Flashcards in Intro to pathology Deck (60)
What is disease?
Consequence of failed homeostasis
Gives morphological and functional disturbances
Lead to an identifiable group of symptoms and signs
What causes disease?
e.g. genetic mutations
e.g. microbial infection
What is pathology?
Study of disease and cellular dysfunction
What are the pathology disciplines?
study disturbances of metabolic processes
study disturbances of cellular and coagulable components
study of diseases of immune system
study of infectious diseases
What is cellular pathology?
The macroscopic and microscopic assessment of cells, tissues, organs
What is histopathology?
Looking at sections of tissue under a microscope
What are some examples of tissue sections looked at in histopathology?
Cancer resection specimen
Excised skin lesion
What is cytopathology?
Cells are scraped off, sucked out
From lesion, organ, body fluid
Cells are disaggregated
Looked at under microscope
What are the advantages of histopathology?
Can assess cellular architecture
Can differentiate in situ from invasive disease
Can provide info on grade of tumour, stage of tumour, completeness of excision
Is therapeutic as well as diagnostic, because are removing lesion, cancerous cells etc.
What are the advantages of cytopathology?
Minimally invasive, safe
Can be used for cells in fluids
What are the disadvantages of cytopathology?
Higher inadequate errors
What are some examples of specimens looked at in cytopathology?
Fine needle aspirates of breast, thyroid, lungs
What is neuropathology?
confined to brain, spinal cord, nerves, muscle
What is forensic pathology?
Medicolegal investigation of suspicious or criminal deaths
What are the uses of cytopathology?
Useful to confirm/exclude
before making other diagnoses
What is paediatric pathology?
Examine samples from children
What are the stages involved to prepare a slide in microscopy?
What is fixation?
Keep tissue in formalin solution
for 24-48 hours
What is the purpose of fixation?
To block tissue autolysis
by inactivating enzymes, denaturing proteins
Also to prevent bacterial growth
And to harden the tissue
Why does tissue autolysis occur?
Lack of blood supply to tissue
What does tissue autolysis result in?
Loss of cellular architecture
What is cutting up?
Tissue is cut up into small pieces
put into a cassette
has holes in the lid
put into racks of formalin
holes allow formalin to enter and bathe tissue
What is embedding?
Remove water from tissue using alcohol in a vaccuum
replace alcohol with xylene, because xylene mixes with wax
replace xylene with molten paraffin wax
will penetrate cells
What is the purpose of embedding?
To harden the tissue
so it can be cut into thin slices
What is blocking?
Take tissue out of casette
put into metal block
fill with paraffin wax
body of cassette placed on top
wax allowed to harden
metal tray removed
What is microtomy?
Use microtome to cut thin sections from block
floated on water bath
picked up on microscope slide
What is the purpose of microtomy?
Cut tissue into thin sections
so can see through them with microscope
What is staining?
Use haematoxylin + eosin
haematoxylin stains nulcei purple
eosin stains cytoplasm and connective tissue pink
What is the purpose of staining?
To allow the tissue to be seen under the microscope