1. Briefly describe the process of inflammation in an area that has been traumatized.
- Inflammation is the body’s response to tissue damage. Inflammation manifests itself in our bodies as redness, pain, heat, and swelling. It may also result in a loss of function in the injured area or an inability to detect sensations. The inflammatory response has three basic stages: vasodilation and increased blood vessel permeability, phagocyte emigration from the blood into interstitial fluid, and tissue repair. Vasodilation and increased blood vessel permeability occur during the first stage. Vasodilation allows more blood to flow through the damaged area, and increased permeability allows defensive proteins from the blood to enter the injured area. Increased blood flow also aids in the removal of microbial toxins and dead cells. The second step involves phagocyte emigration from the blood into the interstitial fluid and tissue repair. Within an hour after the inflammatory process begins, phagocytes start to appear. As large amounts of blood accumulate, neutrophils begin to adhere to the inner surface of the endothelium (lining) of blood vessels. The neutrophils then start to penetrate the blood vessel's wall and move toward the damaged area. Through phagocytosis, neutrophils attempt to destroy the invading microbes. The neutrophils will die off after a while. However, the inflammatory response continues as monocytes enter the infected area. The monocytes transform into wandering macrophages, which supplement the phagocytic activity of the fixed macrophages that are already present. The macrophages will eventually die off as well. After a few days, a pus (a collection of dead cells and fluid) will form. The pus will be destroyed and absorbed gradually. Tissue repair will follow.
2. Choose one type of Immunity (Innate and Humoral) and explain how its mechanism protects our body.
- Innate immunity includes the physical and chemical barriers provided by the skin and mucous membranes. Internal defenses such as antimicrobial substances, natural killer cells, phagocytes, inflammation, and fever are also included. The first line of defense against pathogens is the skin and mucous membranes of the body. These structures provide both physical and chemical barriers that prevent pathogens and foreign substances from entering the body and causing disease. The epidermis acts as a formidable physical barrier to the entry of microbes. Furthermore, its periodic shedding of epidermal cells aids in the removal of microbes from the skin's surface. Meanwhile, mucous membranes contain mucus, mucus-coated hairs, and cilia that trap many microbes and foreign substances. Other fluids produced by various organs also aid in the protection of the skin's epithelial surfaces and mucous membranes. Tears, saliva, perspiration, gastric juice, urine, and other vaginal secretions are among these fluids. Microbes are also expelled during defecation and vomiting. When pathogens breach the physical and chemical barriers of the skin and mucous membranes, they are met with a second line of defense, which includes internal antimicrobial substances, natural killer cells, phagocytes, inflammation, and fever. Interferons, complement, iron-binding proteins, and antimicrobial proteins are the four main types of antimicrobial substances that all inhibit microbial growth. Interferons prevent viral replication, the complement system encourages phagocytosis, iron-binding proteins inhibit bacterial growth, and antimicrobial proteins eradicate microbes. When microbes penetrate the skin and mucous membranes or bypass the antimicrobial substances in the blood, natural killer cells and phagocytes provide the next nonspecific defense. Natural killer (NK) cells attack any cell in the body that has abnormal or unusual plasma membrane proteins. They kill a wide range of infected body cells as well as some tumor cells. Whereas, phagocytes consume microbes or other particles such as cellular debris. Inflammation attempts to remove microbes, toxins, or foreign material from the site of injury, prevent their spread to other tissues, and prepare the site for tissue repair in order to restore tissue homeostasis. Lastly, fever increases the potency of interferons, inhibits the growth of some microbes, and accelerates body reactions that aid in repair.