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253 Cards in this Set
- Front
- Back
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Define normal resident flora.
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Also called indigenous flora or microbiota, it is microbes that engage in mutual or commensal associations residing in or on the human body.
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What is a pathogen?
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An infectious agent
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Define infection.
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The entry, establishment and multiplication of pathogenic organisms within a host. The host, however, is asymptomatic or just a carrier.
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Define infectious disease.
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That state of damage or toxicity in the body caused by an infectious agent. Showing symptoms, damage to tissues or organs.
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What is microbial antagonism?
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The overgrowth of harmful microbes. Indigenous flora benefit the host by preventing this.
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What is an endogenous infection?
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It occurs when normal flora is introduced to a site that was previously sterile. An example is when a newborn's digestive tract is colonized when nursing from his mother.
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What part of the skin is covered by flora?
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- The epidermis
- sebaceous (oil) glands - sweat glands - hair follicles and roots. |
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What are the two cutaneous populations of the skin?
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The transients, which are influenced by hygiene and the residents, which are stable, predictable and less influenced by hygiene.
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Name the normal flora of the skin.
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Staphylococcus, streptococcus and micrococcus.
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Where is the most unique and diverse flora of the body?
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The mouth.
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What is the bacterial count of saliva?
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5 x 10^9 per milliliter
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How many microbes are there per gram of feces?
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10^8 - 10^11 per gram
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What kind of bacteria favors the intestinal environment?
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Anaerobic
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What kind of bacteria live in the intestines and what do they contribute to?
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E. coli, staphylococci, streptococci contribute to intestinal odor.
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What kind of bacteria live in the nasopharynx?
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Neisseria
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What kind of bacteria live in the tonsils and lower pharynx?
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Haemophilus
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What kind of bacteria live in the mouth?
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Streptococci
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What kind of bacteria colonize the nasal entrance, nasal vestibule and the ANTERIOR nasopharynx?
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Staph aureus and strep
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What are the sites that harbor microflora in the female genitourinary tract of females?
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The vagina and the outer opening of the urethra.
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What are the sites that harbor microflora in the genitourinary tract of males?
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Anterior urethra
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What affects the changes in physiology that influence the composition of the normal flora of the vagina?
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Estrogen, glycogen & pH
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What may alter normal flora?
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Antibiotics, dietary changes, and disease.
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What are the factors that weaken host defenses and increase susceptibility to infection?
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Old age and extreme youth
genetic or acquired defects in immunity surgery and organ transplants Organic disease: Cancer, liver malfunction, diabetes chemotherapy/ immunosuppressive drugs physical or mental stress other infections |
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What are true pathogens?
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Pathogens capable of causing disease in healthy persons with normal immune defenses
Examples include Influenza virus, plague bacillus, malarial protozoan |
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What are opportunistic pathogens?
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Microbes that cause disease when the host’s defenses are compromised or when they grow in part of the body that is not natural to them.
Examples are Pseudomonas sp & Candida albicans |
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What is a virulence factor?
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A characteristic or structure that contributes to the ability of a microbe to cause disease.
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What is a portal of entry?
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The characteristic route a microbe follows to enter the tissues of the body.
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What are the 6 portals of entry into the body?
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1. Skin – incisions,
2. G.I. - ingesting 3. respiratory 4. Urinary tract 5. Reproductive tract (STIs) 6. Transplacental |
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What is an exogenous agent?
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An agent from outside the body
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What is an endogenous agent?
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Normal Flora
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What is an infectious dose (ID)?
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Minimum number of microbes required for infection to proceed.
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Does the ID of an infection affect it's virulence?
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Yes, microbes with smaller IDs have a greater virulence.
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How do microbes gain a stable foothold at the portal of entry?
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Adhesion.
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What are the 7 ways for microbes to gain adhesion?
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1. fimbriae
2. cilia (protozoa) 3. flagella 4. slime layers 5.suckers 6. barbs - helminthes 7. hookes |
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What is the Initial response of host defenses?
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Phagocytosis.
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What are the factors called that is used by microbes to avoid the initial response of the host defense?
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Antiphagocytic factors.
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What are some antiphagocytic factors?
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1. capsule
2. slime layers - biofilms 3. enzymes 4. toxins |
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What is a potent source of cellular damage?
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Bacterial toxins.
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Name the two bacterial toxins.
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Endotoxins and exotoxins.
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What are endotoxins?
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A toxin that is not secreted but is released after the cell is damaged. It is composed of lipopolysaccharides, part of the outer membrane of gram negative cell walls.
