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Portage Pathophysiology Module 3
Problem Set.
Immunity - ANSWERprotection from infectious disease Immune response - ANSWERThe coordination of cells to provide protection Innate immunity - ANSWERAKA - 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.
- It is generalized and non-specific How does the skin act as a physical barrier? - ANSWERThe 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
- intraepithelial lymphocytes Where are cells of innate immunity derived from? - ANSWERhematopoietic stem cells in the bone marrow Leukocytes - ANSWERWhite blood cells that are heavily involved in innate immune response What are the 2 categories of leukocytes? What type of leukocyte goes in each category? - ANSWERGranulocytes: (contain granules)
- Neutrophils
- Basophils
- Eosinophils Agranulocytes: (lack granules)
- Lymphocytes
- Monocytes
- Macrophages Neutrophils - ANSWER- most abundant cell in the body,
- are the first phagocyte that organisms encounter
- Neutrophils and macrophages work together on behalf of the host's initial defense system. Natural killer (NK) cells and Intraepithelial cells (IELs) - ANSWER- can kill some types of tumor and/or infected cells without previous exposure to surface antigens
- NK cells can spontaneously kill target organisms
- NK cells help with dendritic cell maturation Dendritic cells (DCs) - ANSWER- found as immature cells in lymphoid tissue.
- Here they capture foreign agents and transport them to peripheral lymphoid organs. Once activated, they undergo a complex maturation process as they migrate to the regional lymph nodes. An important role is their function as key antigen-presenting cells (APCs) capable of initiating adaptive immunity. They serve an important role between innate and adaptive immunity. Describe adaptive immunity: - ANSWER- acquired immunity - the second line of defense
- Includes both humoral and cellular mechanisms that respond to cell-specific substances known as antigens.
- acquired through previous exposure to infections and other foreign agents. (takes time and repeated exposure)
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? - ANSWERforeign substances that elicit an adaptive immune response when present in the body. examples: bacteria, fungi, viruses, protozoa, parasites, plant pollens, insect venom, and transplanted organs Antigenic determinants or epitopes - ANSWER- Antigens have immunologically active sites
- Lymphocytes and antibodies (immunoglobulins) have specific receptors that recognize and bind to these sites Adaptive immunity is comprised of what two interrelated forms of immunity?
- ANSWERHumoral Immunity (B-lymphocytes) Cell-mediated Immunity (T-lymphocytes) Humoral Immunity - ANSWER- mediated by B-lymphocyte activation and subsequent antibody production.
- the main defense against extracellular microbes and toxins. Cell-mediated immunity - ANSWER- involves activation of specific T- lymphocytes (T-helper and T- cytotoxic lymphocytes)
Describe B & T lymphocytes and discuss their role in immunity: - ANSWER- B lymphocytes produce the antibodies (humoral immunity)
- T lymphocytes provide cell-mediated immunity.
- only cells in the body that can distinguish and recognize specific antigens present on the surface of pathogens They have receptors with specific proteins that correlate with specific cell functions. CD "Cluster of Differential" - these are surface molecules that are given a number to describe a specific surface protein. (CD4 or CD8) are then recognized by antibodies. 371 clusters exist. T and B lymphocyte properties necessary for the adaptive immune response:
- ANSWER- Specificity
- Diversity
- Memory
- Recognition What is the function of humoral immunity? What are the two waves of response? - ANSWERB lymphocytes function in humoral immunity to produce antibodies. 2 waves of response:
- Primary immune response - body first encounters a foreign antigen
- Secondary immune response, (also referred to as that memory phase), occurs on repeated exposure to the antigen
Immunoglobulins (Ig) and their 5 classes - ANSWERAntibodies
- IgG (Gamma globulin) - 75%
- IgA - 15%. Secretory Ig found in saliva, tears, colostrum, and bronchial, GI, prostatic, and vaginal secretions. Provides immunity and stops the attachment of microbes on epithelial surfaces.
- IgM - 10%. Lysis of microorganisms. First Ig produces in response to an infection. The first antibody to be produced by the fetus and immature B lymphocytes.
- IgD - low levels and function unknown
- IgE - least common and responsible for inflammation and allergic responses, combating parasitic infections. What is the function of cellular immunity? - ANSWERT 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? - ANSWERCD4+ helper T cells Central and peripheral lymphoid organs - ANSWERCentral organs - bone marrow and thymus Peripheral - lymph nodes, spleen, tonsils, appendix. mucosa-associated lymphoid tissues in the respiratory, GI, and reproductive systems
Types I hypersensitivity reactions - ANSWERAllergic Rhinitis - Asthma - Anaphylaxis - Primary early response (Type 1) - ANSWER- begins 5 to 30 min of allergen exposure and subsides within 60 minutes. (CD4 T2H (Helper T cells) stimulates B cells to lead to IgE secretion from plasma cells.) Primary - production of IgE and mast cell sensitization. Antigens bind to mast cells and degranulate to release mediators (histamines and heparin). Secondary late response (Type 1) - ANSWER- occurs 2 to 8 hours after resolution of the initial phase and can last several days. (CD4 T2H (Helper T cells) stimulates B cells to lead to IgE secretion from plasma cells.)
- mast cells produce cytokines and membrane phospholipids. Cytokines - promote the migration of eosinophils and leukocytes to the site of allergen exposure. Athsma - ANSWERPrimary - vasodilation, vascular leakage, and smooth muscle contraction.
Secondary - infiltration of tissues with eosinophils and other acute and chronic inflammatory cells, as well as tissue damage.
