Portage Pathophysiology Module 3: Innate and Adaptive Immunity Exam, Exams of Nursing

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Portage Pathophysiology Module 3

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define innate immunity - Answer Innate immunity, also called natural immunity, is the first line of defense. This type of defense is in place before an infection takes place and can function immediately. It is comprised of physical, chemical, cellular, and molecular defenses. How does the skin act as a physical barrier? - Answer The skin's design makes it a strong physical barrier. It has closely packed cells in multiple layers that are continuously being shed. Keratin covers the skin, which creates a salty, acidic environment inhospitable to microbes. It also contains antimicrobial proteins and lysozymes that inhibit microorganisms and help to destroy them. What cells are involved in innate immunity? - Answer neutrophils, macrophages, dendritic cells (DC), natural killer (NK) cells, and intraepithelial lymphocytes. Describe each type of leukocyte and explain their function: - Answer Neutrophils are the most abundant in the body and are an early responder in innate immunity and use phagocytosis to kill microbes. Eosinophils are active in parasitic infections and allergic responses. Basophils release histamine and proteolytic enzymes. Monocytes are the largest in size and are released from the bone marrow and mature into macrophages and dendritic cells where they engage in the inflammatory response and phagocytize foreign substances and cellular debris. Macrophages have a long life span, reside in the tissues, and are the first phagocyte that organisms encounter. Neutrophils and macrophages work together on behalf of the host's initial defense system. Describe adaptive immunity: - Answer Adaptive immunity, also called acquired immunity, is the second line of defense and includes both humoral and cellular mechanisms that respond to cell-specific substances known as antigens. Adaptive immunity is acquired through previous exposure to infections and other foreign agents. It can not only distinguish self from nonself but can recognize and destroy specific foreign agents based on their different antigenic properties. This response takes more time but is extremely effective. What are antigens? - Answer Antigens are present on the surface of pathogens or other foreign substances that elicit the adaptive immune response.

What are the primary cells of adaptive immunity? - Answer lymphocytes, APCs (antigen presenting cells), and effector cells. Describe B & T lymphocytes and discuss their role in immunity: - Answer B lymphocytes produce the antibodies (humoral immunity) and T lymphocytes provide the cell-mediated immunity. B and T lymphocytes have the unique function as the only cells to recognize specific antigens present on the surface of pathogens and to remember them in the future. What is the function of humoral immunity? - Answer B lymphocytes function in humoral immunity to produce antibodies. What is the function of cellular immunity? - Answer T lymphocytes make up the cellular immunity and function to activate other T and B cells, control intracellular viral infections, reject foreign tissue grafts, activate autoimmune processes, and activate delayed hypersensitivity reactions. What is the master regulator of the immune system? - Answer CD4+ helper T cells Describe the differences between active and passive immunity? - Answer active is acquired from an immune response via vaccination or environmental exposure. The host's own immune system initiates immune response and developed memory. Passive is through another source, such as a mother's breast milk What are type I hypersensitivity reactions? - Answer IgE-mediated reactions that develop quickly upon exposure to an antigen What cells are involved in type I reactions? (Know their roles.) - Answer Mast cells, basophils, and eosinophils play an important role in the development of type I reactions because they contain the chemical mediator histamine. What are type II hypersensitivity reactions? - Answer Type II hypersensitivity reactions, or cytotoxic hypersensitivity reactions, are antibody-mediated reactions. They are mediated by IgG or IgM antibodies directed against target antigens on specific host cell surfaces or tissues.

