Histology, Alveolar Macrophages
Naeem Ahmed, Sachchida Nand, Louisdon Pierre
Abstract
Alveolar macrophages (AM) also known as dust cells are a type of white blood cells. The immune system is divided into the cellular and humoral components. Alveolar macrophages are the first line of defense against invading respiratory pathogens. They reside in pulmonary alveoli and the inter-alveolar septum in close proximity with pneumocytes. The alveoli are the terminal unit of the respiratory system responsible for gaseous exchange. The alveoli are comprised of three different kinds of cells: (1) Type I pneumocytes, build up the structure of the alveolar wall and aid in respiration. They do not replicate. (2) Type II pneumocytes secrete a lipoprotein called surfactant that prevents the collapse of the alveoli even after exhalation. (3) Alveolar macrophages produce a variety of signaling chemicals that interact with other cells of the immune system to orchestrate a response that maintains immunologic and tissue homeostasis in the body . Type II pneumocytes replete both types of pneumocytes and AMs which in turn are vital to host defenses and tissue remodeling