Final answer:
Basophils are the white blood cells that release histamine and heparin, substances that contribute to the dilation and increased permeability of blood vessels during inflammation. These cells are involved in body defenses, including allergic and hypersensitivity responses, and are part of a larger inflammatory mediator system.
Step-by-step explanation:
White Blood Cells that Promote Inflammation
The WBC type responsible for releasing histamine and heparin, and promoting inflammation is the basophil. Basophils are characterized by their bilobed nucleus and the presence of granules that release these chemicals. Histamine functions to dilate blood vessels and increase their permeability during an inflammatory response, while heparin is an anticoagulant that helps prevent blood clots and facilitates the movement of leukocytes to the affected area. Basophils, while being the least numerous of the white blood cells, play a critical role in body defenses and are also involved in allergic and hypersensitivity responses.
Moreover, basophils are a part of a larger system of inflammatory mediators, as injured cells and phagocytes such as macrophages and neutrophils also contribute to the inflammatory process by releasing cytokines and other chemicals like prostaglandins and leukotrienes. These substances promote increased vascular permeability and attract white blood cells to the site of injury or infection, contributing to the symptoms of inflammation such as redness, swelling, and pain.