The buffy coat is a thin pale layer found between red cells and plasma after spinning a blood sample in a centrifuge. This layer contains all white blood cells which scientists use to distinguish these immune defenders from other blood components.
A neutrophil nucleus consists of three to five lobes connected by slender strands. These multi-lobed structures allow neutrophils to act as first responders to bacterial or fungal infections while their lifespan ranges from 5 to 135 hours depending on measurement methods.
Eosinophils assume a pink-orange color under eosin staining because their cytoplasm is full of granules that react with the dye. Pathologists use this specific coloration to identify them quickly in tissue samples where they secrete chemicals to destroy large parasites like hookworms and tapeworms.
Basophils represent less than 0.5 percent of the total white blood cell count making them the rarest type of leukocyte found in human circulation. They release histamine to widen blood vessels and secrete heparin an anticoagulant that inhibits clotting during inflammatory responses.
Memory lymphocytes can persist for years while other lymphocyte types last only weeks within the human body. Small lymphocytes measure 7 to 8 micrometers while large ones reach 12 to 15 micrometers and include T cells B cells and natural killer cells as subtypes.