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What are exotoxins?
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A toxin molecule secreted by a living bacterial cell into the infected tissue.
Strong specificity for a target cell – small quantities |
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What are the 4 stages of infection and disease?
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Incubation period
prodromal stage period of invasion convalescent period |
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Describe the incubation period.
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Time from initial contact with the infectious agent to the appearance of first symptoms; agent is multiplying but damage is insufficient to cause symptoms; several hours to several years.
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Describe the prodromal stage.
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There are vague symptoms, malaise.
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Describe the period of invasion.
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Illness. Sick with the symptoms specific to the illness.
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Describe the convalescent period.
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Symptoms are declining. Death phase.
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What are the patterns of infection?
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Localized infection
Systemic infection Focal infection Mixed infection Primary Infection Secondary Infection |
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What is a localized infection?
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Microbes enter the body and remains confined to a specific tissue.
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What is a systemic infection?
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Infection spreads to several sites and tissue fluids usually in the bloodstream – sepsis, septic.
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What is a focal infection?
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When infectious agent breaks loose from a local infection and is carried to other tissues – heart from gingivitis
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What is a mixed infection?
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Several microbes grow simultaneously at the infection site - polymicrobial
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What is a primary infection?
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The initial infection.
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What is a secondary infection?
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Another infection by a different microbe
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What is an acute infection?
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An infection that comes on rapidly, with severe but short-lived effects.
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What is a chronic infection?
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An infection that progresses and persists over a long period of time.
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What are the signs versus symptoms of inflammation?
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Earliest symptoms of disease as a result of the activation of the body defenses - somewhat subjective (pain, soreness, fever, swelling) Vs. signs of inflammation - Edema – accumulation of fluid
Granulomas and abscesses – walled-off collections of inflammatory cells and microbes Lymphadenitis – swollen lymph nodes |
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What is an asymptomatic infection?
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Although infected, the host doesn’t show any signs of disease
Inapparent infection, so person doesn’t seek medical attention |
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What is a portal of exit and what does it influence?
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Pathogens depart by a specific avenue; greatly influences the dissemination of infection – how it spreads
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Name of the portals of exit.
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Respiratory – mucus, sputum, nasal drainage, saliva
Skin scales Fecal exit Urogenital tract Removal of blood |
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What is latency?
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After the initial symptoms in certain chronic diseases, the microbe can periodically become active and produce a recurrent disease; person may or may not shed it during the latent stage.
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What is a chronic carrier?
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A person with a latent infection who sheds the infectious agent.
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What is sequelae?
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Long-term or permanent damage to tissues or organs.
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What is a reservoir?
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A primary habitat of pathogen in the natural world
Ex. Human or animal carrier, soil, water, plants |
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What is a source?
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An individual or object from which an infection is actually acquired.
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What is a carrier?
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An individual who inconspicuously shelters a pathogen and spreads it to others; may or may not have experienced disease due to the microbe. An asymptomatic carrier shows no symptoms.
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What is a passive carrier?
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An example would be a contaminated healthcare provider picks up pathogens and transfers them to other patients.
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What is a Communicable disease?
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when an infected host can transmit the infectious agent to another host and establish infection in that host.
A highly communicable disease is contagious. |
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What is a Non-communicable infectious disease?
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A disease that does not arise through transmission from host to host. Occurs primarily when a compromised person is invaded by his or her own normal microflora. Contact with organism in natural, non-living reservoir
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What are patterns of transmission?
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Direct contact or indirect contact via a vehicle or airborne
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What is considered direct contact?
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Physical contact or fine aerosol droplets.
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What is considered indirect contact?
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It passes from infected host to intermediate conveyor and then to another host (airborne) - a vehicle.
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What is a vehicle?
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Inanimate material, food, water, biological products, fomites (inanimate objects)
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What is a nosocomial infection?
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One acquired in the hospital or developed during a hospital stay.
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Define Epidemiology.
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The study of the frequency and distribution of disease and health-related factors in human populations.
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Define prevalence.
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The total cumulative number of cases of a disease in a certain area and time period.
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Define Incidence.
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The number of new cases of a disease occurring during a period.
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Define Mortality Rate.
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The total number of deaths in a population attributable to a particular disease.
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Define Morbidity rate.
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The relative incidence of a disease in a community.
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What is endemic?
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A native disease that prevails continuously in a geographic region.
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What is a sporadic disease?
