MICROTOMY

Question 1

ESSENTIAL PARTS OF MICROTOME

Answer 1

1. Block holder - where the tissue is hold in position
2. Knife carrier and knife - for actual cutting of the tissue sections
3. Pawl, ratchet feed wheel and adjustment crews - to line up the tissue block in proper position with the knife, adjusting the proper thickness of the tissue for successive sections

Question 2

TYPES OF MICROTOME:

Answer 2

1. Rocking microtome/Cambridge microtome
2. Rotary microtome
3. Sliding microtome
4. Freezing microtome
5. Ultrathin microtome
6. Cryostat

Question 3

For cutting serial sections of LARGE BLOCK OF PARAFFIN EMBEDDED tissues; Simplest among the different types of microtome

Answer 3

Rocking microtome/Cambridge microtome

Question 4

Who invented the Rocking microtom?

Answer 4

Paldwell Trefall (1881)

Question 5

For cuting PARAFFIN EMBEDDED sections; MOST COMMON type used for both routine and research laboratories

Answer 5

Rotary microtome

Question 6

who invented the rotary microtome?

Answer 6

Minot (bet. 1885-1886)

Question 7

For cutting CELLOIDIN EMBEDDED sections; MOST DANGEROUS type of microtome due to movable exposed knife

Answer 7

Sliding microtome

Question 8

Types of sliding mcirotome:

Answer 8

1. Base-sledge: Movable block, stationary knife
2. Standard-slicing: Stationary block, movable knife

Question 9

Who invented the sliding microtome?

Answer 9

Adams (1789)

Question 10

For cutting UNEMBEDDED FROZEN SECTIONS that releases carbon dioxide that freezes tissues

Answer 10

Freezing microtome

Question 11

Who invented the freezing microtome?

Answer 11

Queckett (1848)

Question 12

For cutting plastic embedded sections for ELECTRON MICROSCOPE (EM)

Answer 12

Ultrathin microtome

Question 13

Optimum working temperature of Cryostat:

Answer 13

-18 to -20C

Question 14

Maintaining temperature of cryostat:

Answer 14

-5 to -30C (near -20C)

Question 15

Classification of microtome knives

Answer 15

1. Conventional steel knives
2. Disposable knives
3. Glass knives
4. Diamond knife

Question 16

Types of conventional knives:

Answer 16

1. Plane concave (25 mm in length)
2. Biconcave (120 mm in length)
3. Plane-wedge (100 mm in length)

Question 17

LESS CONCAVE SIDES are recommended for cutting __________________ tissue blocks on a sliding microtome

Answer 17

CELLOIDIN-EMBEDDED tissue blocks

Question 18

MORE CONCAVE SIDES are used to cut ________________ on base-sledge, rotary or rocking microtome

Answer 18

PARAFFIN SECTIONS

Question 19

Recommended for cutting PARAFFIN EMBEDDED SECTIONS on a ROTARY MICROTOME

Answer 19

Biconcave (120 mm in length)

Question 20

Recommended for FROZEN SECTIONS or for cutting EXTREMELY HARD AND TOUGH SPECIMENS, using a base-sledge type or sliding microtome

Answer 20

Plane-wedge (100 mm in length)

Question 21

MORE COMMONLY USED microtome knives nowadays since it is cheaper to use than conventional steel knives

Answer 21

Disposable blades

**MAGNETIC KNIVES - suitable use for CRYOSTAT

Question 22

Used for trimming and SEMI-THIN “survey” sectioning of tissue blocks for ELECTRON MICROSCOPY

Answer 22

Glass knives

Question 23

Used only for cutting ULTRA-THIN sections for electron microscopy

Answer 23

Diamond knife

Question 24

Sharpening of the conventional steel-knives

1st step:
2nd step:

Answer 24

Sharpening of the conventional steel-knives

1st step: HONING (HARD SHARPENING)
2nd step: STROPPING (POLISHING)

Question 25

Removal of GROSS NICKES on the knife to remove blemishes, and grinding the cutting edge of the knife on stone to acquire an even edge

Answer 25

HONING

Question 26

Removal of BURR formed during honing and polishing of the cutting edge of the knife

Answer 26

STROPPING

Question 27

Edge first, HEEL to TOE direction:

Answer 27

HONING

Question 28

Edge last, TOE to HEEL direction

Answer 28

STROPPING

Question 29

How many double strokes should be done in honing?

Answer 29

20-30 double strokes

Question 30

How many double strokes should be done in stropping

Answer 30

40-120 double strokes

Question 31

Dimension of hones:

Answer 31

8x3 inch

Question 32

Dimension of strops:

Answer 32

3-4x18 inch

Question 33

THREE TYPES OF HONES:

Answer 33

1. Belgium yellow 2. Arkansas 3. Fine carborundum

Question 34

type of hone that gives the BEST RESULT in honing

Answer 34

Belgium yellow

Question 35

type of hone that gives BETTER and MORE POLISHING effect

Answer 35

Arkansas

Question 36

Coarsest; type of hone for BADLY NICKED AND JAGGED knives

Answer 36

Fine carborundum

Question 37

Lubricants to be used in honing:

Answer 37

1. Soapy water 2. Mineral oil 3. Clove oil 4. Xylene or Liquid paraffin

Question 38

Stropping: uses paddle strop made of _______________ that are usually treated with _______________ or _____________ at the back and not the surface

Answer 38

Uses paddle strop made of HORSE LEATHER that are usually treated with VEGETABLE OIL or CASTOR OIL at the back and not the surface

Question 39

ANGLES IN TISSUE CUTTING

Answer 39

Bevel angle Clearance angle Wedge angle

Question 40

Angel formed between the cutting edge of the knife about 27-32 degrees

Answer 40

Bevel angle

Question 41

Angle formed between the cutting edge of the knife and the tissue block, 0 to 15 degrees angultaion;

Answer 41

Clearance angle

Question 42

Perfect and Optimum angle is:

Answer 42

15 degrees

Question 43

To prevent uneven section, angle is:

Answer 43

5-10 degrees

Question 44

Angle formed by the sides of the wedge knives, normally 14 to 15 degrees

Answer 44

Wedge angle