- use a bronchodilator (inhaler) Allergic rhinitis - ANSWER- Most common: 20-40% affected
- confirmed by specific IgE antibodies and/or by a skin prick test
- (runny nose), sneezing, nasal obstruction, nasal itching, and watery eyes Treatment: Antihistamines Intranasal corticosteroids Anaphylaxis - ANSWER- Severe IgE-mediated hypersensitivity reaction
- wide spread release of histamine that produces vasodilation, hypotension, arterial hypoxia, and airway edema.
- level of severity depends on the preexisting degree of sensitization and not with the quantity of exposure Anaphylaxis Grades - ANSWERGrade I - reactions occur in the cutaneous and mucosal tissues with erythema and urticaria, with or without angioedema. Grade II - hypotension, tachycardia, dyspnea, and GI manifestations such as nausea, vomiting, diarrhea, and abdominal cramping from mucosal edema.
Peripheral tolerance - is the suppression of autoreactive lymphocytes in peripheral tissues that have escaped destruction in the thymus. What is autoreactivity? - ANSWERdescribes an organism acting against its own tissue
- cells prone to autoreactivity are typically destroyed during T and B cell development. The goal is to make B and T lymphocytes that are immunologically unresponsive in the presence of self-antigens. MCHs help in this. What is anergy? - ANSWERAnergy is the state of immunologic tolerance to specific antigens. (Anergy creates tolerance to self-antigens and prevents the immune system from self-destruction.) 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. What are autoantibodies? - ANSWER- Occurs in autoimmune diseases
- the immune system loses its ability to recognize self and produces autoantibodies that act against the host. Ex. - Graves disease is autoantibody-induced hyperactivity of the TSH receptor that causes hyperthyroidism.
What are positive and negative selection? - ANSWERPositive selection - when maturing T cells in the thymus display no reactivity to the host MHC antigens and are allowed to mature. Negative selection - T cells that have a high affinity for self-antigens are sorted out and undergo apoptosis. What are the 2 general causes of autoimmune diseases? - ANSWERgenetic and environmental factors Susceptibility genes - ANSWERGenes often associated with disease development. They don't mean you will have an autoimmune disease. A trigger event may be a virus or other microorganism, a chemical substance, or a self-antigen from a body tissue that was previously hidden may lead to development. How do you diagnose an autoimmune disease? - ANSWERDiagnosis is made by history, physical, and serological findings. Need:
- evidence of an autoimmune reaction
- the immunologic findings are not secondary to another condition
- no other identifiable causes are found
fatigue, muscle aches, night sweats, GI problems, maculopapular rash, and headache.
- HIV attacks CD4+ cells so there is a decrease in the CD4+ T-cell count.
- S and S manifest one-month post-HIV exposure What is the latent phase of HIV infection? - ANSWERThe latent phase is characterized by few signs or symptoms of illness.
- 10 - year duration when CD4+ T-cell count slowly falls from the normal range of 800-1000 cells/μL to 200 cells/μL or lower. What is the last phase of HIV infection? - ANSWERThe last phase, or AIDS illness, occurs when the CD4+ cell count falls to less than 200 cells/μL or exhibits an AIDS-defining illness.
- 60 - 70% of HIV-infected people develop AIDS within 10-11 years post- infection
- If CD4+ T cells fall below 200 cells/μL, death occurs within 2 - 3 years. What are opportunistic infections? - ANSWEROpportunistic infections occur more often or are more severe in people with weakened immune systems. They are Viral, bacterial, fungal, and protozoan.
Describe the different diagnostic methods for HIV. - ANSWEREnzyme immunoassay (EIA) or enzyme-linked immunosorbent assay (ELISA) - The best diagnostic method to detect HIV is these HIV antibody tests. Western Blot assay - detect the presence of antibodies to specific viral antigens with a higher degree of specificity and sensitivity. done to confirm EIA positive results. This is because the EIA has a high false- positive result. Polymerase chain reaction (PCR) - is used to amplify and detect the presence of trace amounts of viral DNA in infected cells. Used to test infants born to infected mothers because these infants would have their mother's antibodies regardless is they are infected. Highly active antiretroviral therapy (HAART) - ANSWERCombination of three (or four) antiviral agents often targeting entry/fusion events, reverse transcriptase, integrase, and protease enzymes. What are the cardinal signs of inflammation? - ANSWERRubor - 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? - ANSWERVascular Phase - causes changes in the arterioles, capillaries, and venules at the site of injury.
WBC counts:
- Bacterial infection cause _________________ to increase.
- Parasitic infections and allergic responses cause ________________ to increase.
- Viral infections tend to decrease ___________ and increase _____________. - ANSWER- Bacterial infections cause the neutrophil counts to increase.
- Parasitic infections and allergic responses cause an increase in eosinophils.
- Viral infections tend to decrease the neutrophils and increase the lymphocytes. What are the 3 stages of wound repair? - ANSWER(1) the inflammatory phase
- begins at the time of injury with the formation of a blood clot and migration of phagocytic WBCs into the wound site (2) the proliferative phase - build new tissue to fill the wound space with fibroblasts. (3) the wound contraction and remodeling phase - begin about 3 weeks after injury when a fibrous scar develops. Primary or secondary intention - ANSWERPrimary Intention - A sutured surgical incision Secondary Intention - Larger wounds, like burns, have a greater loss of tissue and contamination and heal slower and results in larger amounts of scar tissue.
Keloid - ANSWERtumor-like masses caused by excess production of scar tissue What factors can inhibit wound repair? - ANSWERFactors 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.
