OPT2222 Exam 1 Flashcards
(131 cards)
1
Q
How do you control microorganisms?
A
Disinfectants
Antiseptics
Sterilization
Hand Washing (Sanitization and Degermination)
2
Q
What is sepsis?
A
State of putrefaction or decay
3
Q
What is the application of agents onto body surfaces (skin, conjunctiva) to destroy or slow growing microorganisms?
A
Antiseptics
pH balanced and isotonic
4
Q
What is the application of agents onto inanimate surfaces (counters, instruments) to destroy or slow growing microorganisms?
A
Disinfectants
5
Q
What is the complete removal and destruction of all microorganisms on an inanimate surface?
A
Sterilization
6
Q
What microorganisms have the highest microbial resistance?
A
Nonliving prions
Dormant Bacterial endospores
[things you can’t kill since they aren’t alive]
7
Q
What microorganisms have moderate microbial resistance?
A
Pseudomonas Mycobacterium Tuberculosis (b/c of waxy coat) Staphylococcus Aureus (most plentiful microbe on body) Protozoan Cysts (can fight destruction)
8
Q
What microorganisms have the least microbial resistance?
A
Bacterial vegetative cells
Fungal spores, hyphae, yeast
Enveloped Viruses
Protozoan Trophozoites
9
Q
What is microbial death?
A
Permanent loss of reproductive capability
hard to detect even under optimal growth conditions
10
Q
What are the 9 factors that influence death rate of microorganisms?
A
Number of microbes Nature of microbes Temperature pH Concentration of agent Mode of action of agent Presence of solvents Organic Matter Inhibitors
11
Q
What is the anitmicrobial mode of action of drugs, detergents and alcohol?
A
Cell wall becomes fragile and cell lyses
remember….eukaryotic cells don’t have a cell wall
12
Q
What is the anitmicrobial mode of action of detergent surfactants?
A
Cell membrane loses integrity (surface wall breaks up)
13
Q
What is the anitmicrobial mode of action of cholramphenicol, ultraviolet radiation and formaldehyde?
A
Prevention of replication, transcription, translation and protein synthesis
14
Q
What is the anitmicrobial mode of action of heat?
A
Disrupt or denature proteins
15
Q
What is the shortest time to kill all microbes at a specific temperature?
A
Thermal Death Time (TDT)
16
Q
What is the lowest temperature required to kill all microbes in 10 minutes?
A
Thermal Death Point (TDP)
17
Q
What is moist heat sterilization?
A
Steam under pressure
Autoclave
Steam must reach surface of item being sterilized
Item must not be heat, pressure or moisture sensitive
18
Q
What are the requirements for autoclaving?
A
15 psi
121 degrees Celsius
10-40 minutes
19
Q
What method can be used for intermittent sterilization when substances cannot withstand autoclaving?
A
Tyndallization (nonpressurized application of steam)
not effective in medicine
20
Q
What is tyndallization used for?
A
canned foods and laboratory media
21
Q
What is deep penetrating energy that causes electrons to leave their orbit (breaks/damages DNA)?
A
Ionizing Radiation (gamma, x-rays, cathode ray)
22
Q
How many levels of chemical decontamination and what are they?
A
3 levels:
High-level germicides
Intermediate level
Low-level
23
Q
What do high level germicides do and what are they used for?
A
They kill endospores (sterilants) and are used in sterile environments (body tissue).
They are usually toxic.
24
Q
What do intermediate level germicides do and what are they used for?
A
They kill fungal spores, tubercle bacillus and viruses. They are used to disinfect devices in contact with mucous membranes.
25
What do low level germicides do and what are they used for?
They eliminate vegetative bacteria, vegetative fungal cells and sensitive viruses. They are used to clean surfaces that touch skin.
26
How do halogens work?
Denature proteins by disrupting disulfide bonds
27
How do surfactants work?
Dissolve membrane lipids and coagulating proteins of vegetative bacterial cells and fungi
28
Nosocomial or HAI
hospital or health care center acquired infection
29
Zoonosis
animal acquired infection in a human
30
hypopyon
accumulation of pus in anterior chamber of eye
31
What does the Greek word pathos mean?
Feeling, suffering
32
What does the Greek word logia mean?
The study of
33
What does pathology mean?
The study of disease
34
What are the top 5 causes of Blindness in the US?
1. Age-related macular degeneration
2. Cataracts (top cause worldwide)
3. Diabetic retinopathy
4. Glaucoma
5. Corneal opacification
35
How many people get regular eye exams?
21% of population
36
What is the most common differential diagnosis made?
Diagnosis of the Red Eye
37
What are Cataracts?
A clouding of the natural lens of the eye
| Only solution is surgery
38
What is involved in cataract surgery?
Microincision
Phacoemulsification - ultrasonic, breaks up cataract and removes through same tool
Femtosecond Laser Surgery - makes incision and breaks up cataract, removal and insertion of IOL still done mechanically
Removal of clouded lens
Insertion of IOL
39
What are the goals of microsurgery of the eye?
