Lecture 3: Major Microscope Types And Staining

Question 1

What are the pros and cons of the compound light microscope?

Answer 1

It has the ability to magnify, but has a limit
Ability to resolve structural detail, but has a limit
Specimen must be thin which is difficult
Relatively little contrast in unstained specimen.

Question 2

What are the pros and cons of the phase contrast microscope

Answer 2

Allows you to examine unstained cells and tissues.
Used for living cells
Converts phase shifts into brightness changes in the image
Diff parts of the cell have small diffs in RI but the light rays are canceled out.

Question 3

Describe fluorescent microscope

Answer 3

Detects molecules that emit light of the wavelength in the visible range when exposed to UV light source.
Detects naturally occurring fluorescent molecules ex: vit A
Mostly used to detect induced fluorescence ex: antibodies, antigens, fluorescent tracers in animals or cells

Question 4

Describe a confocal microscope

Answer 4

Sharp focus onto specimen using a laser light. Mirror system allows each spot of the specimen to be recorded and stored.
Advantages: thin optical image
Out of phase images subtracted
3D images

Question 5

Transmission electron microscope

Answer 5

Uses a beam of electrons rather than light, image has to be viewed on screen.
Components: cathode, heated tungsten filaments, anode, electromagnets, specimen holder, and viewing screen and photographic film.

Question 6

What is the process of tissue prep

Answer 6

Fixing, dehydration, removal of alcohol, and embedding

Question 7

What are the components of a compound light microscope?

Answer 7

Ocular lens, objective lens, stage, condenser ( creates optimal cone of light that will pass through the objective lens) and light source.