Manual - Instrumentation in Histotechnology

Question 1

The earliest form of microtomy was the freehand sectioning of fresh or fixed material using a

Answer 1

sharp razor

Question 2

are precision instruments
designed to cut uniformly thin sections of a variety of material for detailed microscopic examination.

Answer 2

Modern microtomes

Question 3

Parts of a microtome

Answer 3

Block holder
Knife stand/holder
Thickness scale
flywheel
Knife stand clamp
Knife

Question 4

• This type of microtome is generally used for cutting semi-thin to thin sections
  of paraffin wax embedded material for light microscopy.

Answer 4

Rotary Microtome

Question 5

Rotary Microtome
Paraffin embedded tissues are normally cut between_______

Answer 5

3 to 5 µm

Question 6

The operation of the microtome is based upon the rotary action of a hand wheel activating
the advancement of a block towards a rigidly held knife.

The block moves up and down in a vertical plane in relation to the knife and therefore it cuts flat sections.

Answer 6

Rotary microtome

Question 7

The knife holding clamps allow the knife to be offset to one direction, a major advantage
when sectioning large, hard blocks.

They are not suitable for cutting very hard resins such as araldite because of the risk of vibration

Answer 7

Sliding Microtome

Question 8

• These are designed for cutting large blocks of paraffin and resin embedded
  material including whole organs, for light microscopy.

Answer 8

Sliding Microtome

Question 9

The rocking
microtome was invented by _______(1851-1928), the son of
Charles Darwin.

Answer 9

Sir Horace Darwin

Question 10

• The razor of this microtome is fixed and the specimen to be sliced for microscopic examination passes up and down in an arc of a circle across the razor in a rocking motion.

Fixed on to a table, the ribbons of specimen
fell to the desk top then were cut and mounted on to slides.

Answer 10

Rocking Microtome

Question 11

Freezing Microtome
* This form of microtome is used for cutting thin to semi-thin (about _______)
sections of fresh, frozen tissue.

Answer 11

8-12µm

Question 12

is equipped with a stage upon which tissue can be quickly frozen using either liquid carbon dioxide, from a cylinder, or a low temperature recirculating coolant.

Some cooling systems also allow the knife to be cooled at the same time. The
cutting action of the freezing microtome differs from those described
previously as in this case the knife is moved while the tissue block remains
static.

Consistent, high quality, thin sections are very difficult to obtain with
this type of microtome.

Answer 12

The freezing microtome

Question 13

is primarily used for cutting sections of frozen tissue. It commonly consists of a microtome contained within a refrigerated chamber, the temperature of which can be maintained at a preset level.

Answer 13

Cryostat

Question 14

The cryostat usually contains a _______ microtome although some portable units utilize a rocking microtome.

With the block, blockholder and knife all at the same temperature and all other conditions for
cutting the material optimal, sections as thin as _____ are possible.

Answer 14

rotary

1 micron

Question 15

• It is used to prepare ultrathin sections for light and electron microscopy. Very small samples of tissue are usually embedded in hard resin before cutting.

Answer 15

Ultrathin microtome

Question 16

The cutting stroke is motor driven to provide a regular, smooth motion for sections of even thickness and constant reproducibility.

Answer 16

ultrathin microtome

Question 17

Ultrathin microtome

Knives are usually made from (3)

The block is brought to the knife edge under microscopic control and as each section is cut it is floated on to a water bath adjacent to the knife edge.

Answer 17

glass, diamond or sapphire

Question 18

• These are used for floating the paraffin ribbon.

Answer 18

FLOTATION BATH OR WATER BATH

Question 19

Water BATH

Temperature depends on a degree of the personal preference of the microtomist, but it is recommended to maintain a temperature of ______ degrees below the melting point of the
paraffin used during embedding.

Answer 19

5 to10

Question 20

These are used for drying the water that is
collected during the sectioning of tissue section.

Answer 20

Slide dryers

Question 21

Water Bath
The temperature used is between _____
degrees above the melting point of the paraffin.

Answer 21

5 - 10

Question 22

Water Bath

Slides are left to dry for approximately _____
minutes, after they have been appropriately
drained.

Not doing so can cause the bubbling
under the tissue sections.

Overheating slides may cause uneven staining as well as artifacts

Answer 22

15-20

Question 23

is used to heat and speed some procedures. Some special stains techniques are performed in the ________.

Answer 23

MICROWAVE OVEN

Question 24

• It is a complete system designed for
  embedding tissue in paraffin.

It provides a controlled heated environment (paraffin is kept at _________ above its melting point) for the processed cassettes and eliminates xylene contamination.

Answer 24

Embedding Centers
2 - 4ºC

Question 25

transfer slides from one container to the next container with the same time allowed in each container.

_______ are similar to the linear stainer and the time allowed in each can be varied.

_______ are flexible with computerized programming that allows the
continuous loading and use of the same solutions at different timing.

Answer 25

AUTOMATED STAINERS

Linear types
Revolving types
Robotic ones

Question 26

• Maintains the paraffin wax in liquid form and aids in dispensing of wax into molds or casts.

Answer 26

PARAFFIN WAX DISPENSER