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(LEC) Microtome

Terms in this set (57)

Microtomy
A process where processed tissue is trimmed and cut into uniformly thin slices or sections to facilitate studies under the microscope
Microtome
An instrument that is capable of cutting a section at a predetermined thickness by sliding the block into a cutting tool which is fixed and attached to the machine.
Paraffin embedded tissue
Most commonly used specimen for microtomy
Microtome
An equipment that is capable of cutting a section
Ugly ribbon
Type of cut in microtomy that may lead to misdiagnosis
waterbath, drying oven or hot plate, forceps, clean slide, ice tray, pencil
Other equipments used in Microtomy (6)
block holder, knife carrier and knife, pawl, ratchet feed wheel, adjustment screw
Essential parts in Microtome (3)
Block holder
Part of microtome that holds the tissue in position
knife carrier and knife
Part of microtome that is for actual cutting of tissue
pawl, ratchet feed wheel, adjustment screws
Part of microtome that lines up the tissue block in position with the knife; adjusts the proper thickness of the tissue
rocking, rotary, sliding, freezing, cryostat, ultrathin
6 Kinds of Microtome
Rocking microtome
It is the simplest among the different types of microtome
Rocking microtome
Kind of microtome that is for serial sections of large blocks of paraffin embedded tissues
Cambridge microtome
What is the other term for rocking microtome?
Paldwell Trefall
Who is the inventor of rocking microtome?
1881
When was rocking microtome invented?
tissues are cut in slightly curved planes
Why is the rocking microtome not recommended for serial sections?
10-12 um
Ribbon thickness when using rocking microtome?
Has restrictions in size of tissue block that can be cut, difficulty in reorienting the block
Disadvantages of Rocking Microtome
Rotary microtome
It is the most common type used for both routine and research labs paraffin embedded sections What type of section is the rotary microtome used?
routine microtome, minot microtome
Other term for rotary microtome
Minot
Who is the inventor of rotary microtome?
1885 to 1886
When was rotary microtome invented?
Sliding microtome
A kind of microtome that has movable knives
celloidin embedded tissues
What type of specimen is the sliding microtome used?
Adams
Who invented the sliding microtome?
1789
When was sliding microtome invented?
base-sledge microtome
A microtome two movable pillars holding the adjustable knife clamps
Knife
In sliding microtome, this part sets at an angle for cutting celloidin sections
Standard sliding microtome
It remains stationary while the knife is moved backward and forward during the process of sectioning
Freezing Microtome
It is used for unembedded frozen sections
Queckett
Who invented the freezing microtome?
1848
When was the freezing microtome invented?
Cryostat
A refrigerated apparatus used for freezing the tissue into the block holder to correct the degree of hardness; for cutting frozen sections
-5 to -30 degcel
The cold chamber of cryostat is kept at what temperature?
-20 degcel
The average temperature for cold chamber of cryostat?
2-3 minutes
How long is the cryostat capable of freezing a fresh tissue?
4 um
Ribbon thickness of fresh tissue cut with cryostat
Ultrathin microtome
Used for tissue sections at 0.5 micra for Electron Microscopy
aqueous solution of an appropriate heavy metal
What is the stain used for sections in Ultrathin?
glass knife/industrial grade diamond knife
What is used to cut semi-thin sections prior to thin sectioning?
small, fixed in osmium tetroxide and embedded in plastic
What is the specimen used for Ultrathin microtome?
60 to 100 nm
Ribbon thickness in Ultrathin microtome
1)dust accumulation: must be prevented by putting a cover when not in use 2)moving parts: wiped regularly with good neutral oil to lubricate and avoid rust 3)after cutting: clean frequently from accumulated paraffin using a soft tissue brush with xylene 4)Screws: never to be adjusted too tightly because they may cause binding
Care for microtome
Plane concave, Biconcave, Plane Wedge
3 Types of Microtome knives
Plane-concave knife
Knife that is usually 25 mm in length
Less concave
Side of plane concave knife that is for celloidin embedded tissue blocks on a sliding microtome
More concave
Side of plane concave knife that is for paraffin sections on base-sledge, rotary or rocking
Biconcave knife
Knife that is 120 mm; for paraffin embedded sections on rotary
Plane-wedge knife
Knife that is 100 mm; both sides straight; frozen sections, extremely hard and tough spx embedded in paraffin blocks on base-sledge or sliding
Honing
It is the removal of gross nicks on the knife edge to remove blemishes and grinding the cutting edge of the knife on a stone to acquire an even edge
Belgium yellow
Honing that is for manual sharpening when cutting edge is blunt or nicked; gives the best result
Arkansas
Honing that gives a more polishing effect than Belgium Yellow
Fin Carborundum
Honing that is coarser; only for badly nicked knives followed by either one of the first two knife sharpeners
Stropping
A burr formed during honing is removed and the cutting edge of the knife is polished
Honing
Used to remove irregularities of a knife
Stropping
Used to polish and sharpen the cutting edge of the knife
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