Microbiology Exam 3 Flashcards Preview

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Flashcards in Microbiology Exam 3 Deck (32):
1

Defenses of the body against infection

1. Mechanical defenses
2. Physiological defenses
3. Chemical defenses

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Mechanical defenses

anatomical barriers; Example: Skin, mucous membranes, bony encasements

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Physiological defenses- functional

i. Inflammation
ii. Fever
iii. Phagocytosis- cell ingestion

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Chemical defenses

i. Body secretions
ii. Antibodies (Immunoglobulins-Ig)
iii. Interferon

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Lysozyme

enzyme present in tears that kills bacteria

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Gastric juice

acidic, HCl, pH below 7.0 to protect you digestive system

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Antibodies (Immunoglobulins-Ig)

are specific proteins produced by the body in response to a specific foreign protein

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Interferon

virus-neutralizing substance produced individually

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Immunology

the study of immunity; immunity a highly state of resistant to an infection or disease

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Antigens

these are foreign proteins against which the body forms certain antibodies

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Antibodies

specific proteins produced by the body in response to a specific foreign protein

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Characteristics of antigen

antibody reactions: very specific; true antibodies will have bivalent receptor sites; if incomplete, allergic reaction

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Sterilization

process of completely removing and destroying all life forms and their products (exotoxins, endospores) in or on a substance

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Disinfection

process by which you destroy all pathogenic organisms by physical or chemical means

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Antisepsis

the prevention or inhibition of the growth of microorganisms, without necessarily killing them.

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Methods of Control- Physical

1. Scrubbing-
2. Heat-
3. Cold- refrigeration
4. Ultraviolet (UV) light- bactericidal

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Heat

a. Incineration- burning flaming as a lab technique
b. Dry heat- convection oven
c. Moist heat-

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Moist heat

i. Boiling
ii. Free-flowing steam
iii. Steam under pressure: autoclave 121 degree C is standard temperature of an autoclave; 15lbs is standard amount of pressure. Standard Exposure time 15 minutes; best means of physical of true steralization

19

Methods of Control- Chemical

1. Disinfectants- chemical agents proven to kill pathogens
2. Factors influencing the action of disinfectants
3. Disinfectants suitable for mortuary procedures

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Chemical- Disinfectants-

a. Germicide- killing of germs
b. Bactericide- killing of bacteria
c. Fungicide- killing of fungi (yeast & molds)
d. Viricide- chemical agents that kill viruses
e. Insecticide- agents that kills insects
f. Larvacide- chemical agents that kill larva (nits; head lice)

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Factors influencing the action of disinfectants

a. Nature of the disinfectant
b. Concentration of the disinfectant
c. Nature of the material to be disinfected
d. Number of microorganisms present
e. Kind of microorganisms present
f. Time of exposure to disinfectant
g. Temperature of disinfectant during exposure
h. pH of disinfectant during exposure

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Halogens- salt formers

i. Hypochlorites (bleaches)
1. Ex: NaOCL- household bleach 1:10 dilution; standard external disinfectant per CDC
ii. Iodophors- iodine; Betadine

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Alcohols

i. Ethyl alcohol (ethanol)
ii. Isopropyl alcohol (rubbing alcohol)

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Aldehydes- alcohols deprived of hydrogen

i. Formalin (formaldehyde solution) compare strength using index (index- no. of grams of formaldehyde gas dissolved in 100mL of solution)
ii. Glutaraldehyde- 2% as Cidex

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Phenolic compounds

i. Phenol (carbolic acid) – acidic in pH;
ii. Cresols (Lysol)
iii. Hexachlorophene

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Quaternary ammonium compounds

i. (Examples: Benzalkonium Chloride and Zephrian Chloride)

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Natural (innate) immunity

inborn any immunity in which you are born with upon conception
• Racial- incidence of sickle cell anemia
• Species- distemper non-human
• Individual- interferon

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Naturally Active

having the disease & recovering from it

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Naturally Passive

Colostrum (first mothers milk secereted after birth), breast feeding, placental transfer of antibodies

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Artificially acquired

by shot or immunization

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Artificially Active

vaccines (DPT), toxoids, attenuated strains, live or dead, Microorganisms, extracts (PPD)

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Artificially Passive

Conveyed by artificial means instantaneously through a pre-formed antibody. Last the shortest time - 3-7 days. Examples of these artificial means are: immune serum, antiserum, gamma globulin.