Microtomy Flashcards
(31 cards)
a process whereby tissues are cut into thin slices
microtomy/sectioning
3 general types of tissue sections
celloidin, paraffin, frozen
Process of cutting off excess wax from the tissue block to expose
the tissue surface
trimming
cacapable of cutting a section at a predetermined thickness by sliding the block into a cutting
tool
microtome
usually a steel knife, glass or diamond blade, which is fixed and attached to the machine
microtome
3 essential parts of microtome
block holder, knife carrier and knife, pawl, ratchet feed wheel and adjustment screws
where the tissue is held in position.
Block Holder
for actual cutting of tissue sections.
Knife Carrier and Knife
to line up the tissue block in proper
position with the knife, adjusting the proper thickness of the tissue for successive sections.
Pawl, Ratchet Feed Wheel and Adjustment Screws
principle of microtome
a spring-balanced teeth or pawl is brought into contact with, and turns a ratchet
feed wheel connected to a micrometer screw, which is in turn rotated, moving the
tissue block at a predetermined distance towards the knife for cutting sections at
uniform thickness
-The simplest microtome, for cutting serial
sections of large blocks
of paraffin embedded
tissues
rocking microtome
most common microtome ,for paraffin-
embedded sections
rotary microtome
-The most dangerous
type of microtome and for celloidin embedded sections
sliding microtome
-for unembedded
frozen sections
Freezing microtome
-Capable of freezing
tissues in 2-3 minutes
*Cryostat/cold microtome
-for cutting sections for
electron microscopy
Ultrathin microtome
Recommended knife for cutting
PARAFFIN embedded
sections on a ROTARY
MICROTOME
biconcave knife
Recommended knife for FROZEN SECTIONS or for cutting extremely hard and tough specimens embedded in PARAFFIN blocks, using a BASE-SLEDGE or SLIDING MICROTOME
PLANE-WEDGE KNIFE
Recommended knife for cutting
CELLOIDIN embedded tissues
blocks on a SLIDING
MICROTOME
PLANE CONCAVE KNIFE
Angle formed between the cutting edges (27 o - 32 o)
BEVEL ANGLE
knife is usually tilted at 0-15° angulation on a
microtome to allow a clearance angle between the
cutting facet and the tissue block
CLEARANCE ANGLE
purpose of sharpening the blade
to remove irregularities with the use of
HONES
types of hones
Belgium Yellow, Arkansas, Fine carborundum
Gives the BEST RESULT (type of hone)
Belgium Yellow
