Introduction to Histology Flashcards
What are transvascular biopsies used on?
- Heart
- Liver
Vascular = Blood flow, organs that have a lot of blood flowing through them
What are the 7 steps of microscopy?
- Tissue collection
- Fixation
- Dehydration and clearing
- Embedding
- Sectioning
- Mounting and staining
- Viewing
What are direct excision biopsies used on?
- Skin
- Larynx
- Uterine cervix
- Mouth
SLUM
What is the curettage biopsy used on?
- Endometrial lining of uterus (scraping)
Where is the endoscopic biopsy used?
- Respiratory tract
- Allmentary tract
- Urinary tract
Before endoscope you ask, Are(Allementary) You(Urinary) Ready(Respiratory)?
What is the goal of fixation?
To preserve tissues by preventing degradation while maintaining normal tissue architecture.
What are the three common fixative types?
- Chemical fixatives
- Dehydration
- Rapid freezing
Why would you use glutaraldehyde over formaldehyde?
Glutaraldehyde is a stronger fixative and must be used for the slide to be compatible with an electron microscope.
GEM:
Glutaraldehyde
Electron
Microscope
What are the three ways to embed and section?
- Paraffin wax
- Acrylic resin
- Frozen sections
FAP
Paraffin Wax:
Thickness of slide?
Resolution?
Time?
- 5-8 um for light microscopy
- Good resolution of cell structure and tissue architecture
- Slow, 24 hours
Acrylic Resin
- Thickness and microscopy type? (2)
- Incompatible with _________.
- Time?
- 1 um for high resolution light microscopy
- 60 - 80 nm for EM
- Histological stains
- Slow, several days
Frozen sections
Thickness and visualization?
Ideal for ________ and __________ stains.
Time?
- Thick (12 - 20 um)m relatively low resolution
- Histochemical and immunological
- Rapid (minutes - hours)
What is the hematoxylin stain used for? *
- Acidic structures in cell
- Cartilage matrix
HAC
What is the eosin stain used for?
- Basic regions of cytoplasm
- Collagen fibers
What is the Masson’s trichrome stain used for?
- Nuclei
- Muscle, keratin, cytoplasm
- Mucinogen, collagen
What is Weiget’s elastic stain for?
- Elastic fibers
What is the silver stain used for?
- Neurofilaments
- Reticular fibers
Silver is expensive and valuable. Neuro = brain, your brain is valuable.
What is iron hematoxylin used to stain?
- Striations of muscle
- Nuclei
- Erythrocytes
Iron is in blood, erythrocytes in blood.
Need iron for muscles.
What is the periodic acid-schiff stain used for? *
- Glycogen and carbohydrate rich molecules
What is the Wright stain used to stain? *
- Used for differential staining of blood cells.
- Pink = erythrocytes
- Blue = nuclei of white blood cells, cytoplasm of monocytes and lymphocytes
Resolution of: Human eye? Light microcope? Transmission electron microscope? Scanning electron microscope?
- 0.1 - 0.2 mm
- 0.25 um
- 0.2 nm
- 10 nm
What is resolving power?
The ability of something to distinguish between two points as the two points come closer. This is the most important part of the microscope.
What is autoradiography?
The incorporation of radioactive isotopes into macromolecules, which are then visualized by use of an overlay of film emulsion.
Black dots/ silver stains
What is an enzyme histochemistry stain?
Cleavage of artificial substrate results in deposition of insoluble colored reaction product at site of enzyme activity.
Lots of dark dots.
