Fundamentals of histology Flashcards
What are neutrophils a marker of?
- > marker of ACUTE inflammation i.e. Appendicitis
- > Features a multilobed nuclei and granules
What are lymphocytes a marker of?
- > Typically a marker of Chronic Inflammation i.e. Chronic H.Pylori Gastritis
- > Features a large nucleus with a small amount of cytoplasm
- May be a marker of a malignant process i.e. Sheets of Lymphocytes = Lymphoma, Sheets of Plasma Cells = Multiple Myeloma.
- *Many diseases may have a mixture of both acute and chronic inflammation i.e. Lymphocytes&Neutrophils
What are Eosinophils a marker of?
- > Markers of Allergic reaction, parasitic infection and tumours (i.e. asthma, drug hypersensitivity, schistosomiasis, Hodgkin’s)
- > Features a bilobed nuclei with red granules
What are Mast cells a marker of?
- > Markers of Urticarial reactions
- > Features large cells with multiple granules
What are macrophages a marker of?
A macrophage in its natural state is phagocytic but in chronic inflammatory conditions they become secretory
Markers of
- Late acute inflammation, “brainless cells that come at the end of the party to clean out the rubbish”
- Chronic Inflammation, develop more cytoplasm and look like epithelial cells i.e. activated secretory epithelioid
What is a Squamous Cell Carcinoma?
- > These can originate from any site of squamous cells i.e. skin, head and neck, oesophagus, anus, cervix and vagina
- > Feature intercellular bridges between cells, and some cells produce keratin pearls
What is an adenocarcinoma?
- > These are tumours of the glands and can arise from lung, breast, stomach, colon, pancreas, sweat glands
- > Feature glandular formation and the release of Mucin
What is a melanoma?
`-> Tumours of melanin producing skin
-> Fontana staining identifies melanin
What is a histochemical stain?
This is where the stain is based on a chemical reaction between the stain and a specific component of the tissue, examples include
- > Haematoxylin and Eosin, everyday stain of choice which binds to the acidic and basic part of tissue. MOST COMMON.
- > Prussian blue iron stain, check for iron overload (haemochromatosis) of tissue
- > Congo red stain, check for amyloid, apple green birefringence when viewed under polarised light
What is an immunohistochemical stain?
This is where either enzyme-substrate reactions (Immunoperoxidase) or antibody-antigen reactions can identify the properties of the stained material.
- > Cytokeratin - present on all epithelial cells
- > CD45 - acts as a lymphoid marker
- > HSV1 antiobodies - can identify which subtype of HSV has infected the patient
What is feline oesophagus?
Eosinophilic Oesophagitis is characterised by horizontal striae across the oesophagus
What is a granuloma?
A granuloma is an organised collection of macrophages that have turned into secretory epithelioid and found in granulomatous conditions i.e. TB, Leprosy, Fungal Infections and Sarcoid.
- > If this is caseous, you will see cheesy yellow areas.
- > The fusion of secretory epithelioid macrophages leads to the development of Langerhans Giant Cells (ring shaped structure with horse shoe nuclei).
