MICROTOMY / SECTIONING
So after embedding, may tissue MICROTOMY / SECTIONING
block ka na, now the next step is TO 3 TYPES OF TISSUE SECTIONS
CUT. Paraffin uses ROTARY microtome Usual thickness
sections is 4-6um
Sectioning – Cutting tissues into
thin slices/tissue sections called Celloidin Uses SLIDING microtome (Not commonly 10-15um
sections prepared ata)
ribbons.
Frozen Frozen sections are prepared using RAPID
sections DIAGNOSIS. Used in 2 ways: COLD KNIFE 4um
(cryostat) procedure and CRYOSTAT method / COLD
microtome btch see below
Frozen sections are prepared using RAPID DIAGNOSIS (The px is still in the OR)
Microtome – cutting engine in histopath; Equipment used for cutting tissues
6 TYPES OF MICROTOMES
Rocking microtome / Cambridge
▪ Invented by Trefall
▪ MOST SIMPLE among the 6 types
▪ Thickness of sections: 10-12um
▪ Purpose: To prepare serial sections of large paraffin blocks
ROTARY MICROTOME
▪ MOST COMMON type among the 6 types
▪ Thickness of sections: 4-6um
▪ Invented by Minot
▪ Purpose: Used to cut paraffin embedded tissues
SLIDING MICROTOME ▪ Invented by Adams
▪ MOST DANGEROUS among the 6 types (bcos of the exposed knife)
▪ Thickness: 7-9um
▪ Purpose: Used only to cut celloidin embedded tissues / to cut
extremely hard/tough tissues
▪ types of sliding microtome:
1. Base sledge: Less dangerous than standard because here, the movable part
is the block holder and the one that remains stationary is the knife.
2. Standard sliding: Most dangerous because the movable part is the knife.
(kabaligtaran ng base)
, ULTRATHIN MICROTOME ➢ Purpose: For cutting tissues for EM (electron microscopy)
➢ Thickness of sections: .5um
FREEZING MICROTOME ▪ Invented by Queckette
▪ Uses: Intermittent burst of CO2 (Carbon dioxide)
▪ Freezing agent: CO2 to immediately harden fresh tissues in order to
facilitate immediate cutting kasi nga for rapid diagnosis to
▪ Purpose:
a. To prepare frozen sections for cold knife procedure
b. For demonstration of fats & other neurological structures
c. To cut tissues with heat sensitive structure
▪ Thickness of sections: 10-15um
CRYOSTAT / COLD MICROTOME ▪ CRYOSTAT is a refrigerated apparatus (a microtome that is enclosed in
a cold chamber usually a ROTARY microtome)
▪ For fresh tissues microtomy: Refrigerated with a temperature of -5 to
-30degC but the average is -20degC.
▪ So dito, to immediately harden the tissues, yung cold chamber with a
rotary microtome ang gamit kasi nga for rapid diagnosis din to.
▪ For preparing thin sections of fresh frozen tissues for fluorescent
antibody staining or histochemical enzyme studies.
So, halos pareha lang ang freezing at cryostat/cold microtome kase they can immediately harden tissues to
facilitate immediate cutting.
In the lab, we usually prepare 2 types of sections:
1. Paraffin section
2. FROZEN SECTION = for rapid dx
METHODS OF PREPARING FROZEN SECTIONS IN GENERAL
Cold knife procedure You need to have a freezing microtome
Cold microtome / Cryostat method (See above)
3 MICROTOME KNIVES
(Traditionally lang to kase di na gumagamit ng microtome knives ngayon, DISPOSABLE
BLADES na) → BOARDS
PLANE ▪ 25mm long
CONCAVE ▪ One side of the knife is flat and the other side is concave
▪ Double purpose:
a. Concave side = For cutting paraffin embedded tissues
b. Flat side = For cutting celloidin embedded tissues
BICONCAVE ▪ 120mm long
▪ Both sides are concave
▪ Used to cut paraffin embedded tissues (kasi nga concave side
lang meron)
PLANE ▪ Usually, 100mm long
WEDGE ▪ Both sides of the knife are FLAT
▪ Recommended to cut frozen sections and extremely hard or
tough tissues
So after embedding, may tissue MICROTOMY / SECTIONING
block ka na, now the next step is TO 3 TYPES OF TISSUE SECTIONS
CUT. Paraffin uses ROTARY microtome Usual thickness
sections is 4-6um
Sectioning – Cutting tissues into
thin slices/tissue sections called Celloidin Uses SLIDING microtome (Not commonly 10-15um
sections prepared ata)
ribbons.
