Microscopy Flashcards
What 3 types of cell exist in single cell form?
Spermatozoa, Ovum & Blood Cells
What is used to preserve tissue and prevent rotting before light microscopy?
Formalin
What substance is the tissue embedded in to allow very thin slicing in light microscopy? To what typical thickness is the tissue cut?
Melted Paraffin.
5 micrometres.
What stain is commonly used to make the nucleus of cells look clearer and to show more detail in the cytoplasm? What colour does it give?
Haemotoxylin + Eosin (H + E Stain)
Purple
What does a haemotoxylin stain do to a cell?
Stains the nucleus most strongly blue
What does Eosin stain do to a cell?
Stains the extracellular matrix and cytoplasm most strongly pink
When taking a frozen section what temperature is the specimen reduced to? What is an advantage and disadvantage of this technique?
-20 to -30 degrees Celsius.
Much faster than traditional techniques.
Lower technical quality of the sections.
What causes gout? What is a common place for gout to be seen?
Too much uric acid. Formation of monosodium urate crystals especially at joints.
Big toe.
What is analgesia?
Rapid pain relief
What types of drugs can be used to treat the pain as a result of gout?
Non-steroidal anti-inflammatory drugs
What type of microscopy can be used to study living cells?
Confocal Microscopy
What is the common magnification of a light microscope?
1000x
What is the difference between resolvable points when using a light microscope?
0.2 micrometres
Do you get a higher resolution with a shorter or longer wavelength in microscopy? What is the wavelength used in light and TE microscopy?
Shorter wavelength
Light = 400nm
TEM = 1nm
TEM has a 400x greater resolution
What is the typical magnification of a TEM?
250,000x
Why can’t TEM be used to examine living structures?
Electron beam is fired in a VACUUM
How does the electron beam fired in TEM produce an image?
Fired at tissue. Portions that the beam passes through will appear brighter. Portions that absorb/scatter the electrons will appear darker.
What is used to fix a sample in TEM? What is the sample embedded in?
Glutaraldehyde.
Epoxy Resin.
What tool is used to slice samples extremely thinly?
Microtome
How does freeze fracture EM work?
Tissue frozen to -160 degrees Celsius.
Fractured with a knife - sample interior exposed.
How does SEM work?
Electrons fired at sample, reflected back from the surface of sample and received by cathode ray tube.
What is a cyrostat?
Microtome in a freezer. Used to produce a frozen section.
What is autoradiography?
Photographic emulsion is used to visualise molecules that are labelled with a radioactive marker.
Marker injected into live animal/cell culture.