What are autoimmune disorders? - Answer Autoimmune diseases occur when the body's immune system fails to differentiate self-antigens from nonself antigens and mounts an immunologic response against host tissues. What is self-tolerance? - Answer The ability to distinguish self from non-self is termed self-tolerance What is autoreactivity? - Answer describes an organism acting against its own tissue What is anergy? - Answer When the loss of lymphocyte response to an antigen occurs and causes a lack of cellular and/or humoral immunologic response, this is called anergy. Anergy is the state of immunologic tolerance to specific antigens. What are autoantibodies? - Answer In many autoimmune diseases, the immune system loses its ability to recognize self and produces what is called autoantibodies. What are positive and negative selection? - Answer During maturation in the thymus, T cells encounter self-peptides bound to MHC molecules. The T cells that display the host's MHC antigens and T-cell receptors for a nonself-antigen are allowed to mature, a process termed positive selection. The T cells that have a high affinity for host cells are sorted out and undergo apoptosis, called negative selection. What are the 2 general causes of autoimmune diseases? - Answer genetic and environmental factors How do you diagnose an autoimmune disease? - Answer Diagnosis is made by history, physical, and serological findings. What is Graves' disease? - Answer It is an abnormal stimulation of the thyroid gland by thyroid- stimulating antibodies (TSH receptor antibodies) that act through the normal TSH receptors. It is a state of hyperthyroidism, goiter, and ophthalmopathy. What is SLE? - Answer Systemic lupus erythematosus (SLE) is a chronic inflammatory disease termed the great imitator because it can affect almost any organ system.

What is HIV? - Answer HIV is a retrovirus that selectively attacks the CD4+ T lymphocytes, the immune cells responsible for coordinating the immune response to infection. Because of this, people with HIV infection are more susceptible to severe infections with ordinarily harmless organisms. How is HIV spread? - Answer HIV is transmitted from one person to another through sexual contact, blood-to-blood contact, or from mother to child during pregnancy, birth, or breastfeeding. HIV is not spread via saliva or causal contact. What is seroconversion? - Answer Seroconversion is the term when an infected person's blood converts from being negative for HIV antibodies to being positive. What is the window period? - Answer The time between infection and seroconversion is called the window period. What is the latent and last phase of HIV infection? - Answer The latent phase is characterized by no signs or symptoms of illness. The last phase, or AIDS illness, occurs when the CD4+ cell count falls to less than 200 cells/μL or exhibits an AIDS-defining illness. What are opportunistic infections? - Answer Opportunistic infections are those common organisms that do not produce infection without impaired immune function. Describe the different diagnostic methods for HIV. - Answer The best diagnostic method to detect HIV is the HIV antibody test, known as the enzyme immunoassay (EIA), or ELISA. If positive, it is followed by the confirmatory test, the Western blot assay. The EIA detects antibodies produced in response to HIV infection. The polymerase chain reaction (PCR) test is a nucleic acid test that can detect HIV DNA. It tests for the presence of the virus, rather than the antibody, which is helpful in diagnosing HIV infection in infants born to infected mothers. These infants would have their mother's antibodies whether or not they have been infected. What are the cardinal signs of inflammation? - Answer Rubor - redness (caused by dilation of vessels) Tumor - swelling (due to extravascular accumulation of fluid) Calor - heat (caused by increased blood flow) Dolor - pain (d/t increased pressure from accumulation of fluid and mediators)

Functio laesa - loss of function What are the 2 phases of acute inflammation? - Answer vascular and cellular phase What are the steps in the cellular phase? - Answer Adhesion and margination, transmigration, and chemotaxes Describe the process of chronic inflammation and discuss how it often develops. - Answer Chronic inflammation may result from recurrent or progressive acute inflammatory process or from low-grade responses that fail to evoke an acute response. It involves the collection of macrophages and lymphocytes instead of neutrophils. It also involves the proliferation of fibroblasts instead of exudates. What are the 3 stages of wound repair? - Answer There are three general stages of wound healing: (1) the inflammatory phase, (2) the proliferative phase, and (3) the wound contraction and remodeling phase. What factors can inhibit wound repair? - Answer Factors that affect wound healing negatively include malnutrition, decreased blood flow and oxygen delivery, impaired inflammatory and immune responses, infection, wound separation, foreign bodies, and age.