PATHOLOGY- Intro to pathology Flashcards
What is pathology
The study of disease
What is histology
the study of cells and tissue by microscopy
What is histopathology
the microscopic examination of tissue in order to study the manifestations of disease
What is epidemiology
Population distribution, incidence and prevalence
What is pathogenesis
What is the mechanism that causes disease
What does primary mean in terms of disease causation
unknown cause
What does secondary mean in terms of disease causation
complication or manifestation of an underlying condition
what does primary mean in regards to stages of disease
original site of tumour development
What does secondary mean in regards to stages of disease
Secondary tumours away from the site of the primary tumour
What does the prefix ana- mean
Absence
What does the prefix dys- mean
disordered
What does the suffix -itis mean
inflammatory process
What does the suffix -entasis mean
Dilation
What are the 10 steps of tissue testing
- Extract tissue
- Fixation
- Block selection (cut up)
- Tissue processing
- Section cutting and mounting
- Section staining
- Section scanning
- Microscopy
- Diagnosis
- Prognosis prediction
What is tissue fixation
the preservation of tissues through
1. Stopping intrinsic autolytic enzyme action (autolysis)
2. Prevention of bacterial contamination (putrefaction)
3. Increasing mechanical strength to preserve structure / morphology
What is the most common tissue fixative used
Formalin (formaldehyde solution)
5 features of formalin as a tissue fixative
- Forms protein covalent cross-links
- Good penetration / mechanical strength
- Good tissue morphology preservation
- Poor nucleic acid preservation (DNA/RNA)
- Effective fixation 24-48 hours
Name 2 other fixatives
Glutaraldehyde
Ethanol
During tissue processing what must you ensure
the tissue must be resistant enough to mechanical trauma in order to slice thinly enough
Describe the steps of tissue processing before slicing
- Remove water from tissues by alcohol (dehydration)
- Replace alcohol with xylene (clearing)
- Replace xylene with paraffin wax (wax infiltration)
- Orientate tissue to form a block (embedding / blocking out)
What is the most common stain used for section staining
Haemotoxylin and eosin stain (H&E)
What does H&E do to the tissue
Haematoxylin stains acidic structures purple (e.g. nuclei)
Eosin stains basic structures pink (e.g. cytoplasm)
what can help to provide specific information with tissue testing
using antibodies against a specific target protein
What is an issue with using H&E when testing
Isn’t specific
