Sectioning

Question 1

embedded tissue is trimmed and cut into uniformly thin slices using a microtome

Answer 1

Sectioning

Question 2

The microtome consists of 3 essential parts, namely:

Answer 2

Block Holder (Chuck holder)

Knife carrier and knife

Pawl, Ratchet Feed Wheel and Adjustment screws-

Question 3

where the tissue is held in position

Answer 3

Block Holder (Chuck holder)

Question 4

for actual cutting of tissue sections

Answer 4

Knife carrier and knife

Question 5

to line up tissue block in proper
position with the knife, adjusting the proper thickness of the tissue

Answer 5

Pawl, Ratchet Feed Wheel and Adjustment screws

Question 6

▫ Simplest Microtome
▫ For serial sections of large paraffin
embedded tissue

10-12 μ

Answer 6

Rocking Microtome (Cambridge Microtome)

Question 7

▫ Most common type/ routinely used
▫ For routine paraffin embedded tissues
and Research laboratory

4-6 μ

Answer 7

Rotary Microtome

Question 8

▫ Most dangerous type
▫ Recommended for celloidin, ester wax
blocks

7-9 μ

Answer 8

Sliding Microtome

Question 9

2 types of Sliding Microtome:

Answer 9

a. Standard Sliding
b. Base Sledge/Sledge Type

Question 10

▫ More dangerous
▫ Movable part is the knife for extremely
hard & rough tissues

7-9 μ

Answer 10

Standard Sliding

Question 11

▫ Prefer to use
▫ Movable part is the block holder

7-9 μ

Answer 11

Base Sledge/Sledge Type

Question 12

▫ Uses intermittent burst of CO2 that will freeze the block
▫ For cutting undehydrated tissues, neurological tissues, demonstration of fats

10-15 μ

Answer 12

Freezing Microtome

Question 13

used as a propellant in Freezing Microtome

Answer 13

CO2

Question 14

▫ For fresh tissue microtome
▫ For fluorescent antibody staining or histochemical enzyme studies

4μ

Answer 14

Cryostat or Cold Microtome

Question 15

Cryostat or Cold Microtome
*tissues are refrigerated: ( __________)
*average _______

Answer 15

*tissues are refrigerated: ( -5 °C to –30 °C ) *average –20 °C

Question 16

▫ For electron microscopy
▫ Uses diamond knife

0.5-1 μ

Answer 16

Ultrathin Microtome

Question 17

Microtome Knives
-Mostly made up of

Answer 17

stainless steel

Question 18

Plane Concave

SIDE

USE

LENGTH

Answer 18

Flat & Concave
*Less Concave- for celloidin *More concave- for paraffin

Base Sledge Rotary Microtome Rocking Microtome

25 mm

Question 19

Biconcave

SIDE

USE

LENGTH

Answer 19

Both sides are Concave

Rotary Microtome

120 mm

Question 20

Plane Wedge

SIDE

USE

LENGTH

Answer 20

Both sides are Flat

Base Sledge/
Sliding Microtome
*For Frozen section/ very hard tissues

100 mm

Question 21

Bevel angle

Answer 21

27-32°

Question 22

Cutting angle

Answer 22

15°

Question 23

Clearance angle

Answer 23

0-15°

Question 24

Rake angle

Answer 24

Not stated

Question 25

Wedge angle

Answer 25

14-15°

Question 26

-KNIFE HARD SHARPENING -grinding the cutting edges to acquire even size edge Purpose: to remove blemishes & grinding the cutting

Answer 26

Honing

Question 27

Honing movement

Answer 27

HEEL to TOE MOVEMENT

Question 28

How many strokes in honing?

Answer 28

Uses 10-20, 20-30 strokes

Question 29

Hones/Oil stones used in honing (3)

Answer 29

a. Belgium Yellow: gives best results b. Arkansas: with more polishing effects c. Fine Carborundum: for badly nicked knives

Question 30

Lubricants used in honing (4)

Answer 30

a. Xylene/liquid paraffin b. Mineral oil c. Clove oil d. Soapy water

Question 31

removal of the tissue ribbon from the float out bath

Answer 31

Fishing out

Question 32

Flotation Water Bath: temperature

Answer 32

5-10 °C lower than the melting point or 45-50 °C

Question 33

-POLISHING Purpose: removal of burrs (irregularity of knife formed after honing)

Answer 33

Stropping

Question 34

Movement for stroping

Answer 34

TOE to HEEL MOVEMENT

Question 35

How many strokes for stroping?

Answer 35

40-120 double Strokes

Question 36

Stroping Uses PADDLE STROP made of horse leather that are usually treated with _________ oil or ________ oil at the back and not on the surface

Answer 36

Uses PADDLE STROP made of horse leather that are usually treated with Vegetable oil or Castor oil at the back and not on the surface

Question 37

Types of Sections:

Answer 37

Paraffin sections Celloidin sections Renal biopsy sections Ultra-thin sections Frozen section (cryostat)

Question 38

Sizes of different sections: Paraffin sections Celloidin sections Renal biopsy sections Ultra-thin sections Frozen section (Cryostat)

Answer 38

o Paraffin sections: 4-6 μm sections (average: 5) o Celloidin Sections: 10-15 μm sections o Renal Biopsy sections: 2 μm section *Semi-thin sections using plastic embedding medium o Ultra-thin sections (EM) *Recommended section: 80nm (silver or straw colored sections) o Frozen section (Cryostat): 4 μm if microtome used is Rotary

Question 39

Drying Technique for Slides (3)

Answer 39

1. Leave the slide in 37 °C incubator overnight 2. Place the slide in oven for 2 hrs in 56-60°C 3. Use a hot plate with 45-55°C for 30-45 minutes

Question 40

Adhesives (10)

Answer 40

Mayer’s Egg Albumin Dried Albumin 1% Gelatin Gelatin-Formaldehyde Mixture Starch Paste Plasma/Pooled Serum Poly-L-Lysine APES or 3-aminopropylthriethoxysilane Sodium Silicate Resins

Question 41

Most common Equal amount of Egg white and Glycerin

Answer 41

Mayer’s Egg Albumin

Question 42

Dried albumin + sodium chloride Addition of THYMOL CRYSTALS to prevent growth of molds

Answer 42

Dried Albumin

Question 43

Composed of Gelatin, Distilled water, Glycerol and phenol crystals Provides firmer attachment than albumin Added to the flotation water bath Disadvantage: Stains with many dyes

Answer 43

1% Gelatin

Question 44

1% Gelatin + 2% Formaldehyde

Answer 44

Gelatin-Formaldehyde Mixture

Question 45

Powdered starch, distilled water and HCL Addition of thymol crystals to prevent growth of molds

Answer 45

Starch Paste

Question 46

Readily available from outdated blood stored in blood banks

Answer 46

Plasma/Pooled Serum

Question 47

Effective as an adhesive, slowly decreases in time Widely used as an adhesive in immunohistochem

Answer 47

Poly-L-Lysine

Question 48

Recommended for cytology

Answer 48

APES or 3-aminopropylthriethoxysilane

Question 49

Commercial syrup=1:10 dilution Had strong adhesive properties

Answer 49

Sodium Silicate

Question 50

Greatest adhesion

Answer 50

Resins