Examining Cells and Tissues Flashcards
What is the difference between milli,micro and nano?
- milli (m) = 10-3
- micro = 10-6
- nano (n) = 10-9
Define tissue
Groups of cells that act together to perform a specific function
What is the value of histology in diagnosis?
Enables close examination of a tissue’s composition that can help determine appropriate treatment
Define ‘Limit of Resolution’
The smallest distance by which 2 objects can be distinguished as 2 objects
State 3 biopsy techniques and the tissues they can sample
Curettage - endometrial tissue
Venepuncture - blood smear
Aspiration - bone marrow
Why does tissue need to be fixed and what is used to fix it?
- To preserve the sample
- Formalin
What is used to embed a tissue and why is this needed?
Paraffin wax
Allows a very thin slice to be taken for examination
What is the value of histological staining?
Allows cell ultrastructure and organelles to be seen
State the components of tissues stained by routine stains
Haematoxylin - Stains DNA/RNA (nucleus)
Eosin - Stains cytoplasm and extracellular matrix
How does immunohistochemistry and immunofluorescence achieved?
Monoclonal antibodies are used to bind to specific proteins and localise specific cell and tissue targets
What are 4
Light Microscopy variants?
Phase Contrast - Converts phase shifts in light into brightness changes
Dark Field - Unattenuated light is not collected by the objective lens
Fluorescence - Highlights a specific target
Confocal Microscopy - Takes multiple 2D images to reconstruct a 3D image
Why are electron microscopes capable of higher definition than light microscopes?
Using a beam of electrons means higher resolution and magnification but it is more expensive
What are the 2 types of electron microscopy and what is the difference between them?
Transmission Electron Microscopy
- Electrons transmitted through specimen
- 2D
Scanning Electron Microscopy
- Electrons reflected off specimen surface
- 3D