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A disease that exhibits new at irregular intervals in unpredictable geographic locales.
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What is epidemic?
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A sudden and simultaneous outbreak or increase in the number of cases of disease in a community .
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What is pandemic?
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A disease afflicting an increased proportion of the population over a wide geographic area (often worldwide).
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What are innate, natural defenses?
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Immunity present at birth that provide nonspecific resistance to infection.
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What is the first line of defense?
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Any barrier that blocks invasion at the portal of entry – nonspecific.
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What is the second line of defense?
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Protective cells and fluids; inflammation and phagocytosis – nonspecific.
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What are adaptive immunities?
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They are immunities specific to the disease that must be acquired.
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What is the third line of defense?
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Immunities acquired with exposure to foreign substance; produces protective antibodies and creates memory cells – specific
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Give some examples of first line of defense.
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Skin and mucous membranes of respiratory, urogenital, eyes, and digestive tracts.
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Name the nonspecific chemical defenses.
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Sebaceous secretions
Lysozyme, an enzyme that hydrolyzes the cell wall of bacteria, in tears High lactic acid and electrolyte concentration in sweat Skin’s acidic pH Hydrochloric acid in stomach Digestive juices and bile of intestines Semen contains an antimicrobial chemical Vagina has acidic pH |
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What are genetic defenses?
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Some hosts are genetically immune to the diseases of other hosts. Some pathogens have great specificity. Some genetic differences exist in susceptibility.
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What is immunology?
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The study of the body’s second and third lines of defense.
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What are the functions of a healthy functioning immune system?
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1. Surveillance of the body
2. Recognition of foreign material 3. Destruction of entities deemed to be foreign |
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What are the Four major subdivisions of immune system?
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1. Reticuloendothelial system (RES)
2. Extracellular fluid (ECF) 3. Bloodstream 4. Lymphatic system |
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What is the reticuloendothelial system?
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Network of connective tissue fibers that interconnects other cells and meshes with the connective tissue network surrounding organs.
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What inhabits the reticuloendothelial system?
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Phagocytic cells – mononuclear phagocyte system – macrophages ready to attack and ingest microbes that passed the first line of defense
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What is Hemopoiesis?
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production of blood cells
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What are Stem cells?
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undifferentiated cells, precursor of new blood cells
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What are leukoycytes?
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White blood cells. Granulocytes with lobed nucleus and agranulocytes with a round nucleus.
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Name the three kinds of granulocytes.
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Neutrophils, eosinophils and basophils.
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Name the two agranulocytes.
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Lymphocytes (B & T cells) and monocytes (macrophages and dendritic cells).
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What are erythrocytes?
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Red blood cells developed from bone marrow stem cells, lose nucleus, simple biconcave sacs of hemoglobin
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What are platelets?
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Formed elements in circulating blood that are not whole cells.
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What does the lymphatic system do?
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1. Provides an auxiliary route for return of extracellular fluid to the circulatory system
2. Acts as a drain-off system for the inflammatory response 3. Renders surveillance, recognition, and protection against foreign material |
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What is lymphatic fluid?
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Plasma-like liquid carried by lymphatic circulation, made up of water, dissolved salts and 2-5% protein. It transports WBCs, fats, cellular debris and infectious agents. It is formed when blood components move out of blood vessels into extracellular spaces.
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Lymphatic capillaries permeate all body parts except...
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CNS, bone, placenta & thymus.
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How is extracellular fluid move through the body?
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It permeates the thin walls of the lymphatic capillaries which is then moved through by skeletal muscle contraction.
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Lymphatic vessels - one or two way direction?
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One directional - towards the heart.
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Name the primary lymphoid organs.
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The sites of lymphocytic origin and maturation – thymus and bone marrow.
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Name the Secondary lymphoid organs and tissues.
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The circulatory-based locations such as spleen and lymph nodes; collections of cells distributed throughout body tissues – skin and mucous membranes.
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What is the thymus and where is it located?
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The site of T-cell maturation. It has a high rate of growth and activity until puberty, then begins to shrink. It is located above the heart.
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What are lymph nodes?
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Small, encapsulated, bean-shaped organs stationed along lymphatic channels and large blood vessels of the thoracic and abdominal cavities.
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What is the spleen?
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A structure similar to the lymph node; filters circulating blood to remove worn out RBCs and pathogens.
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Name another lymphatic "patch" and where is it located?
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Peyer's patch.
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What are the actions of the second line of defense?
