- Briefly describe the process of inflammation in an area that has been traumatized.
- Choose one type of Immunity (Innate and Humoral) and explain how its mechanism protects our body.
Inflammation is our body’s defensive mechanism in response to tissue damage. It is an attempt to dispose the foreign materials or pathogens at the site of injury and prepare the area for tissue repair. The process of inflammation includes 3 basic stages:
1) Vasodilation and increased blood vessel permeability.
- When there is tissue damage, vasodilation of arterioles and increased permeability of capillaries occur. The vasodilation allows more blood to flow through the site of injury and increased permeability allows defensive proteins and blood-clotting factors to go to the damaged area. As a result, pain, redness, swelling and heat in site of injury may occur. Histamine, kinins, prostaglandins, leukotrienes, and complement help in this stage of inflammatory response.
2. Emigration (movement) of phagocytes from the blood into interstitial fluid
- Within an hour after the process starts, phagocytes attach on the inner surface of endothelial lining of blood vessels. They squeeze through the wall to reach the injured area in a process called emigration. The first to appear on site are the neutrophils which functions to destroy microbes by phagocytosis. As the inflammatory response continues, monocytes follow the neutrophils to the infected area and transform into macrophages to engulf damaged tissues, worn-out neutrophils, and invading microbes.
3. Tissue repair
- The damaged tissue is already covered by the blood-clotting factors and is healing.
2) Innate or nonspecific immunity includes the external physical and chemical barriers (first line of defense) and internal defenses (second line of defense). The first line of defense is the skin and mucous membranes. The skin serves as the physical barrier that prevents pathogens, and foreign materials from entering the body. On the other hand, the mucous membranes traps and filters microbes, dust, and pollutants from inhaled air in the nose and upper respiratory tract. Other chemicals and mechanisms in the first line of defense include: lacrimal apparatus, saliva, lysozyme, vaginal secretions, defecation, vomiting, perspiration, sebum, and gastric juices in the stomach.
When some microbes and pathogens bypass our body’s first line of defense, they encounter a second line of defense: internal antimicrobial substances, phagocytes, natural killer cells, inflammation, and fever. Interferons, complement, iron-binding proteins, and antimicrobial proteins are antimicrobial substances that prevent microbial growth. On the other hand, phagocytes and natural killer cells attack any cells that are infected or abnormal. Additionally, inflammation aid in tissue repair and fever intensifies the effects of interferons by speeding up body reactions that speed up repair.