NHA Phlebotomy Certification Practice Exam

Which component of blood helps with immune responses?

1. Erythrocytes

2. Platelets

3. Leukocytes

4. Plasma

The correct answer is: Leukocytes

Leukocytes, or white blood cells, are the primary component of blood that plays a crucial role in the immune response. They are responsible for defending the body against both infectious disease and foreign invaders. There are different types of leukocytes, such as lymphocytes, neutrophils, monocytes, eosinophils, and basophils, each serving specific functions in the immune system. For instance, lymphocytes are vital for adaptive immunity, producing antibodies and remembering pathogens to provide long-lasting immunity, while neutrophils are typically the first responders to infection, engulfing and destroying pathogens. In contrast, erythrocytes, or red blood cells, are mainly involved in transporting oxygen from the lungs to tissues and carrying carbon dioxide back to the lungs for exhalation. Platelets play a key role in blood clotting and wound healing, but do not have a direct role in immune defense. Plasma, the liquid component of blood, contains water, electrolytes, proteins, and nutrients, but it does not directly participate in immune responses. Hence, leukocytes are definitively the component of blood that helps with immune responses.