How To Examine Cells And Tissues Flashcards
What is the definition of tissue and what are the different types ?
Tissue is Latin for woven
E Epithelial
C connective
M muscle
N Nerve tissue
Main points on epithelial tissue
Often on edge of other tissues and surround other tissue
Sometimes clusters within tissue - glands
Polarised surfaces - apical and basal
Held together by strong anchoring proteins
Communication through junctions at later and basal surfaces
A vascular no vascularisation within them
Main points of connective tissue
Consist of cells and extracellular proteins/glycoproteins and gels
Main cells
Fibroblasts • Chondrocytes • Osteocytes/osteoblasts/osteoclasts • Stem cells/progenitor cells/bone marrow/blood/adipocytes
Main products
Fibres
Ground substance
Wax and gel-like materials
Main points one nerve tissue
Nerves can be relatively short (μm)
• Can be very long (cm)
• Main fast communication system in the body
• Cells congregate into nerve fibres
• Fibres congregate into ‘nerves’ that can be dissected
and visualised ‘by eye’
Main points on muscle tisssue
What are different ones
What are their functions
What are other functions
Cardiac, skeletal, smooth
Main function is contraction
Movement (the organism)
Stability
Movement of tissue contents
To secret hormone
What is standard measurement ?
Micron (um)
What is limit of resolution
The smallest distance by which two objects can be
separated and still be distinguishable as two separate objects.
Difference between light microscope and electron microscope.
Can see natural light / comes out monochrome
Large field of view/ limited field of view
Cheap and easy preparation / difficult and expensive preparation
Can view living and moving objects / can only see dead
Magnificat x600 and x500,000
Resolution 0.25um /0.25nm
What are the ways TEM and SEM are fixed and prepared and what one has an extra step
Fix with Glutaraldehyde
Embedded in Epoxy resin
Stain (osmium tetroxide)
Mictrome with diamond knives (TEM)
What are some tissue procurement examples
Curettage
Pipelle
Removal of whole tissue
Difference between unbuffered and buffered formalin solution?
Unbuffered only formaldehyde and water, this can lead to swelling of tissue due to osmosis
Buffered contains
NaH2PO4 and anhydrous form which soak up hydrogen if tissue to acidic and release hydrogen if too basic
What occurs after fixation?
• Dehydrated in different concentrations of alcohols • Immersed in dissolved paraffin wax (hot) overnight • Tissue orientated in a mould and more wax added • Allowed to cool to room temperature • Gently eased out of mould
What is the difference between frozen section and formalin/paraffin
Specimen (fixed or fresh)
Making time (24-48hr or 10-20minutes)
Saving time (permanent or months)
Morphology under microscopy (clarity or opacity
Application (pathological diagnosis/intraoperative consultation)
How does indirect immunohistochemsitry work
- There is a a primary antibody because it binds to the protein of interest.
- It is indirect because a secondary antibody is used to detect the first antibody
- The secondary antibody has a enzyme attached to its F.C region called Horseradish peroxidase (HRPO).
- This enzyme takes a substrate called diaminobenzadine (DAB) and converts it into coloured products.
- The coloured product is brown and precipitate where ever this product is.
How does direct immunohistochemistry work.
- In direct, the antibody still binds to its target protein.
- It has a fluorescent tag attached to the F.C region which can be excited by light and give rise to a signal.
- The light can be UV light or one generated by a laser.
