Class 11 NEET Biology Structural Organisation in Animals

A macrophage is a type of white blood cell derived from monocytes and is responsible for detecting, engulfing and destroying pathogens and apoptotic cells. They do this by the process called phagocytosis. Fibroblasts are large, flat cells with many branching processes. They secrete collagen fibers. Collagen fibers are unbranched, wavy and arranged in bundles. They contain a proteinous substance called collagen. Mast cells contain heparin and histamine granules in their cytoplasm. Heparin prevents clotting of blood and histamine carry out vasodilation.