Washington Esthetician State Board Practice Exam

Which cells in the blood are primarily responsible for fighting infections?

1. Red blood cells

2. White blood cells

3. Platelets

4. Plasma cells

The correct answer is: White blood cells

White blood cells, also known as leukocytes, are primarily responsible for fighting infections in the body. These cells play a crucial role in the immune system, identifying and combating pathogens such as bacteria, viruses, and other foreign invaders. There are several types of white blood cells, including neutrophils, lymphocytes, monocytes, eosinophils, and basophils, each with specific functions in the immune response. In contrast, red blood cells are mainly responsible for transporting oxygen from the lungs to the tissues and returning carbon dioxide to be expelled from the body. Platelets are essential for blood clotting and preventing excessive bleeding, while plasma cells are a type of white blood cell that produces antibodies, a component of the immune response, but do not encompass the full scope of white blood cell function. Therefore, the role of white blood cells in directly combating infections establishes them as the key cells in the immune system.