectively to infections. Leukocytes can be further categorized into various types, including neutrophils, lymphocytes, monocytes, eosinophils, and basophils, each with specialized functions in immune defense. For example, neutrophils are often the first responders to microbial infection, while lymphocytes, such as T cells and B cells, are vital for adaptive immunity, allowing for a more targeted and lasting response. This ability to combat infection makes the role of leukocytes essential for maintaining health and preventing the spread of disease within the body. Other processes mentioned, such as oxygen transport, blood clotting, and regulating body temperature, are carried out by erythrocytes (red blood cells), platelets, and various physiological mechanisms, respectively, and do not pertain to the primary function of leukocytes.