Foundations of Anatomical Pathology (W9) Flashcards
(40 cards)
what are the 3 main functions of the Anatomical pathology Laboratory
- Diagnosis - surgical pathology, cytology, morbid anatomy
- Teaching - undergraduate, postgraduate
- Research- cellular and molecular pathology, epidemiology and pathogenesis of disease
define histopathology
the microscopic examination of tissue to determine the cause of disease
- can see inflammatory-infectious disease, if something is autoimmune or acquired, and if it is benign or malignant
what are the roles of a medical scientist doing histopathology (3)
- responsible for processing tissue sample
- preparing specimen to look at under microscope
- apply techniques (chemical, technical, molecular) to permit accurate microscopic interpretation
describe the steps in routine histopathology
- specimen provided by surgical procedure
- preserve tissue (fixation) - put into formaldehyde
straight away (in surgery) - process tissue - now in lab the water is removed
- Microtomy - this section of tissue is removed
- staining
- microscopy - dictate the report/outcome
- report - then determine patient management
what are the 2 types of biopsy that can be taken for skin samples
punch biopsy - can be done by a gp to remove something small
wedge biopsy - larger area, shows where it ends
what must be done during specimen reception and dissection
- check that the name of the form is the same as on the specimen jar
- each are given a unique laboratory number and then are separated
- biopsies are transferred into cassette.
what is the universal stain
Haematoxylin and Eosin (H+E)
are all samples handled the same way
no, each sample has a specific protocol for handling it
what cells make up cytology samples
cells in body fluids, cells collected by a range of measures
what are 3 categories and some examples the hazards of working in a Histopathology Lab
- Chemical : fixatives, stains, chemicals
- Physical : sharps, radiation
- Biological : cross infection
what are some things that can be put in place as protection in an anatomical pathology lab
- appropriately dress and safety wear
- laboratory design
- alertness
- compliance with health and safety guidelines and code of conduct
- adopt prescribed procedures (to avoid clerical errors, contamination, to ensure patient safety and laboratory integrity)
ethics in Histopathology
it is required for all human investigation (discipline and research focused)
define confidentiality in histopathology
non disclosure of private health information to an unauthorised person
what is the code of conduct for histopathology
health worker are required to provide a safe, high quality, sustainable healthcare system for all of WA.
which includes:
- collaboration
- openness
- respect
- empowerment
what are 3 types of cell degradation that we want to avoid with a tissue specimen
Anoxia - restricted blood supply
Autolysis - release of lytic enzymes to self digest
Putrefaction - bacterial contamination
what are 2 type of fixation and an example of each
physical - eg. heat fixing bacteria, or microwave radiation of a tissue
chemical immersion - tissue fixation for microscopy
what are 8 outcomes from using fixation processes on a sample
(LSABICHA)
- it is permanently preserved in a life like state
- stabilizes tissue to allow for further treatment
- arrests autolysis
- prevents bacterial decomposition
- inactivates infections agents
- minimises loss of soluble cytoplasmic components
- hardens tissue
- enhanced avidity for dyes
what are 7 factors that affect fixation
- Temperature
- pH (usually best at 6-8)
- Osmolarity
- Penetration ability of fixative
- Size of specimen (small/thin)
- Concentration
- Duration
when would cold fixation be used
- if the results are needed asap (while performing a surgery)
- it is injected with liquid nitrogen
what are 6 characteristics of an ideal fixative
(EPASSC)
- economic
- preserves in a life like state
- will not add artifact material to the tissue
- will no swell or shrink tissue
- will be safe for user and environment
- convenient shelf life and storage
what are the structures in a cell that require stabilization (6)
- lipoproteins of the cell membrane
- cytoskeleton fibrous proteins
- fibrous glycoproteins
- globular proteins of the cytoplasm and extracellular fluid
- mucosubstances
- nucleic acid
what are 4 types of chemical fixatives and an example of each
- aldehydes : formaldehyde
- oxidising agents : potassium dichromate
- protein coagulants : ethanol, methanol
- uncertain mechanism : picric acid
what are the 2 common aldehydes used in fixation and what are they used for
formaldehyde - routine fixative
glutaraldehyde - electron microscopy
what are the characteristics of formalin (3)
- is it the universal fixative for anatomical pathology
- it is used at 10% v/v buffered with saline
- it is a pungent gas that is soluble in water to 40% by weight
