The matches are
A. anatomical barrier is matched with 1. secretion of sweat, saliva, and tears.
The epithelium is a physical barrier constituting one of the first defenses against infectious agents. The desquamation of the epidermis thus eliminates bacteria or other infectious agents that have adhered to the surface of the epithelium. In the digestive tract and the respiratory tract, the movement operated by the peristalsis or the eyelashes contribute to the elimination of the infectious agents. The intestinal flora prevents colonization by pathogenic bacteria acting in particular by competition for nutrients. Tears and saliva also help prevent infection of the eyes and mouth, respectively.
B. physiological barrier is matched with 4. changes in pH and temperature.
In addition to this physical (or anatomical) barrier, the acidic pH and low moisture content of the stratum corneum, and the skin temperature below 37 ° C, are detrimental to bacterial growth. Finally, the presence of antimicrobial peptides and lipids make the epidermis a true defender against infection.
C. phagocytic barrier is matched with 3. signaling to macrophages.
Macrophages are cells belonging to white blood cells (leucocytes), which infiltrate tissues. They come from the differentiation of circulating blood leukocytes, monocytes. Monocytes and macrophages are phagocytes and are therefore capable of phagocytosis.
They participate in innate immunity as a non-specific defense, but are able to participate in adaptive immunity via opsonization.
D. inflammatory barrier is matched with 2. secretion of chemicals.
In an inflammatory reaction, blood flow increases at the lesion area. The blood vessels become more permeable thanks to vasodilator chemical substances, which allows the migration of cells from the blood to the tissues (the call is made using chemokines). The first cells arriving at the site of inflammation are often neutrophils, then macrophages arrive and then lymphocytes if there is immune stimulation.
