Which formed element is most numerous in the blood?

The most numerous formed element in the blood is red blood cells, also known as erythrocytes. These cells play a crucial role in the body by transporting oxygen from the lungs to tissues and returning carbon dioxide from the tissues back to the lungs for exhalation. In a healthy adult, red blood cells typically number around 4.5 to 6 million cells per microliter of blood, greatly outnumbering white blood cells and platelets, which are also vital to bodily functions.

White blood cells are part of the immune system and responsible for protecting the body against infections, whereas platelets are important for blood clotting and repair of damaged blood vessels. Plasma cells, which are a type of white blood cell, specifically produce antibodies but are not a category of formed elements like red blood cells, white blood cells, or platelets.

Thus, the overwhelming prevalence of red blood cells in the bloodstream makes them the most numerous formed element, essential for maintaining adequate oxygen levels and supporting cellular respiration in the body.