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1. Recognition
2. Inflammation 3. Phagocytosis 4. Interferon 5. Complement |
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What is the inflammatory response?
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Classic signs and symptoms characterized by redness, warmth, swelling and pain.
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What is diapedesis?
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migration of cells out of blood vessels into the tissues
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What is chemotaxis?
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migration in response to specific chemicals at the site of injury or infection
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What is a fever?
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Initiated by circulating pyrogens which reset the hypothalamus to increase body temperature; signals muscles to increase heat production and vasoconstriction
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What are the two pyrogens called?
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Exogenous pyrogens – products of infectious agents and
Endogenous pyrogens – liberated by monocytes, neutrophils, and macrophages during phagocytosis; examples: interleukin |
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What are the benefits of a fever?
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1. Inhibits multiplication of temperature-sensitive microorganisms
2. Impedes nutrition of bacteria by reducing the available iron 3. Increases metabolism and stimulates immune reactions and protective physiological processes |
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What are the General activities of phagocytes?
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1. To survey tissue compartments and discover microbes, particulate matter, and dead or injured cells
2. To ingest and eliminate these materials 3. To extract immunogenic information from foreign matter |
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How do neutrophils work?
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They are general-purpose; react early to bacteria and other foreign materials, and to damaged tissue.
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How do eosinophils work?
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They are attracted to sites of parasitic infections and antigen-antibody reactions.
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How do macrophages work?
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They are derived from monocytes; scavenge and process foreign substances to prepare them for reactions with B and T lymphocytes.
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How are foreign cells recognized?
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Protein receptors within cell membrane of macrophages
detect foreign molecules and signal the macrophage to produce chemicals to stimulate an immune response. |
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What are interferons and what do they do?
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They are small proteins produced by certain WBCs and tissue cells. They are produced in response to viruses, RNA, immune products, and various antigens, they bind to cell surfaces and induce expression of antiviral proteins and inhibit expression of cancer genes.
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What are complement proteins?
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Consists of 26 blood proteins that work in concert to destroy bacteria and viruses. They are activated by a cascade reaction.
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Define Specific Immunity.
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The adaptive, or third line of defense. It is acquired immunity with a dual system of B & T lymphocytes. Immunocompetence.
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What is an antigen?
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Molecules that stimulate a response by T and B cells – cell, particle, chemical.
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What are Two features that characterize specific immunity?
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Specificity and memory.
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Define specificity.
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antibodies that are produced, function only against the antigen that they were produced in response to
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Define memory.
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lymphocytes are programmed to “recall” their first encounter with an antigen and respond rapidly to subsequent encounters
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What is the Major Histocompatibility Complex (MHC)?
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Receptors found on all cells except RBCs. Plays a role in recognition of self by the immune system and in rejection of foreign tissue. Own MHC genes (will give kidney that is closer match)
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Describe lymphocyte receptors?
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Lymphocyte’s role in surveillance and recognition is a function of their receptors.
B-cell receptors – bind free antigens. T-cell receptors – bind processed antigens together with the MHC molecules on the cells that present antigens to them. |
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Where do lymphatic stem cells begin and where do they mature?
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In the bone marrow, lymphocytic stem cells differentiate into either T or B cells. B cells stay in the bone marrow while T cells migrate to the thymus. Both T and B cells migrate to secondary lymphoid tissue.
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What is a clonal selection?
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A selection of genetically distinct lymphocytes. First introduction of each type of antigen into the immune system selects from them. It Causes it to expand into a clone of cells that can react to that antigen (B-cells).
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What is A?
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Light chains.
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What is B?
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Antigen Binding sites.
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What is C?
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Disulfide bonds.
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What is D?
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Heavy Chains.
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What is this a picture of?
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An antibody.
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What are antibodies?
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Immunoglobulins, large glycoproteins that serve as specific receptors of B cells.
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Describe B-cell maturation.
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They are directed by bone marrow sites. Millions of distinct B cells develop and “home” to specific sites in the lymph nodes, spleen, and GALT (gut associated lymphatic tissue).
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Describe T-cell maturation.
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Maturation is directed by the thymus gland and it's hormones. Mature t-cells migrate to the lymphoid organs.
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What is antigenicity?
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A property of behaving as an antigen. How pathogenic it is, it's foreignness, size, shape and accessibility.
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What is an epitope?
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The site on an antigen at which a specific antibody becomes attached.
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What do the lymph nodes and spleen do with antigens?
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Concentrate the antigens and circulate them so they will come into contact with lymphocytes. T & B cells are here.
