Lab quiz

Question 1

Why do tissues able to stain?

Answer 1

because of van der Waals’s forces

Question 2

Who developped first microscope ?

Answer 2

Antonie van Leeuwenhoek

Question 3

(TF) did the first microscope used below light?

Answer 3

no because used metal plate so examinated with natural light (or candlelight)

Question 4

(TF) if a use the 20x objective lens I am looking at the 20x magnification.

Answer 4

False
Ocular lenses magnify 10x so total magnification is 10 x magnification of objective lens (eg 10x20=200x)

Question 5

What can we use to control light source on a compound microscope?

Answer 5

To control light: diaphragm and condenser

Question 6

What are the 4 types of tissues?

Answer 6

epithelial tissue
connective tissue
muscle tissue
nervous tissue

Question 7

What are the steps in paraffin sectioning?

Answer 7

1. sample collection ( appropriate thickness )
2. fixation (buffered formalin, formaldehyde for hardening)
3. dehydration (increase alcohol concentration to displace water out tissues)
4. clearing (remove alcohol with xylol)
5. infiltration ( drop tissues into warm liquid paraffin wax (get solid at RT). Paraffin allow smooth sectioning)
6. sectioning (w/ microtome or blade)

Question 8

What are the steps in staining paraffin section?

Answer 8

1. remove wax with xylol
2. hydration (add water to decrease alcohol concentration)
3. staining (water-based stain)
4. dehydration (increase alcohol concentration)
5. clearing (xylol remove alcohol and extra stain)
6. mounting (Permenant when between 2 glasses)

Question 9

Explain most common dyes in histology, which cell is stained.

Answer 9

H&E use 2 stains: hematoxylin need mordant (alum) to stain nucleic acids, nuclei, RER -> blue to black
Eosin stain cytoplasm -> pink, orange,red

Question 10

What can affect the color of tissues staining ?

Answer 10

Color Depend on: size, material, time exposure, concentration, how long wasted off, size nucleus, genetic material, nucleic acid content