Chapter Three Flashcards
Light source
Shines light on specimen
condenser
Focuses light thru specimen
Ocular lens
(Eye piece)
-remagnifies x10 the image produced by objective lens
Body tube transmits
The image from the objective lens to ocular
Objective lenses
Magnifies the specimen
Stage holds the
Microscopic slide in position
Diaphragm controls the
Amount of light entering the condenser
Illuminator
The light source
Stain
Salts composed of a positive and negative ion
Chromophore of a stain
Coloring agents responsible for colours in a stain
Acidic dye vs basic dye
Acidic dye- anion
Basic dye- cation
Negative staining
Staining background instead of cell
Bacteria is _____ charged, meaning it is never an _____ stain
Negatively, acidic
Bacteria is ALWAYS a ____ stain
Basic
Simple stain determines
Shape, arrangements and size of an organism
Simple stain is a single ___ ____
Basic dye
Does simple staining diagnose? q
No, its basic
Simple stain, intensify original colour (what’s the word for this)
Mordant
Differential stain function
Used for distinguishing and diagnosing between bacteria
Types of differential stains
-gram stain
-acid fast stain
What does the gram stain discover/how long is the procedure
Bacteria is either gram positive or negative
-multi step procedure (5 min)
Primary step of gram stain
Using crystal violet
-purple +
-purple -
Mordant step of gram stain
Iodine
-purple +
-purple -
decolorizing stage of gram stain
Alcohol acetone
-purple +
- colourless -
Counterstain step in gram stain
Safranin
-purple +
-red/pink -
Why is there a difference in the gram stain
Due to difference in cell walls
Purple is absorbed by (positive or negative?)
Both
Colour is intensified and a CVI2 complex is formed (positive or negative?)
Both
Due to a stacked layer, the CVI2 complex remains stuck and stays purple (positive or negative?)
Positive cell wall
Peptidoglycan looses CVI2 due to outer membrane, then forms large holes (positive or negative?)
Negative cell wall
Function of acid fast stain
Detects TB and leprosy
-10 to 15 min but reliable and cheap
Why do we need acid fast when we have gram stain?
Acid fast can diagnose myocobacterium and ensure that the patient has this before starting treatment
Primary stage of acid fast
Carbolfushin
-red +
-red -
Decolorzing stage of acid fast
Acid alcohol
-red +
-colourless -
Counterstain stage of acid fast
Methylene blue
-red +
-blue -
After acid fast what colour is a patient who HAS myocobacterium?
RED
After acid fast what colour patient does not gave myocobacterium?
Blue
Types of special stains
-capsule
-Endospores
-flagella
Capsule stain
A way of determining if the cells contain a capsule
Capsule stain: acidic stain
Background will be very dark
Capsule stain: water wash
Objects can float away, so have to be careful and slow
Capsule stain: simple
Cells will have a hollowed out region, indicating capsule
Endospores stain
-clinically very important
Determining if there are Endospores present
Endospores stain: primary stain
-malachite green
-needs 6min of heat
Endospores stain: Counterstain
Green dot will appear in center of cell will show Endospores
Flagella stain
Shows flagella’s in cells
Flagella stain: carob fusion
-red due
Flagella stain: mordant
-potassium alum
Intensifies colour and diameter of flagella
Inconsistency in flagella stain
Flagella appears as frimbrae and floats away