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How do T-cells find out about antigens?
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Antigens must be processed by phagocytes called antigen presenting cells (APC), which modify the antigen, move it to the APC surface and bind it to the MHC receptor.
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What does MHC stand for?
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Major Histocompatability Complex.
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What is the Principle antibody activity ?
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to unite with the Ag, to call attention to, or neutralize the Ag for which it was formed
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What is Opsonization?
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The process of coating microorganisms or other particles with specific antibodies so they are more readily recognized by phagocytes
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What is Neutralization?
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The Abs fill the surface receptors on a virus or the active site on a microbial enzyme to prevent it from attaching.
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What is agglutination?
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Ab aggregation; cross-linking cells or particles into large clumps
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What is Complement fixation?
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Activation of the classical complement pathway can result in the specific rupturing of cells and some viruses.
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What is Precipitation?
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Aggregation of particulate antigen.
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How many classes of immunoglobulins are there and name them.
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IgG - most prevalent- made from plasma & memory cells
IgA - monomer circulates in blood IgM - 5 monomers - 1st class made after Ag encounter IgD - monomer, serves as a receptor for antigen on B-cell IgE - involved in allergic reactions & parasitic worm inf.s |
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What are monomers?
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simple molecules that can be combined to
Make larger molecules |
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Describe immunoglobulin A.
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The predominant immunoglobulin class in saliva, tears, seminal fluid, colostrum, breast milk, muscous secretions of the nose, lungs and gastrointestinal tract.
Protect external openings and mucous membranes from attachment, colonization, and invasion of pathogens. |
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Describe immunoglobulin D.
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Found in large quantities on the surface of B cells. Serve as antigen receptors, so antigens can attach directly to B cells.
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Describe immunoglobulin E.
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Produced in response to allergens. Found on the surface of basophils and mast cells. Found around eyes, Nose, respiratory or GI tract (allergies).
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Describe immunoglobulin G.
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The only class of immunoglobulins that can cross the placenta. High levels are produced within 1-3 days of infection during a secondary response. Long lived and may last a lifetime (not the kind that has crossed the placenta). Most abundant immunoglobulin in blood.
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Describe Immunoglobulin M.
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First antibodies formed in response to antigens. Primary response. Short lived – last Only a few months
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What is a monoclonal antibody?
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An antibody, produced by a single clone of cells grown in culture, that is both pure and specific and is capable of proliferating indefinitely to produce unlimited quantities of identical antibodies: used in diagnosis, therapy, and biotechnology
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Describe the primary response.
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After first exposure to an Ag immune system produces IgM and a gradual increase in Ab titer (concentration of antibodies) with the production of IgG
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Describe the secondary response.
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After second contact with the same Ag, immune system produces a more rapid, stronger response due to memory cells
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What is the Anamnestic response?
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The memory response. Immediate.
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What are superantigens?
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A virulence factor. Provoke overwhelming immune responses by large numbers of T cells
Release of cytokines Ex. Diphtheria Blood vessel damage Toxic shock Multiorgan damage |
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What is active immunity?
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Results when a person is challenged with antigen that stimulates production of antibodies; creates memory, takes time, and is lasting
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What is Passive immunity ?
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Preformed antibodies are donated to an individual; does not create memory, acts immediately, and is short term. Can also be received through breastmilk.
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What is natural immunity?
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Acquired as part of normal life experiences.
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What is Artificial immunity ?
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acquired through a medical procedure such as a vaccine
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What are vaccines prepared from?
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1. Killed whole cells or inactivated viruses
2. Live, attenuated cells or viruses 3. Antigenic molecules derived from bacterial cells or viruses 4. Genetically engineered microbes or microbial agents |
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Describe killed or inactivated vaccines.
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They Cultivate the desired strain, treat it with formalin or some other agent that kills the agent but does not destroy its antigenicity.
It Often requires a larger dose and more boosters to be effective |
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Describe live or attenuated vaccines.
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Attenuated means weakened. Process that substantially lessens or negates the virulence of viruses or bacteria – eliminates virulence factors. Examples include the oral polio vaccine or the flu mist
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What are the advantages of live vaccines?
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- Organisms can multiply and produce infection (but not disease) like the natural organism
- They confer long-lasting protection - Usually require fewer doses and booster |
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What are the disadvantages of live vaccines?
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They Require special storage, can be transmitted to other people, can conceivably mutate back to virulent strain
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Describe antigenic molecule vaccines.
