Intro to Histology Flashcards
What is the difference between Histology and pathology ?
Histology is the microscopic study of normal cells and tissues while, Pathology is the microscopic study of diseased cells and tissues.
What are the 4 main tissue types?
Epithelial tissue
Connective tissue
Muscle tissue
Nervous tissue
What are the main differences between LM and EM?
Light microscopes reveal basic cellular structure its resolution is 0.2 μM
Electron microscopes can reveal ultrastructure its resolution is 1 nm (200- fold greater)
Arrange the steps for preparing a tissue sample
Viewing
Embedding
Sectioning
Fixation
Staining
Specimen collection
Dehydration
Specimen collection
Fixation
Dehydration
Embedding
Sectioning
Staining
Viewing
What type of obtaing biopsy is used for skin and oral surface?
incision or punch biopsy
Fixation
- Preserves structural arrangement between cells & ECM
- Terminates all biochemical reactions
- Prevents tissue decomposition
- Formaldehyde & Glutaraldehyde (Examples of fixatives)
What the commonly use in fixation step?
Formaldehyde and glutaraldehyde.
In Embedding step alcohol will replace by?
xylene
Sectioning step
- Sectioned using Microtome
- Thin, flat, single layer of cells sectioned (7um thick)
- Mounted onto glass slides
What are the differences between Haematoxylin and Eosin stain?
Haematoxylin is basic → stains acidic structures blue/purple (Nucleic acids)
Eosin is acidic → stains basic structures red/pink (Cytoplasm)
Periodic acid-schiff reaction (PAS) stain what?
Stains complex carbohydrates magenta
PAS-Positive → Mucins, brush borders, basement membranes
What Masson Trichrome stain and what colour will appear?
Stains connective tissues
-Nuclei & basophilic structures - blue/purple
-Collagen - green/blue
-Cytoplasm, muscle, RBC, keratin - red
What Immunohistochemistry is used for?
Utilises antibody specificity for antigen
Mention other staining protocols
Alcian Blue
– Stains mucin and cartilage blue
van Gieson
– Stains collagen red
– stains nuclei, erythrocytes and cytoplasm yellow
Reticulin stain
– Stains reticulin fibres blue/black
Which process prevents decomposition of the specimen?
Fixation