Intro to Hist Flashcards
What are the steps involved in Microscopy?
Remember: The Fly Does Eat, Sans Mouth Villi
Tissue collection, Fixation, Dehydration, Embedding, Sectioning, Mounting and Staining, Viewing
What are 3 types of tissue collection?
Needle biopsy, Endoscopic biopsy, Other (Transvascular, Direct Excision, Curettage)
What is a cutterage biopsy?
removal of tissue by scooping or scraping, ex: endometrial lining of uterus
What is the goal of fixation and why is dehydration only relatively good at fixating?
prevent degradation + maintain architecture. Dehydrating = no fine detail
What are some common CHEMICAL fixatives?
Formaldehyde (crosslinks proteins and inactivates them) and Glutaraldehyde
What is one dehydration fixative?
OH
What can you use to rapid freeze for fixation?
Liquid isopentane OR N2
What methods/materials can be used for Embedding and sectioning?
Paraffin wax, Acrylic resin, Frozen sections
You have a sample that is 6 µm wide. What embedding material would you use?
Paraffin wax, best for 5-8 µm for light microscopy, Good resolution but slow (24 hrs)
What would you use for a 1 µm section that is to be used in high res light microscopy. What Embedding agent should you use?
Acrylic Resin, make it hard, bake it, ultrathin EM (60-80 µm), incompatible with most stains, slow!
What embedding agent is used when rapid-freezing?
Water! 12-20 µm, so low res, IDEAL for most stains, RAPID
H & E Stain?
Hematoxylin is Blue= Basic binds to Acid (cartilage matrix)
Eosin is Pink= Acidic, binds to basic regions (collagen fibers)
Massons’s trichome?
Dark Blue: Nuclei
Red: Muscle, keratin, cytoplasm
Light Blue: mucinogen, collagen
I want to view an RBC under a microscope, what should I use?
RBC is 7.6 µm, so use Light Microscope (0.25 µm)
I want to look at a human ovum, what should I use?
Human ovum is 100 µm, so use Light Microscope (0.25 µm)
I want to look at some S. Aureus. What should I use?
Staph is 1 µm, so use Light Microscope (0.25 µm)
I want to look at a virus like Polio, what should I use?
Polio is 28 nm so use Scanning Electron Microscope (SEM) (10 nm)
Histological sections are _ dimensional views of _ dimensional structures.
2, 3
What are the types of cuts of a histological section?
oblique sections, longitudinal section, cross-section
What does H & E highlight?
Hematoxylin, H, Blue, acidic, binds to cartilage matrix
Eosin, E, Pink, Basic, Collagen fibers
What do you see under scope of Connective Tissue with H & E stain?
Histiocyte (Macrophage), Blue
RBCs, Red or Pink (7.6 µm)
Collagen, Pink stringy
What do you see with blood on Wright stain?
Basophils- Red inner material
What is a Wright Stain?
Methylene Blude and Eosin, used for differential staining of blood cells.
Pink- RBCs, Eosinophil granules
Blue- Nuclei of WBCs, cytoplasm of monocytes and lymphocytes