Anatomy & Physiology Circulatory #14


Which blood cell of the circulatory system is responsible for fighting infection?


  1. Leukocytes
    • Rationale:

      Leukocytes are a WBC that circulates in the body’s blood and other fluids. It’s primary role is to fight infection.

  2. Hemoglobin
    • Rationale:

      Hemoglobin is defined as the iron laden blood component that transports oxygen to the cells and tissues within the body.

  3. Erythrocytes
    • Rationale:

      Erythrocytes are red blood cells (RBCs) and play a role in carrying oxygen to the cells within the human body.

  4. Thrombocytes
    • Rationale:

      Thrombocytes are platelets and their primary role is hemostasis.


Infection occurs when bacteria, viruses, or other microbes enter the body and begin to multiply.


Learning Outcomes

Leukocytes are a colorless white blood cell (WBC) that circulates in the blood and body fluids. They are primarily responsible for counteracting foreign substances and disease within the blood. Therefore, they are the blood cell of the circulatory system that is responsible for fighting infection.

Test Taking Tip

Consider the function of each choice to answer this question correctly.

Video Rationale