Module 3: Specialized Microscopes

Question 1

Fluorescence microscopy (UV, FA microscopy)

Answer 1

Identification of specific organisms, cells, or tissue components
Fluorescent dyes excited by short wavelength (UV), emit light of longer wavelength (visible)
Monoclonal antibody conjugate with fluorescent label

Question 2

Fluorescence microscope components

Answer 2

Mercury vapour lamp
Heat barrier
Excited (Woods) filter
Barrier filter

Question 3

Epi (incident) fluorescence

Answer 3

No condenser (don't set Kohler) - easier alignment
Light comes from side
Dichromatic filter directs light onto sample, only allows emitted wavelength to pass through to ocular

Question 4

Darkfield microscopy

Answer 4

Unstained, living cells
Darkfield condenser produces hollow cone of light (wide)
Specimen causes light rays to refract enough to enter objective
Bright objects on dark background
Only see outline detail

Question 5

Phase contrast microscopes

Answer 5

Unstained, living cells
Greater internal detail than darkfield
Difference in thickness of structures, different light waves out of phase
Positive (dark) phase contrast = dark objects on grey background

Question 6

Polarized light microscopy

Answer 6

Identification of crystals (birefringent) and fat globules in urine
Birefringent substances display colour patterns depending on orientation of two polarizing filters

Question 7

Inverted microscope

Answer 7

Tissue cell cultures, agglutination reactions in test tubes

Light source above specimen, objectives below