Microtomy Flashcards
Rocking microtome was invented by
Paldwell trefall
Thickness of cambridge
10-12 um
Tissues are cut in slightly curved planes thus not recommended for serial sections
Rocking micro
Most common and its thickness
Rotary; 3-5 um
Used for routine and research laboratories
Rotary
Rotary invented by
Minot 1885-86
Knife and block holder are brought together by upward and vertical motions, cutting sections in a perfectly flat plane;
Rotary
Sliding microtome developed by
Addams 1789
√ electrically
driven and ideal for RESIN-EMBEDDED
decalcified bone.
Base sledge microtome
knife is moving; the MOST DANGEROUS type of microtome because of the exposed, movable blade.
STANDARD SLIDING MICROTOME
Recommended for cutting “extremely” hard and rough tissue blocks
SLIDING
Recommended for cutting “extremely” hard and rough tissue blocks
SLIDING
Both Microtome, the knife can be set OBLIQULEY for celloidin or straight large paraffin.
SIIDING
Freezing microtome invested by
Quickett 1848
Freezing agent of freezing microtome
Co2
Used to cut undehydrated tissues in a frozen state.
Freezing micro
Ideal for fresh tissues that did NOT UNDERGO FIXATION down to INFILTRATION.
FREEZING MICRO
Used for RAPID preparation of URGENT tissue biopsies
for intraoperative diagnosis (STAT).
CRYOSTAT
Chamber of cryosat temp
-5 to -30C
Capable of freezing fresh tissue within 2-3 minutes.
Thermostat
Cutting section of thermostat
4um
Fluorescent antibody staining technique or histochemical enzyme studies.
Cryostat
For electron microscopy, tissues fixed with osmic
acid.
Ultrathin micro
Media of uultrathin micro and thickness
Plastc; 0.5 um
Uses diamond knife
Ultrathin
Types of tissue sections
Paraffn
Celloidin
Frozen sections
Sections are removed in RIBBONS OF TEN to allow easy location of serial sections
Paraffin
Thickness of paraffin
4-6um
Thickness of celloidin
10-15 um
To avoid dehydration and shrinkage, sections are usually cut by the WET method,
CELLOIDIN
In celloidin, sections and the block being kept moist with — during cutting.
Sections do not come off in -
70% alcohol
Ribbons
Microtome knives
Plane-concave
Biconcave
Plane-wedge
Widely use blade for 10 tissue blocks
Disposable blades
Disposable blade is coated w
Polytetrafluoroethylene
For ultrathin microtomes.
Glass knive/ralph knive
For RESIN blocks on ultrathin
microtomes;
● Brittle and expensive
Diamond knives
Blades For partially calcified materials, paraffin, and frozen sections.
Safety razor blades
Blades
Unsatisfactory for sections less
than 10 micro.
Safety razor blade
Bevel angle
27-32
Cutting angle
14
Angle between the UPPER facet of the knife and the SURFACE of the tissue block.
Cutting angle
Angle between the LOWER facet of the knife and the SURFACE of the tissue block;
CLEARING ANGLE
Clearing angle should be inclined at
5-10
2 stages of sharpening
Honing
Stropping
Removing of GROSS nicks
Honing
HEEL TO TOE
HONNING
TOE TO HEEL
STROPPING
Final polishing of the knife edge
STROPPPING
Removal of burr/irregularities
STROPPING
Knife sharpeners for finall polishing
Diamantine
— is used in stropping
Paddle strop
Never used with Pap Staining Method as it will retain OG stain;
Mayer’s egg albumin
Outdated blood stored in blood banks, dispensed into sterile tubes of 0.5 ml each.
Plasma
Better adhesion than albumin
1% Gelatin
Does NT RETAIN the stain.
1% METHYL CELLULOSE
ADHESIVE
No background staining
Poly-L Lysine
Slight dye retention, not affected by mild alkaline solutions 3 months.
STRONG ADHESIVE
SODIUM SLICATAE
Diluted 1:10 with acetone;
RESIN
Selected sections for staining should fish-out in a — POSITION
VERTICAL
Sections are floated out on a water bath set at
45-50°C.
Temp of slide dryer
5-10°C above the melting point of paraffin
In drying slides, hot plates are not recommended because
Overheating
Dust falling onto section
Mounted sections are placed in — for - miutes
Paraffin oven; 5 min
Process of trim and embedding
Trim tissue
Cool block w ice
Cut tissue -> make ribbons
Float tse in water bath
Pick up tissue on slide
Dry
Ideal shape in trimming
Truncated pyramid
