Name the two major categories of innate nonspecific defenses. Chapter 17: Innate Nonspecific Host Defenses Flashcards 2022-10-09
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The human body has several mechanisms in place to protect itself from harm, including both specific and nonspecific defenses. Nonspecific defenses refer to those that provide broad-spectrum protection against a wide range of potential threats, without requiring the body to specifically recognize or remember a particular pathogen. There are two major categories of innate nonspecific defenses: physical and chemical defenses.
Physical defenses refer to the body's structural and mechanical barriers that protect it from harm. These include the skin, mucous membranes, and cilia (tiny hair-like structures) that line the respiratory, gastrointestinal, and genitourinary tracts. The skin acts as a barrier to physical trauma and environmental damage, while mucous membranes and cilia help to trap and remove foreign particles, such as bacteria and viruses, from the body.
Chemical defenses refer to the body's use of various chemical substances to protect itself from harm. These include antimicrobial peptides, such as defensins and cathelicidins, which are produced by immune cells and help to kill or inhibit the growth of harmful microorganisms. Other chemical defenses include interferons, which are proteins that help to inhibit viral replication, and complement proteins, which help to enhance the activity of certain immune cells.
In summary, the two major categories of innate nonspecific defenses are physical defenses, which include structural and mechanical barriers such as the skin and mucous membranes, and chemical defenses, which include antimicrobial peptides, interferons, and complement proteins. These defenses work together to provide broad-spectrum protection against a wide range of potential threats, helping to keep the body healthy and free from harm.
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Although inflammation is typically associated with negative consequences of injury or disease, it is a necessary process insofar as it allows for recruitment of the cellular defenses needed to eliminate pathogens, remove damaged and dead cells, and initiate repair mechanisms. Following an early neutrophil infiltrate stimulated by macrophage cytokines, more macrophages are recruited to clean up the debris left over at the site. The rise in body temperature also may inhibit the growth of many pathogens since human pathogens are mesophiles with optimum growth occurring around 35 °C 95 °F. Killer cells which have Fc receptors include NK, LAK, and macrophages which have an Fc receptor for IgG antibodies and eosinophils which have an Fc receptor for IgE antibodies. Chemical Barriers Provided by enzymes and other chemical substances in body fluids, these include pepsin and hydrochloric acid in the stomach; tears; lysozyme in tears, saliva, breast milk, and mucus; salt in perspiration; interferons; mucin; defensins; certain lipids in sebum; dermicidin; and complement. They can also be formed by mast cells. Oxygen-dependent myeloperoxidase-dependent intracellular killing Figure 11B As the azurophilic granules fuse with the phagosome, myeloperoxidase is released into the phagolysosome.
Released prostaglandins and kinins contribute to sensitizing effects, and pain relief by aspirin or other anti-inflammatory drugs is based on the inhibition of prostaglandin synthesis. If the nurse elected to be immunized prophylactically, how would you classify the type of that immunization? Excessive inflammation, however, can result in local tissue damage and, in severe cases, may even become deadly. These interferons stimulate nearby cells to stop production of mRNA, destroy RNA already produced, and reduce protein synthesis. Theclassical pathway is the fastest and most effec-tive pathway, beginning with binding of comple-ment protein C1 to an antibody, already attached to its specific antigen, which may be a bacterial cell wall. They also contribute to the five observable signs associated with the inflammatory response: erythema redness , edema swelling , heat, pain, and altered function. Unlike PMNs they do not contain granules but they have numerous lysosomes which have contents similar to the PNM granules.
Name the two major characteristics of adaptive Immunity.
As such, these proteins are not considered part of the early induced immune response, even though they share features with some of the antibacterial proteins of this class. Inflammation is something everyone has experienced. In contrast, the innate immune system does not demonstrate immunological memory. . Macrophages and dendritic cells can reside in body tissues for significant lengths of time. Basophils have cytoplasmic granules of varied size and are named for their granules' ability to absorb the basic dye methylene blue.
It is our immune system that enables us to resist infections. Scavenger receptors Scavenger receptors bind a wide variety of polyanions on bacterial surfaces resulting in phagocytosis of bacteria. The inflammatory reaction brings in phagocytic cells to the damaged area to clear cellular debris and to set the stage for wound repair Figure 21. The extensive scarring observed with hepatitis C infections and liver cirrhosis is the result of chronic inflammation A fever is an inflammatory response that extends beyond the site of infection and affects the entire body, resulting in an overall increase in body temperature. Which of the following is an example of a nonspecific immune defense quizlet? First Line of Defense The most widespread nonspecific defense is the physical barrier we call skin. Molecular markers that make up the major histocompatibility complex MHC are expressed by healthy cells as an indication of "self. Movement due to cilia or peristalsis helps to keep air passages and the gastrointestinal tract free from microorganisms.
21.2 Barrier Defenses and the Innate Immune Response
This recognition triggers an immune response. K cells have on their surface an Fc receptor for antibody and thus they can recognize, bind and kill target cells coated with antibody. Recognition of such cells involves a complex process of identifying inhibitory and activating molecular markers on the surface of the target cell. However, cancer cells and virus-infected cells actively diminish or eliminate expression of MHC markers on their surface. Eosinophils are granulocytes that protect against protozoa and helminths; they also play a role in allergic reactions.
The inflammatory response, or inflammation, is triggered by a cascade of chemical mediators and cellular responses that may occur when cells are damaged and stressed or when pathogens successfully breach the physical barriers of the innate immune system. Differences between the non-specific and specific immune functions 2. Phagocytes such as macrophages have receptors for these proteins, and they are thus able to recognize them as they are bound to the bacteria. However, it is important to note that not all remains of the pathogen are excreted as waste. Prostaglandins cause vasodilation by relaxing vascular smooth muscle and are a major cause of the pain associated with inflammation. There are additional chemical barriers in the respiratory tract mucosae. The wounded area may heal at a superficial level, but pathogens may still be present in deeper tissues, stimulating ongoing inflammation.
Chronic inflammation occurs when the inflammatory response is unsuccessful, and may result in the formation of granulomas e. As a result of fever, the spleen and liver keep iron and zinc away from the rest of the body somewhat so they cannot be used to sup-port bacterial growth. Cells are repaired more quickly because fever increases their metabolic rate. The C1 complex is a multipart protein complex, and each component participates in the full activation of the overall complex. Phagocytic cells such as macrophages and neutrophils are attracted to an infection site by chemotactic attraction to smaller complement fragments. What is a nonspecific response? Cytokines and Chemokines A cytokine is signaling molecule that allows cells to communicate with each other over short distances.
Chronic inflammation can be an important cause of tissue damage from viral infections. Basophils and also mast cells release histamine 4. Thus, even though the initial cell is sacrificed, the surrounding cells are protected. If apoptosis is induced before the virus has the ability to synthesize and assemble all its components, no infectious virus will be released from the cell, thus preventing further infection. The process by which circulating complement precursors become functional is called complement activation. Plants use PRRs to recognize conserved microbial signatures.
Consist of a layer of epithelial cells bound by tight junctions. These include neutrophils PMNs , eosinophils, and basophils. Fever Fever is the elevation of body temperature that reduces iron in the blood, which inhibits bacterial and fungal reproduction; fever also causes increased phagocy-tosis by macrophages. The expelled mucus is then swallowed and destroyed in the stomach, or coughed up, or sneezed out Figure 17. The redness and heat of inflammation are caused by vasodilation.