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They are Acellular or subcellular vaccines (subunit – of a virus)
Exact antigenic determinants can be used when known: Capsules – pneumococcus, meningococcus Surface protein – anthrax, hepatitis B Exotoxins – diphtheria, tetanus Antigen can be taken from cultures, produced by genetic engineering, or synthesized |
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What are T helper cells?
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They are the most prevalent type of T cell; regulate immune reaction to antigens, including other T and B cells; also involved in activating macrophages and increasing phagocytosis;
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What are Cytotoxic T cells?
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They destroy foreign or abnormal cells by secreting perforins that lyse cells
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What are Natural killer cells?
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They lack specificity; circulate through the spleen, blood, and lungs
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Describe genetically engineered vaccines.
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Insert genes for pathogen’s antigen into plasmid vector, and clone them in an appropriate host
Stimulated the clone host to synthesize and secrete a protein product (antigen), harvest and purify the protein – hepatitis (naked DNA) |
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What is a trojan horse vaccine?
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genetic material from a pathogen is inserted into a live carrier nonpathogen; the recombinant expresses the foreign genes
Experimental vaccines for AIDS, herpes simplex 2, leprosy, tuberculosis |
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How do genetically engineered vaccines work?
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DNA vaccines create recombination by inserting microbial DNA into plasmid vector
Human cells will pick up the plasmid and express the microbial DNA as proteins causing B and T cells to respond, be sensitized, and form memory cells Experimental vaccines for Lyme disease, hepatitis C, herpes simplex, influenza, tuberculosis, malaria |
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How are vaccines administered?
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Most are administered by injection; few oral, nasal. Some vaccines require adjuvant to enhance immunogenicity and prolong retention of antigen
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What are the risks of being administered a vaccine?
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There is More benefit than risk. Possible side effects include local reaction at injection site, fever, allergies; rarely back-mutation to a virulent strain, neurological effects
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What is "herd immunity"?
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Immune individuals will not harbor it, reducing the occurrence of pathogens – herd immunity
Less likely that a nonimmunized person will encounter the pathogen |
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What is immunopathology?
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The study of disease states associated with underactivity and overactivity of the immune response
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What is Allergy, hypersensitivity?
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an exaggerated, misdirected expression of immune responses to an allergen (antigen)
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What is Autoimmunity?
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abnormal responses to self Ag
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What is Immunodeficiency?
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deficiency or loss of immunity
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What is cancer in relation to immunopathology?
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both a cause and effect of immune dysfunction
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What are the types of Immune System Disorders?
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Type I - Immediate (hay fever, anaphylaxis)
Type II - Antibody mediated (blood type incompatible) Type III - Immune complex (rheumatoid arthritis) Type IV - Cell mediated, cytotoxic (contact dermatitis) |
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Describe Type I Allergic reactions
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Two levels of severity:
Atopy - any chronic local allergy such as hay fever or asthma Anaphylaxis - a systemic, often explosive reaction that involves airway obstruction and circulatory collapse |
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What is the mechanism of a type I allergy?
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After a Provocative dose – subsequent exposure with the same allergen binds to the IgE-mast cell complex
Degranulation releases mediators with physiological effects such as vasodilation and bronchoconstriction |
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What is the role of mast cells in immunology?
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Mast cells are located in the connective tissue of virtually all organs; high concentration in lungs, skin, GI, and genital tract
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What is the role of basophils in immunology?
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Basophils circulate in blood and migrate into tissues
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What are the general targets for allergic symptoms?
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Skin, upper respiratory tract, GI tract, and conjunctiva. Responses include rashes, itching, redness, rhinitis, sneezing, diarrhea and shedding tears
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What are the systemic targets for allergic symptoms?
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smooth muscles, mucous glands, and nervous tissue and responses include vascular dilation and constriction resulting in change in blood pressure and respiration
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What is the main chemical mediator?
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Histamine. It is the must profuse and fast acting, it is a stimulator of smooth muscle, glands and eosinophils
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Acting alone or in combination, what accounts for the scope of allergic symptoms?
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Histamine, serotonin, leukotriene, platelet-activating factor, prostaglandins, bradykinin
(He So Likes Playing Patient Boy) |
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What is Atopic Disease?
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It is seasonal, hay fever, rhinitis, inhaled plant pollen or mold.
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Name two atopic diseases.
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Asthma - severe bronchoconstriction from an inhaled allergen
and eczema - dermatitis from an ingested, inhaled or skin contact with an allergen |
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What is a food allergy and what are the reactions?
