Final answer:
White blood cells (WBCs) or leukocytes are the formed elements in blood responsible for destroying bacteria and viruses, being an essential part of the body's immune system with various types contributing to this defense mechanism.
Step-by-step explanation:
The formed element in the blood responsible for destroying bacteria and viruses is the white blood cells (WBCs), also known as leukocytes. These cells are a critical component of the body's immune system. There are different types of white blood cells, including neutrophils, monocytes, lymphocytes, eosinophils, and basophils, which all play unique roles in the immune response. Neutrophils, for example, are the most abundant type of leukocytes and act as first responders to infection, especially bacterial infections. They destroy infectious agents by various mechanisms, such as phagocytosis, degranulation, and the release of enzymes.
Plasma is the fluid component of blood that contains water, plasma proteins, electrolytes, and other solutes but does not play a direct role in destroying bacteria and viruses. Red blood cells (RBCs), or erythrocytes, are primarily responsible for carrying oxygen to body tissues and do not have immune functions. Platelets, or thrombocytes, are involved in blood clotting and also do not directly combat pathogens.
Blood is composed of these formed elements and plasma, with each component having distinct roles in maintaining health. Haemoglobin within RBCs, for example, is essential for oxygen transport, while leukocytes are indispensable in defending the body against pathogens, and platelets are key in hemostasis. To maintain health, the body continues to produce these cells through hemopoiesis, a process that begins in the red bone marrow.