Lab quiz Flashcards
Why do tissues able to stain?
because of van der Waals’s forces
Who developped first microscope ?
Antonie van Leeuwenhoek
(TF) did the first microscope used below light?
no because used metal plate so examinated with natural light (or candlelight)
(TF) if a use the 20x objective lens I am looking at the 20x magnification.
False
Ocular lenses magnify 10x so total magnification is 10 x magnification of objective lens (eg 10x20=200x)
What can we use to control light source on a compound microscope?
To control light: diaphragm and condenser
What are the 4 types of tissues?
epithelial tissue
connective tissue
muscle tissue
nervous tissue
What are the steps in paraffin sectioning?
- sample collection ( appropriate thickness )
- fixation (buffered formalin, formaldehyde for hardening)
- dehydration (increase alcohol concentration to displace water out tissues)
- clearing (remove alcohol with xylol)
- infiltration ( drop tissues into warm liquid paraffin wax (get solid at RT). Paraffin allow smooth sectioning)
- sectioning (w/ microtome or blade)
What are the steps in staining paraffin section?
- remove wax with xylol
- hydration (add water to decrease alcohol concentration)
- staining (water-based stain)
- dehydration (increase alcohol concentration)
- clearing (xylol remove alcohol and extra stain)
- mounting (Permenant when between 2 glasses)
Explain most common dyes in histology, which cell is stained.
H&E use 2 stains: hematoxylin need mordant (alum) to stain nucleic acids, nuclei, RER -> blue to black
Eosin stain cytoplasm -> pink, orange,red
What can affect the color of tissues staining ?
Color Depend on: size, material, time exposure, concentration, how long wasted off, size nucleus, genetic material, nucleic acid content