Biology Study Guide Final Exam Chapter 43

Biology Study Guide Final Exam Chapter 43 - Study Guide:...


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Study Guide: Final Exam Chapter 43: Immune Response 1. Nonspecific defense is known as innate immunity, a defense that is present before any exposure to pathogens and is effective from the time of birth. They are nonspecific, quickly recognizing and responding to a broad range of microbes regardless of identity. The second type of immunity is acquired immunity which comes about after exposure to certain pathogens. The white blood cells that detect this are lymphocytes and produce two types of immune responses. In the humoral response, antibodies bond to the foreign cell and mark them for identification. In the cell-mediated response, cytotoxic lymphocytes directly destroy the cells or tissue. 2. Examples of nonspecific disease include external barriers formed by the skin and mucous membranes and a set of internal cellular and chemical defenses that combat infectious agents that breach the barriers. Key players are macrophages, which ingest and destroy pathogens. 3. Phagocytosis is the digestion of invading microorganisms by white blood cells known as phagocytes. Some lymphocytes are neutrophils, macrophages, eosinophils and dendritic cells. Other microbial proteins include about 30 proteins that make up the complement system (which is inactive when bacteria are not present). Interferons, both alpha and beta, attack viruses and prevent them for spreading. Another group, defensins, damage broad groups of pathogens without harming body cells. 4. Natural killer cells patrol the body and aatach virus-infected body cells and cancer cells. Once one of these cells attaches to a virus cell, it releases chemicals that lead to the death of the cell by apoptosis, or programmed cell death. Although not 100%, it is helpful in the prevention of disease. This chemical death is different than phagocytosis (ingestion). 5. Inflammatory response is brought about when there is damage to tissue by physical injury or the entry of pathogens. One of the active chemicals involved is histamine, which is stored in mast cells found in connective tissues. This increased blood flow causes the redness ad heat typical of inflammation. 6. Although painful, this swelling and increased blood flow is critical to innate defense. An increased blood flow means there are increased clotting factors and phagocytes being brought to the area. This means that the infection and foreign bacteria will be swallowed by the phagocytes and prevent infection to surrounding tissues. 7. Some chemicals involved with inflammatory response are small proteins called chemokines. Chemokines direct the migration of phagocytes and signal them to increase their microbe-killing compounds. 8. Lymphocytes are the key cells of acquired immunity, the second major defense of the body.Any molecule that elicits a response from a lymphocyte is known as an antigen. Antibodies bind to antigens and destroy them. There are two main types of lymphocytes: B lymphocytes (B cells) and T lymphocytes (T cells). They recognize foreign cells by means of antigen-specific receptors embedded in their membranes. A
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