Microscopy Flashcards
Define the term “tissue”
A collection of cells specialised for a particular function
Define the term “organ”
An aggregation of tissues
Why is biopsy important?
It is the final proof for most diseases e.g lung/breast cancer
Why is it difficult to study fresh biopsies?
They are wet and bloody
What does it mean for a tissue to be fixed?
Macromolecules cross linked, cellular structure preserved, no autolysis (destruction of cells by own enzymes) or putrefaction (rotting)
What are the two common fixatives?
Glutaraldehyde and formaldehyde
How do haemotoxylin and eosin work as staining agents?
Haemotoxylin- stains acidic components purple/blue
Eosin- stains basic components pink
How does the periodic-acid schiff stain work?
Stains glycoproteins and polysaccharides magenta
What does the term ‘limit of resolution’ mean?
Smallest distance between two points on a specimen that can be distinguished as seperate entities
What is the size of most cells?
10-20 um
Describe the smear biopsy
cells collected by spontaneous/mechanical exfoliation
For which tissues, is the smear technique used?
Cervix, buccal cavity
Describe the curettage biopsy
tissue removed by scooping/scraping
For which tissues is curettage biopsy used?
endometrial uterus lining
For which tissues is needle biopsy used?
brain, breast, liver, kidney, muscle
For which tissues is direct incision used?
Skin, mouth, larnyx
For which tissues is endoscopy used?
lungs, intestine, bladder
For which tissues is transvascular biopsy used?
heart, liver
Describe phase contrast microscopy
uses interference effects of two combining light waves
What is a benefit of phase contrast microscopy?
Images of unstained cells are enhanced
Describe dark field microscopy
Excludes unscattered beams, either light or electrons, from the image
What is the benefit of dark field microscopy?
It can be used on both live and unstained samples
Describe fluorescence microscopy
Molecules targeted with fluorescent stains
What is a benefit of fluorescence microscopy?
Multiple fluorescent stains can be used on one sample
Describe confocal microscopy?
increases optical resolution and contrast of a micrograph
What are the benefits of confocal microscopy?
“Out of focus” flare eliminated, 3D image can be produced, live tissue can be studied