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Intestinal portal, can affect skin and respiratory tract. Vomiting, diarrhea, abdominal pain; possibly severe
Eczema, hives, rhinitis, asthma, occasionally anaphylaxis |
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What is a Drug allergy?
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Common side effect of treatment; any tissue can be affected; reaction from mild atopy to fatal anaphylaxis
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What is systemic anaphylaxis?
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Sudden respiratory and circulatory disruption that can be fatal in a few minutes
Allergen and route are variable Bee stings, antibiotics, or serum injection |
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What is the treatment and prevention of allergies?
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Avoiding allergen
Drugs Desensitization therapy |
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What is Desensitization therapy?
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injected allergens may stimulate the formation of high-levels of allergen-specific IgG that act to block IgE; mast cells don’t degranulate
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What is type II hypersensitivity?
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Reactions that lyse foreign cells. Examples include ABO blood groups and the Rh factor, hemolytic disease of the newborn.
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What is hemolytic disease of the newborn?
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An Rh- mother forms antibodies to her Rh+ fetus; usually requires subsequent exposure to the antigen to be hemolytic.
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What is type III hypersensitivity?
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Reaction of soluble antigen with antibody and the deposition of the resulting complexes in basement membranes of epithelial tissues. Immune complexes become trapped in tissues and incite a damaging inflammatory response
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Name examples of type III hypersensitivity.
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Arthus reaction – localized dermal injury due to inflamed blood vessels
Serum sickness – systemic injury initiated by antigen-antibody complexes that circulate in the blood |
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What is type IV hypersensitivity?
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T cell-mediated
Delayed response to Ag involving activation of and damage by T cells |
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Name some examples of type IV hypersensitivity.
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Delayed allergic response – skin response to allergens – tuberculin skin test, contact dermatitis from plants, metals, cosmetics
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What happens with T Cells and Organ Transplantation?
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Graft/transplantation rejection – host may reject graft; graft may reject host
MHC markers of donor tissue (graft) are different; T cells of the recipient recognize foreignness |
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Explain autoimmunity.
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In certain type II & III hypersensitivities, the immune system has lost tolerance to autoantigens and forms autoantibodies and sensitized T cells against them.
Disruption of function can be systemic or organ specific. |
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Give some examples of autoimmune disorders.
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Systemic lupus erythematosus
Rheumatoid arthritis Endocrine autoimmunities Myasthenia gravis Multiple sclerosis |
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What are Immunodeficiency Diseases?
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Components of the immune response system are absent. Deficiencies involve B and T cells, phagocytes, and complement
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What are the 2 general categories of Immunodeficiency Diseases?
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Primary immunodeficiency – congenital; usually genetic errors
Secondary diseases – acquired after birth; caused by natural or artificial agents |
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Describe Primary immunodeficiency.
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Lack of B-cell and/or T cell activity
B cell defect – agammaglobulinemia – patient lacks antibodies T cell defect – thymus is missing or abnormal (DiGeorge syndrome) |
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What is Severe combined immunodeficiency (SCID) ?
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Both limbs of lymphocyte system are missing or defective; no adaptive immune response
(Primary immunodeficiency) |
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Describe Secondary Immunodeficiencies.
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Due to damage after birth
- Caused by: infection, organic disease, chemotherapy, or radiation - AIDS most common – T helper cells are targeted; numerous opportunistic infections and cancers |
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Discuss the immune system and cancer.
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* New growth of abnormal cells
* Tumors may be benign (nonspreading) self-contained; or malignant that spreads from tissue of origin to other sites * Appear to have genetic alterations that disrupt the normal cell division cycle * Possible causes include: errors in mitosis, genetic damage, activation of oncogenes, or retroviruses * Immune surveillance, immune system keeps cancer “in check” |
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List the Eukaryotic groups.
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Fungi, Algae, Protozoa and Helminths
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What are the cytopathic effects (damage) of viruses on host cells?
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Changes in size and shape
Cytoplasmic inclusion bodies Inclusion bodies Cells fuse to form multinucleated cells Cell lysis Alter DNA Transform cells into cancerous cells (mnemonic: Can Chris Identify Carnivorous Cats After Training?) |
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What microbes are considered the most abundant on Earth?
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Viruses.
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Describe the viral envelope.
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They are mostly on animal viruses. They are acquired when virus leaves the host cell. Exposed proteins on the outside of the envelope, called spikes, are essential for attachment of the virus to the host cell.
