Quiz 2

Question 1

• The block remains stationary while the knife is moved backward and forward during the process of sectioning.
• Developed mainly for cutting celloidin-embedded tissue blocks
• Inherently more dangerous

Answer 1

Standard sliding microtome

Question 2

• Invented by Queckett in 1848
• The stage for block holder is hollow and perforated around its perimeter, attached to a reinforced flexible lead pipe thru which carbon dioxide passes from a cylinder.

Answer 2

Freezing Microtome

Question 3

*A simple lever operated valve allows the release of rapid intermittent burst of carbon dioxide.
*A second cooling device for lowering temperature of the knife to facilitate sectioning.

Answer 3

Freezing Microtome

Question 4

*Indications:
* Used to cut undehydrated tissues in a frozen state
* When histological demonstration of fat is needed
* When certain neurological structures are to be studied
* When sensitive tissue constituents to be studied are
damaged or destroyed by heat.

Answer 4

Freezing Microtome

Question 5

• Consists of microtome kept inside a
  cold chamber which has been
  maintained at a temperature
  between -5 to -30°C (-20°C) by an
  adjustable thermostat
• Capable of freezing fresh tissues
  within 2-3 minutes
• Can cut sections of 4µ with ease.

Answer 5

Cryostat

Question 6

• Provides a means of preparing thin
  sections of fresh frozen tissues for
  fluorescent antibody staining
  techniques or histochemical
  enzyme studies.
• Most commonly used for rapid
  preparation of urgent tissue
  biopsies for intraoperative
  diagnosis.

Answer 6

Cryostat

Question 7

are used to mount tissues in the Cryotome

Answer 7

OCT

Question 8

• Primarily used for cutting tissue sections at 0.5 micra for
  electron microscopy.
• The knife used for cutting the ultrathin sections consists mainly of selected fragments of broken plate glass.
• The specimen used is small, fixed in osmium tetroxide, and embedded in plastic.

Answer 8

Ultrathin Microtome

Question 9

Kinds of Microtome

Answer 9

• Vibrating Microtome
• Hand Microtome
• Saw Microtome
• Laser Microtome
• Computerized Microtome

Question 10

Care of the Microtome

All the accumulated paraffin and small pieces of tissues must be brushed away with soft brush and not allowed to stay in the microtome

Answer 10

True

Question 11

Care of the Microtome

After drying the machine and knife holder, the parts should be wiped with xylol

Answer 11

True

Question 12

Care of the Microtome

Microtome must always be covered
when not in use.

Answer 12

True

Question 13

Care of the Microtome

Movable portions should be oiled
thoroughly to prevent rusting

Answer 13

True

Question 14

Types of Microtome Knives

• Usually 25 mm in length
• One side of the knife is flat while the other is concave.

Answer 14

Plane-concave knife

Question 15

Types of Microtome Knives

• Usually 120 mm in length
  *With both sides concave, recommended for cutting paraffin embedded sections on a rotary microtome.

Answer 15

Biconcave knife

Question 16

Microtome Knives

• Usually 100 mm in length
• Have both sides straight
• Recommended for frozen sections or for cutting extremely hard and tough specimens embedded in paraffin blocks using a base-sledge type or sliding mircrotome.

Answer 16

Plane-wedge knife

Question 17

Microtome Knives

• Have a sharp cutting edge that can cut 2-4 µ thick sections with ease.
• Cheaper to use

Answer 17

Disposable Blades

Question 18

Microtome Knives

Used for trimming and semi-thin sectioning of tissue blocks for electron microscopy.
* Commercially prepared
* Should be prepared and stored in dust-free boxes with lids, just before use, to avoid contamination.

Answer 18

Glass Knives

Question 19

Microtome Knives

• Used to cut any type of resin block for electron microscopy
• Are brittle and expensive, but very durable
• They are already mounted in a metal block designed to fit directly into the knife holder of the ultrathin microtome when purchased.

Answer 19

Diamond Knives

Question 20

Other Equipment For Tissue Sectioning

• Temperature: About 10°C below the melting point of the paraffin wax.
• A small amount of detergent may be added to water to reduce surface tension and allow section to flatten out.

Answer 20

Floatation Water Bath

Question 21

Other Equipment For Tissue Sectioning

• Temperature is set at the melting point of the wax,to 2-5 degrees Celsius above* (*Gregorio’s)

Answer 21

Drying oven or hot plate

Question 22

Other Equipment For Tissue Sectioning

• Both are needed for handling sections during cutting and removing folds and creases during “floating out” in waterbath.

Answer 22

Forceps and squirrel/camel hairbrush

Question 23

Other Equipment For Tissue Sectioning

Clean slides and Coverslips