Misc. Instrumentation
What are the functions of the drying oven?
To dry slides since all water must be removed prior to deparaffinization, to adhere the section to the slide, and to melt paraffin.
3 types of maintenance for a microscope
1. Keep microscope covered when not in use
2. Clean the lenses frequently with lens paper.
3. Reduce the light to a minimum or turn it off when not in use.
4. Remove the slides from the stage when not in use.
5. Do not touch the surface of the lens with fingers
What is the clearance angle in relation to the block face when cutting sections?
3-8 degrees
The instrument used to produce a ribbon of sections off the tissue block
Microtome
What temperature is the paraffin in the embedding center kept at?
Paraffin is kept at 2-4 degrees Celsius above the melting point of the paraffin used.
When is a cryostat used?
When immediate microscopic evaluation is required for frozen sectioning.
The maximum magnification that can be obtained with most light microscopes is about
1000x
Name 3 steps of routine maintenance of the rotary microtome
1. Clean the microtome thoroughly at the end of each shift by removing paraffin with soft brush or cloth
2. Depending on microtome model, may require oil or grease to all sliding parts as indicated by manufacturer.
3. Document the service, repair, or routine preventive maintenance.
4. Cover the microtome when it is not in use.
This instrument is used to float out paraffin ribbons so that there are no folds, wrinkles or bubbles.
Water bath
What artifact can happen when the water bath temperature is too hot?
Parched earth
What are the major advanatages of a closed system tissue processor?
The tissue is in a closed environment and is safe from drying out. Also, if there is a power failure it is a battery back up, and there are no noxious fumes.
This type of microscope results in a 30-dimensional image
Scanning electron microscope
What are 3 advantages of the rotary microtome?
1. Produce large numbers of serial sections.
2. Can adjust clearance angle.
3. Stable due to stationary knife.
4. Can be motorized.
5. Easy to use.
1 micron= how many millimeters?
1/1000 of a mm or .001 of a mm
Commonly, cryostats are typically set to what temperature for most tissues?
-20 degrees Celsius
What instrument can be used in place of a drying oven or hot plate for drying slides?
Incubator
This microscope is used to examine tissue for substances exhibiting the phenomena of double refraction, anisotropism, and birefringence.
Polarizing microscope
What are the 2 disadvantages of the sledge/sliding microtome?
1. Sectioning is a slow process
2. Serial sections aren't formed in a ribbon
What are the 4 requirements for successful sectioning?
1. Skilled technician
2. Sharp microtome blade
3. Proper microtome
4. Properly prepared material
What is the correct temperature for the water bath?
Temperature is ideally kept at 5-10 degrees below the melting point of the paraffin. (47-51 degrees Celsius)
What does a microwave tissue processor do?
Uses microwave technology to create friction which generates heat to rapidly warm the chemicals and speed processing.
Objectives of a microscope should be parfocal. What does that mean?
All objectives will have the focal point in the same plane, and magnification, or objectives, can be changed without refocusing.
When is a sledge or sliding microtome used?
For sectioning celloidin and large paraffin blocks.
When are diamond knives used during sectioning?
When sectioning the hardest materials and used for ultra thin sectioning in electron microscopy
Approximately 4 degrees Celsius