What are the mobile units formed in the bone marrow that travel through the blood referred to as?

The mobile units formed in the bone marrow that travel through the blood are referred to as leukocytes. Leukocytes, or white blood cells, play a crucial role in the body's immune response by defending against infection and disease. They are produced in the bone marrow and released into the bloodstream, allowing them to move to sites of infection or inflammation throughout the body.

Categories within leukocytes include lymphocytes, monocytes, neutrophils, eosinophils, and basophils, each with specific functions related to the immune system. They are distinguished from erythrocytes, which are red blood cells responsible for oxygen transport, and granulocytes, which are a subtype of leukocytes that contain granules in their cytoplasm, including neutrophils, basophils, and eosinophils.

Understanding the role of leukocytes is essential for recognizing how the immune system operates and how it responds to various health challenges, which is why this term specifically applies to the mobile units described in the question.