Histological Techniques

Question 1

Light Microscope

Answer 1

You can see some structure in the cell. Resolution is not as strong as TEM. Basement membrane is visible.

Question 2

Resolution

Answer 2

Measure of ability to resolve specimen. Better resolution = more detail we can resolve

(wavelength of source) x 0.61 / numerical aperture

Question 3

3 types of microscope

Answer 3

Light Microscope, Transmission Electron Microscope, Scanning Electron Microscope

Question 4

Scanning Electron Microscope

Answer 4

Focus on surface topography

Question 5

Transmission Electron Microscope

Answer 5

Best resolution microscope that can see inside organelle structures. Basal lamina is only visible at TEM level. Magnets focus a beam of electrons onto a slide

Question 6

Hematoxylin and Eosin Stain (H&E)

Answer 6

Stains the nucleus and cytoplasm respectively

Question 7

Periodic Acid Schiff (PAS stain)

Answer 7

Stains sugar residues (glycogen, glycoproteins)

Question 8

Aldehyde Fuchsin

Answer 8

Stains elastic fibers and b-cells of the pancreatic islets.

Question 9

Orecin stain

Answer 9

Stains collagen fibers and is a cytoplasmic counterstain

Question 10

Silver stain

Answer 10

Stains the Golgi and reticular fibers

Question 11

Osmium tetroxide

Answer 11

volatile and useful for staining membranes

Question 12

Epon

Answer 12

substance that is used for harding of the structures

Question 13

Fixation

Answer 13

Technique used to preserve tissue structure. Formalin (formaldehyde) is used to cross link proteins and other substances.

Question 14

Freeze fracturing

Answer 14

Used for looking at the structure in the plasma membrane

Question 15

P face

Answer 15

Protoplasmic face, internal face that makes contact with cytoplasm. Gives a look at the proteins that are imbedded in the lipid bilayers of the membranes.

Question 16

E face

Answer 16

external face, touching the exterior

Question 17

Sputter coating unit

Answer 17

A mist of gold is sprayed in order to view a slide with a SEM. It is scattered on the surface of the structure to bounce the light. Gold was found to be the best compound because of its uniformity and it can be a good mist.

Question 18

Dehydration

Answer 18

Technique used to remove water so specimen can be embedded in paraffin/plastic. Ethanol is commonly used.

Question 19

Embedding

Answer 19

Provides support for subsequent sectioning of the sample (paraffin or plastic)

Question 20

Brightfield Microscopy

Answer 20

The most common form of LM. Light shines through the specimen that is stained different colors.