Types Of Microscopy (L1) Flashcards
Microscope use/What are microscopes used for?
To render visible objects as details that are too small to be seen by the unaided eye.
Resolving power (r.p.)?
= smallest separation at which we can see that 2 objects are present rather than one.
Magnifying power?
= how many times the apparent size of the object has been increased.
r.p. of the Human eye?
r.p. of 1/10mm (100μm).
r.p. of Light microscope?
0.2μm (200nm).
r.p. of Electron microscope?
0.2nm.
Types of microscopes (in order of resolution & area size of specimen used)? (3)
• Light microscope (LM).
• Scanning electron microscope (SEM).
• Transmission electron microscope (TEM).
Types of Light microscopes? (2)
• Stereobinocular microscope.
• Compound microscope.
Stereobinocular microscope is AKA?
Dissecting microscope.
Units used in Microscopy? (4)
• mm.
• μm.
• nm.
• pm.
Stereobinocular microscope?
= microscope where light is reflected off the surface of specimen or transmitted through it.
What is a Stereobinocular microscope used for?
Used for the dissection and/or the manipulation of objects.
Stereobinocular microscope attributes? (5)
• Shows gross morphology of specimens.
• No treatment needed.
• Have a lower resolution/low magnification than that of a compound microscope.
• 2 light sources (above and below).
• See 3D images (whole specimen).
Compound microscope?
= microscope where light is usually transmitted through the specimen.
What is the Compound microscope used for?
Used to examine tissues and some cellular details.
Compound microscope attributes? (4)
• 1 light source (below).
• See 2D images.
• Specimen is thinly sliced (treatment of specimen is often needed).
• When using it, never go to ×100 objective (only used for oil-immersed specimens).
SEM?
= microscope where the electron beam scans the surface of the specimen.
SEM attributes? (6)
• Allows for detailed examination of surface structures.
• Specimen must be treated.
• Produces SEM micrograph (greyscale).
• 3D images.
• Electron beam instead of light.
• Images are sometimes artificially coloured.
TEM?
= microscope where electron beams are transmitted through the specimen.
TEM attributes? (5)
• Examination of very small structures (eg, viruses, bacteria, internal cell structures, macromolecules).
• Very thinly sliced.
• TEM image: greyscale, ultrastructure of the cell.
• 2D images.
• Focuses on ultra structures.
Egs of small structures that are examined under a TEM? (4)
• Viruses.
• Bacteria.
• Internal cell structures.
• Macromolecules.
Units of measure used in Microscopy? (4)
• mm (millimetre).
• μm (micrometre).
• nm (nanometre).
• pm (picometre).
mm =…?
1×10^(-3) m
μm = …?
1×10^(-6) m
nm = …?
1×10^(-9) m
pm = …?
1×10^(-12) m
Calculation of scale and size attributes? (5)
• Determine the actual size of the structures shown.
• Scale bar/magnification should be given with micrographs.
• Descriptive heading below micrograph.
• Describe micrograph/drawing properly.
• Add scale bar & magnification.
Scale bar/magnification attributes? (3)
• Estimated, if only approximated size is required.
• Exact calculation can be acquired.
• Automatically done by camera/software.
Micrograph heading pointers? (4)
• Type of section.
• Specimen/structure.
• What was it stained with.
• Under which magnification.