Improve vision for the visually impaired
| Restore vision for those who cannot see
40
What is glaucoma?
An increase in the eye pressure (normal is 18-20 mmHg) that damages the optic nerve.
Though pressure is not the only cause and is not always directly related to damage)
41
How many people are affected by glaucoma?
67 million worldwide
3 million in US
1 out of 40 are unaware have it (happens gradually, painless)
African Americans are 4X as common and 10X as likely to go blind.
42
What do you lose first with glaucoma?
peripheral vision
43
How is glaucoma diagnosed?
Measure eye pressure
Image the Optic nerve
Optical Coherence Tomography (OCT)
Measure Visual Field
44
What are the diseases of the Retina?
Age-related macular degeneration (ARMD)
| Diabetic retinopathy
45
What does the Greek word pharmakon mean?
Poison or Drug
46
What is pharmacology?
The study of drugs or medicinals
47
How are ocular drugs administered?
Topical
Oral - very difficult
Injection under or into eye
Intravenous
48
What are Water mixtures?
Substances that are physically but not chemically combined
49
Water comprises how much of body weight?
50-75%
| The eye is mostly water.
50
What is solvency?
The ability to dissolve chemicals
51
Do hydrophobic or hydrophilic substances dissolve in water?
Hydrophilic (charged substances) dissolve in water.
| Hydrophobic (neutral substances) dissolve in oil.
52
What are the different types of drugs?
```
Solutions
Suspensions
Colloids
Emulsions
Ointments
Creams
```
53
What is a Solution?
A mixture of solute in solvent.
Small particles easily pass through cell membranes
Transparent
Remains mixed
54
What is a Colloid?
A mixture of protein and water.
Particles are too large to pass through cell membranes
Cloudy
55
What is a Suspension?
```
Particles suspended in solvent
Too large to pass through a cell membrane
Opaque
Separates on standing
Steroid in water
```
56
What is an Emulsion?
Suspension of one liquid in another
| Example: oil in water (salad dressing)
57
What are Universal Precautions?
Handling everything with the assumption that it is contaminated/lethal
58
What is the first line of defense to fighting pathogens?
Disinfect the External Barrier (skin)
| Wash hands!
59
What are the 3 elements of disease transmission?
1. A source or reservoir of infectious agent
2. A susceptible hostwith a portal of entry for the agent
3. A mode of transmission (You!)
60
How can diseases be transmitted?
Direct Contact - 1 person to another
| Indirect Contact - through a contaminated object (fomite)
61
What is the easiest way to infect an eye?
1. Direct Contact (person to person)
2. Indirect Contact (fomite)
3. Person infects themselves (most common)
62
Methods for Studying Microbes
Staining
| Culturing
63
What are the 5 I's of culturing microbes?
Inoculation - introduction of a sample into a container of media to produce a culture of observable growth
Incubation - conditions that allow growth
Isolation - separating one species from another
Inspection - looking at characteristics
Identification
64
What is a colony?
a mass of the same bacterial cell type
65
What are the techniques for Isolation?
Streaking
Pouring
Spreading
66
What is unique about ophthalmic cultures?
Sample must be obtained directly from patient (only take cells from area in question so as not to get other microbes on lashes, etc.)
Must be plated and cultured immediately
67
What is the most common nutrient media?
Nutrient broth - liquid medium containing beef extract and peptone
68
What types of cultures can be seen in Inspection phase (look and observe)?
Pure culture - grows only a single known species
Mixed culture - holds two or more identified species
Contaminated culture - grows unwanted microbes
69
How do you dispose of cultures?
Incineration or Steam sterilization
70
What type of image does the objective lens create?
Magnified real image
71
What type of image does the oculars create?
Virtual image you see
72
What is the total magnification of a microscope?
Power of the Objective lens x Power of Ocular
73
What is Resolving Power?
Resolution - the capability to distinguish between two adjacent objects
74
What is resolving power a function of?
The wavelength of light and the characteristics of the objective lens (if wavelength of object looking at is smaller than the wavelength of light, can't see with light microscope!)
75
What is the numerical aperture of lens?
Ranges from 0.1 to 1.25
| Increases depth of focus, but decreases amount of light coming in so can't see as well
76
What does Oil immersion prevent and what is it used for?
Prevents Refractive loss of light resolution
| Used for higher magnifiation 40X to 2000X
77
Applying optical lens directly to the eye with a coupling fluid (like an oil immersion lens on a microscope) is what?
Gonioscopy
78
What is the most common stain?
H and E
| Hematoxylin (blue) and Eosin (red)
79
Basic Staining characteristics
Cationic + Chromophore (colored molecule)
Positive staining
Surfaces of microbes negatively charged attract basic dyes
Blue
80
Acidic Staining characteristics
Anionic + chromophore
Negative staining
Microbe repels dye and background is stained
Red
81
Using one dye that reveals shape, size and arrangement of cells is called?