Frozen Frozen sections are prepared using RAPID
sections DIAGNOSIS. Used in 2 ways: COLD KNIFE 4um
(cryostat) procedure and CRYOSTAT method / COLD
microtome btch see below
Frozen sections are prepared using RAPID DIAGNOSIS (The px is still in the OR)
Microtome – cutting engine in histopath; Equipment used for cutting tissues
6 TYPES OF MICROTOMES
Rocking microtome / Cambridge
▪ Invented by Trefall
▪ MOST SIMPLE among the 6 types
▪ Thickness of sections: 10-12um
▪ Purpose: To prepare serial sections of large paraffin blocks
ROTARY MICROTOME
▪ MOST COMMON type among the 6 types
▪ Thickness of sections: 4-6um
▪ Invented by Minot
▪ Purpose: Used to cut paraffin embedded tissues
SLIDING MICROTOME ▪ Invented by Adams
▪ MOST DANGEROUS among the 6 types (bcos of the exposed knife)
▪ Thickness: 7-9um
▪ Purpose: Used only to cut celloidin embedded tissues / to cut
extremely hard/tough tissues
▪ types of sliding microtome:
1. Base sledge: Less dangerous than standard because here, the movable part
is the block holder and the one that remains stationary is the knife.
2. Standard sliding: Most dangerous because the movable part is the knife.
(kabaligtaran ng base)
, ULTRATHIN MICROTOME ➢ Purpose: For cutting tissues for EM (electron microscopy)
➢ Thickness of sections: .5um
FREEZING MICROTOME ▪ Invented by Queckette
▪ Uses: Intermittent burst of CO2 (Carbon dioxide)
▪ Freezing agent: CO2 to immediately harden fresh tissues in order to
facilitate immediate cutting kasi nga for rapid diagnosis to
▪ Purpose:
a. To prepare frozen sections for cold knife procedure
b. For demonstration of fats & other neurological structures
c. To cut tissues with heat sensitive structure
▪ Thickness of sections: 10-15um
CRYOSTAT / COLD MICROTOME ▪ CRYOSTAT is a refrigerated apparatus (a microtome that is enclosed in
a cold chamber usually a ROTARY microtome)
▪ For fresh tissues microtomy: Refrigerated with a temperature of -5 to
-30degC but the average is -20degC.
▪ So dito, to immediately harden the tissues, yung cold chamber with a
rotary microtome ang gamit kasi nga for rapid diagnosis din to.
▪ For preparing thin sections of fresh frozen tissues for fluorescent
antibody staining or histochemical enzyme studies.
So, halos pareha lang ang freezing at cryostat/cold microtome kase they can immediately harden tissues to
facilitate immediate cutting.
In the lab, we usually prepare 2 types of sections:
1. Paraffin section
2. FROZEN SECTION = for rapid dx
METHODS OF PREPARING FROZEN SECTIONS IN GENERAL
Cold knife procedure You need to have a freezing microtome
Cold microtome / Cryostat method (See above)
3 MICROTOME KNIVES
(Traditionally lang to kase di na gumagamit ng microtome knives ngayon, DISPOSABLE
BLADES na) → BOARDS
PLANE ▪ 25mm long
CONCAVE ▪ One side of the knife is flat and the other side is concave
▪ Double purpose:
a. Concave side = For cutting paraffin embedded tissues
b. Flat side = For cutting celloidin embedded tissues
BICONCAVE ▪ 120mm long
▪ Both sides are concave
▪ Used to cut paraffin embedded tissues (kasi nga concave side
lang meron)
PLANE ▪ Usually, 100mm long
WEDGE ▪ Both sides of the knife are FLAT
▪ Recommended to cut frozen sections and extremely hard or
tough tissues
