Anatomy and Physiology II Practice Test

The primary defender against parasites is the eosinophil, which is a type of white blood cell. Eosinophils play a crucial role in the immune response against multicellular parasites, such as helminths (worms), and are also involved in allergic reactions. They achieve this by releasing cytotoxic granules containing enzymes and proteins that are effective at attacking and breaking down the membranes of these larger pathogens.

In addition to fighting off parasites, eosinophils participate in inflammatory processes and help modulate the immune response, making them essential in the body's defense mechanisms. Their numbers often increase in response to parasitic infections and allergic conditions, highlighting their specific role in these processes.

While other types of white blood cells have different functions, they do not primarily target parasites in the same way. Erythrocytes, for instance, are red blood cells responsible for oxygen transport. Basophils are involved in inflammatory and allergic reactions, releasing histamine, while neutrophils primarily deal with bacterial infections through phagocytosis. Hence, eosinophils are specifically tailored for combating parasitic infections and are the most relevant choice for this question.