Final answer:
Basophils are the rarest type of granulocyte leukocytes, with large granules that stain dark blue and a two-lobed nucleus. They aid the immune system by releasing histamines and heparin, which contribute to inflammatory responses and prevent blood clotting.
Step-by-step explanation:
Definition of Basophils
Basophils are a type of granulocyte, which are leukocytes (white blood cells) found in the peripheral blood. They are the least common of the white blood cells, usually making up less than one percent of the total leukocyte count. These cells are characterized by their large granules that stain dark blue with basic alkaline stains, making it challenging at times to see their two-lobed nucleus. Basophils are typically 8-10 µm in diameter, slightly smaller than neutrophils and eosinophils. They play a crucial role in the immune system by secreting histamines and heparin - histamines help to dilate and increase the permeability of blood vessels during inflammatory reactions, while heparin inhibits blood clotting and promotes the movement of leukocytes to areas of infection.