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Describe the nucleic acids.
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DNA viruses are usually double stranded but may be single stranded can also be circular or linear.
RNA viruses are usually single stranded, may be double stranded. |
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What is a polymerase?
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An enzyme used to catalyze the copying of RNA or DNA.
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What is a replicase?
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An enzyme used to catalyze the copying of RNA.
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What are the Modes of Viral Multiplication?
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Adsorption
Penetration Uncoating Synthesis Assembly Release –budding (exocytosis) (or Lysis) (mnemonic: Any Pics U Send Are Remarkable) |
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What are the varieties of virus penetration and uncoating?
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1. The virus fuses with the host cell membrane and the nucleocapsid enters the cell and uncoats the nucleic acid.
2. The host cell membrane engulfs the virus into a vesicle and the vesicle breaks down with the capsid and envelope, release the nucleic acid. 3. The virus adheres to the receptors on the cell membrane of the host. The virus is engulfed in a vesicle and the nucleic acid is released from the vesicle. |
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How would you categorize HIV? (endemic, epidemic, pandemic, or none of these)
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Pandemic
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Mycobacterium tuberculosis
How would you categorize this disease? (endemic, epidemic, pandemic, or none of these) |
it’s endemic to people with HIV and endemic to many countries, but not the US
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What is a Similar pathogen vaccine?
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This is a live vaccine of an isolated virus that is similar to the pathogen it is designed for. This pathogen does not harm the human immune system, but is similar enough that the human immune system will mistake it for the human virus and attack it.
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What is an Attenuated vaccine?
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This is a live vaccine of a pathogen that is altered in the lab to thrive in different conditions. This will cause it not to thrive in the environment of the human body, therefore, weakening it enough for the human immune system to overcome it. This is like the similar pathogen in that it is a live vaccine.
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What is a killed vaccine?
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This is a vaccine that is not live, but many must be needed for the vaccine. Many are grown in a tissue culture but killed in a way that the shape is maintained. The human immune system can then recognize it if exposed to it in the future.
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What is a toxoid vaccine?
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A toxoid vaccine is created to help the human immune system fight a toxin, not the pathogen itself. This vaccine is unique from all the others for this reason. The toxin is neutralized and second neutralized toxin is added to help boost the response of the immune system.
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What is a subunit vaccine?
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This vaccine is created using genetic engineering. Yeast is given a piece of DNA from a virus and when the DNA is adopted by the yeast and replicated, the new yeast creates a protein coat like the one from the pathogen. When the human immune system encounters the protein coat, it attacks it and thinks it’s the pathogen.
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What is a Naked DNA vaccine?
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This vaccine is the most complicated of all the other vaccines. It also requires genetic engineering but a more complicated procedure. PCR primers are used to make billions of copies of a single gene in a growth medium. Vectors, which can tell cells to make proteins based on it’s own DNA, are used and the virus DNA is combined with the vector’s DNA. This way, any cell that the vector invades will replicate the virus DNA. The vectors are then placed in bacteria to replicate the many DNA required for the vaccine. The bacterial cell walls are then ruptured with detergent to release the DNA and the viral DNA is extracted from the bacterial DNA.
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How is influenza spread?
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Spread by contact with respiratory secretions from an infected person (coughing, sneezing, talking)
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What type of flu virus (A or B) can infect animals too? What kind of animals can it also infect?
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Type A can infect pigs and birds as well as humans.
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What is A?
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A Neuraminidase.
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What is B?
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Hemagglutinin
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How many flu virus types are there?
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There are two type A viruses and one type B virus.
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Which blood type is the only blood type that has antibodies for all the other blood types?
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Type O.
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Describe the type A flu virus.
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Causes moderate to severe illness
Affects all age groups Infects humans and other species (pigs and birds) Associated with annual epidemics and pandemics |
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Describe the type B flu virus.
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Usually milder than Type A
Affects humans only May cause annual epidemics |
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Regarding the flu virus, define "drift".
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Minor change due to constant mutation
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why must the seasonal flu vaccine be updated each year?
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Because of drifts.
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Regarding the flu virus, define "shift".
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Major change with new virus causing human infection.
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What causes shifts in viruses?
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Mutations or reassortments. It is a pandemic potential!!
(Shift happens!) |
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What causes a flu pandemic?
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A new strain of virus.
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What are the three influenza pandemic prerequisites?
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1. A new influenza virus emerges;
2. It infects humans, causing serious illness; and 3. It spreads easily and sustainably among humans. |
