Introduction to Microscopy and Histology

Question 1

Who coined the word “cell” ?

Answer 1

Robert Hooke (50x mag)

Question 2

Used microscope for life in water drop (protist), bacterium, spermatozoa, and circulation in blood

Answer 2

Leeuwenhoek (270X)

Question 3

What is a light microscopy?

Answer 3

pass light through a specimen and this type of microscope is able to use both magnification and resolution to see the object under light

Question 4

what is resolution?

Answer 4

allows you to see two close but distinct points

Question 5

What are the steps for tissue imaging?

Answer 5

1. fixation
2. dehydration
3. embedding
4. sectioning
5. rehydrate
6. staining

Question 6

When would you use the cyroalternative?

Answer 6

when you need to see the tissue immediately or need it for immunoflourance techniques EX: blood, bone marrow, epithelial cells

Question 7

What are the steps for cyro- alternative staining?

Answer 7

1. no dehydration
2. embedding with gelatin or OCT
3. deep freeze (isopentane or liquid nitrogen)
4. sectioning with cryostat
5. remove gelatin/ OCT
6. staining

Question 8

What is the purpose of rapid freezing?

Answer 8

prevents ice crystals, preserve cell strict, prevents damage

Question 9

what are cytosections good fro?

Answer 9

detecting antigens

Question 10

Frozen section are good for what?

Answer 10

immunochemistry, and enzymatic detection

Question 11

What are cell smears?

Answer 11

things like bone marrow, blood, or epithelial cells are not sectioned, fixed in alcohol and stained right away

Question 12

hematoxylin

Answer 12

basic dye that stains acidic components blue EX; nuclei , ribosome, RNA

Question 13

eosin

Answer 13

acidic dye that stains basic components red-pink EX: proteins, collagen

Question 14

Which dye would you use to look at mitotically active cells?

Answer 14

hematoxylin

Question 15

Periodic acid-Schiff (PAS) staining?

Answer 15

pink, magenta used to stain carbohydrates

Question 16

orcein

Answer 16

dark brown purple color, stain electric fibers

Question 17

osmium tetroxide

Answer 17

stains lipids and myelin a dark brown color

Question 18

Oil Red O

Answer 18

stains lipids red-orange in unfixed frozen sections

Question 19

toluidine blue

Answer 19

high affinity for acidic busses. staines nucleic acid blue and polysaccharides purple. great for chromosome staining

Question 20

metal impregnation

Answer 20

silver is commonly used, to demonstrate reticular fibers

Question 21

Nissl Stain

Answer 21

selective staining developed by Nissl using an aniline stain to label extra-nuclear RNA granules- good for visualizing Rough ER

Question 22

what is vital staining?

Answer 22

uptake of dyes by cells

Question 23

trypan blue

Answer 23

identifies dead cells

engulfed by macrophage and can be used to delineate kipper cells of the liver

Question 24

wright/glemsa stain

Answer 24

attach to DNA

used to stain blood, bone barrow, parasites

Question 25

neutral red

Answer 25

in lysosome of liver cells.

red when protonated and colorless when unprotonated/permeable

Question 26

janus green

Answer 26

changes color with different amounts of oxygen

• green= oxidized, in mitochondria
• colorless before

Question 27

IHC

Answer 27

detection of antigen with antibodies in the tissue

Question 28

ICC

Answer 28

detection og antigen with antibodies in isolated or intact cells

Question 29

Facts about transmission electron microscope (TEM)

Answer 29

• passes electron through specimen
• focused by magnetic lens
• image is on fluorescent screen
• magnification=10,000,000X
• resolves .2nm object

Question 30

Facts of scanning electron microscope (SEM)

Answer 30

• elections passed round specimen
• 1nm resolution
• 150,000X magnification
• detailed image of surface