Simple stain
82
Using a primary stain and a counterstain that distinguishes cell types or parts is called? Give examples
Differential stain
Gram stain (+ = blue and - = red, - bacteria are usu. in gut)
Acid-fast stain (for dense, waxy, capsulated bacteria)
Endospore stain (anthrax)
83
What are the 4 basic steps of a Gram stain?
Primary stain - Crystal Violet
Trapping agent - Gram's iodine
Decolorization - Alcohol or acetone
Counterstain - Safranin
84
What is an infection?
When pathogenic microbes penetrate host defenses, enter tissues, and multiply
85
What are established resident microbes that the body harbors in areas that contact the outside environment?
Resident Flora
86
What is ophthalmia neonatorum
an STD transmitted from mother to baby's ocular conjunctiva and cornea (through vaginal delivery)
87
What benefits the host by preventing overgrowth of harmful microbes (antagonism)?
Normal resident flora
88
What occurs when normal flora get into a microbe-free area such as the inside of the eye?
Endogenous Infection (endophthalmitis - intraocular infection)
89
What are the 2 cutaneous populations of flora on the skin?
Transients - Influenced by hygiene
| Resident - Stable and predictable
90
Body has how many cells?
10 to the 13th (most microbes in skin are gram + cocci)
91
Gastrointestinal tract has how many microbes in colon?
10 to the 14th (10X as many cells in our body)
92
What causes disease in healthy persons with normal immune defenses?
True pathogen
93
How do you restore normal resident flora?
Probiotics - return good microbes back to body
| Appendix stores all intestinal bacteria so can replenish if needed
94
What causes disease when the host's defenses are compromised?
Opportunistic pathogens
95
What is the minimum number of microbes required for infection called?
Infectioous Dose (ID)
96
How do pathogens attach to their host?
Adhesion
97
What are toxic to white blood cells?
Leukocidins
98
What dissolves extracellular barriers and penetrate cells?
Exoenzymes
99
What pathogens has strong specificity for a target cell?
Exotoxins
100
What are A-B Toxins?
Hemolysins
101
What releases LPS as part of the outer membrane of Gram - cell walls?
Endotoxins
102
What are the 4 stages of clinical infection?
Incubation
Prodrome
Invasion
Convalescence
103
What is the time from initial contact with a pathogen to appearance of symptoms?
Incubation and Prodrome
104
In what stage of clinical infection does the agent multiply but damage is insufficient to cause symptoms?
Incubation and Prodrome
105
In what clinical infection stage does the microbe multiply to high levels, become established and begin showing more specific signs and symptoms?
Invasion
106
In what clinical infection stage does the patient begin to defeat the infection, symptoms lessen, vision improves, and redness, swelling and discharge reduce?
Convalescence
107
What type of infection remains confined strictly to the specific tissue or area infected?
Localized infection
108
What is a localized infectious agent inoculated into the conjunctiva and causes disease elsewhere in the body?
Focal infection
109
What infection spreads through the bloodstream to other tissues and organs?
Systemic infection
110
What are the 5 cardinal signs of inflammation?
1. Tumor - swelling
2. Rubor - redness
3. Calor - heat
4. Dolor - pain
5. Functio laesa - loss of function
111
What occurs when microorganisms multiply and travel in the bloodstream?
Septicemia
112
What is it called when there are small numbers of bacteria present in the blood (not necs. causing disease)?
Bacteremia
113
What is it called when there are small numbers of viruses present in the blood?
Viremia
114
What would you call an individual infected with a microbe but showing no signs of infection?
Asymptomatic
115
What is a person, symptomatic or not, that spreads infection to others?
A Carrier
| A Reservoir of infection
116
Soil, water and air are what type of reservoir?
Nonliving reservoirs
117
When an infected host infects another with a communicable disease
contagious
118
What are the modes of transmission for infection?
Direct - physical contact
| Indirect - from infected host to an intermediate then to another host (fomite)
119
What are the most common causes of nosocomial infections?
E. coli (gut)
Pseudomonas (wet areas, water)
Staphylococcus (skin)
2-4 million cases/yr 90,000 deaths
120
Why practice universal precautions?
to prevent the spread of infections
121
What is the study of the frequency and distribution of disease?
Epidemiology
122
What is collecting, analyzing and reporting data on rates or occurrence called?
Surveillance
123
What is the number of people in a population that have died?
Mortality
124
What is the number of people in a population with disease?
Morbidity
125
What is the principal government agency responsible for keeping track of infectious disease nationwide?
Centers for Disease Control (CDC) in Atlanta, GA
126
What is morbidity with a steady frequency over time in a particular locale?
Endemic
127
What is morbidity with occasional cases at irregular intervals?
Sporadic
128
What is morbidity with increasing prevalence of a disease beyond expectations?
Epidemic
129
What ocular disease always leads to an epidemic if source is not controlled with quarantine?
Infectious Pink Eye or Epidemic Keratoconjunctivitis (EKC)
130
What culture media absorbs oxygen, slows penetration of oxygen into medium, and is used for growing anaerobic bacteria?
Reducing media
131
What is the purpose of inflammation?
Limits spread and destroys pathogens
Removes cellular debris
Initiates tissue repair
