Microbiology Exam 3 Flashcards
Defenses of the body against infection
- Mechanical defenses
- Physiological defenses
- Chemical defenses
Mechanical defenses
anatomical barriers; Example: Skin, mucous membranes, bony encasements
Physiological defenses- functional
i. Inflammation
ii. Fever
iii. Phagocytosis- cell ingestion
Chemical defenses
i. Body secretions
ii. Antibodies (Immunoglobulins-Ig)
iii. Interferon
Lysozyme
enzyme present in tears that kills bacteria
Gastric juice
acidic, HCl, pH below 7.0 to protect you digestive system
Antibodies (Immunoglobulins-Ig)
are specific proteins produced by the body in response to a specific foreign protein
Interferon
virus-neutralizing substance produced individually
Immunology
the study of immunity; immunity a highly state of resistant to an infection or disease
Antigens
these are foreign proteins against which the body forms certain antibodies
Antibodies
specific proteins produced by the body in response to a specific foreign protein
Characteristics of antigen
antibody reactions: very specific; true antibodies will have bivalent receptor sites; if incomplete, allergic reaction
Sterilization
process of completely removing and destroying all life forms and their products (exotoxins, endospores) in or on a substance
Disinfection
process by which you destroy all pathogenic organisms by physical or chemical means
Antisepsis
the prevention or inhibition of the growth of microorganisms, without necessarily killing them.
Methods of Control- Physical
- Scrubbing-
- Heat-
- Cold- refrigeration
- Ultraviolet (UV) light- bactericidal
Heat
a. Incineration- burning flaming as a lab technique
b. Dry heat- convection oven
c. Moist heat-
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
Methods of Control- Chemical
- Disinfectants- chemical agents proven to kill pathogens
- Factors influencing the action of disinfectants
- Disinfectants suitable for mortuary procedures
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)
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
Halogens- salt formers
i. Hypochlorites (bleaches)
1. Ex: NaOCL- household bleach 1:10 dilution; standard external disinfectant per CDC
ii. Iodophors- iodine; Betadine
Alcohols
i. Ethyl alcohol (ethanol)
ii. Isopropyl alcohol (rubbing alcohol)
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
Phenolic compounds
i. Phenol (carbolic acid) – acidic in pH;
ii. Cresols (Lysol)
iii. Hexachlorophene
Quaternary ammonium compounds
i. (Examples: Benzalkonium Chloride and Zephrian Chloride)
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
Naturally Active
having the disease & recovering from it
Naturally Passive
Colostrum (first mothers milk secereted after birth), breast feeding, placental transfer of antibodies
Artificially acquired
by shot or immunization
Artificially Active
vaccines (DPT), toxoids, attenuated strains, live or dead, Microorganisms, extracts (PPD)
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.
