histology Flashcards
patholgy
study of diseases
cytology
study of microscopic features of normal cells
cytopathology
study of cells with disease
histology
study of microscopic features of normal tissue
histopathology
study of tissue with disease
What are the steps from specimen to report?
1) fixation
2) specimen collection / transportation / receipt
3) tissue selection + description
4) tissue processing
5) tissue embedding
6) microtomy
7) staining + mounting
8) quality assurance
9) reporting
10) specimen disposal
11) block + slide archiving
fixation
process of preserving cells
ischaemia
restriction in blood supply to tissues, causing shortage of oxygen + food, and build up of waste
autolysis
uncontrolled release of intracellular enzymes from lysosomes
putrefaction
action of microorganisms that produces gases
How is prevention of cellular deterioration done?
1) fixing
2) freezing
What factors affect the rate of fixation?
1) temperature
2) size of specimen + penetration of fixative
3) volume
4) pH + buffers
5) osmolarity
6) concentration
7) duration
What are the 2 main types of histopathological specimens?
1) biopsy
2) surgical specimen
histological sample
solid tissue
cytological samples
isolated cells
What methods are used for sample collection?
1) incision
2) resection
3) brush cytology
4) needle core biopsy
5) US guided fine needle aspirate
6) excisional biopsy
What methods are used for sampling of skin?
1) excisional biopsy
2) incisional biopsy
3) shave biopsy
4) punch biopsy
excisional biopsy
complete lesion removed with margin of normal skin down to adipose tissue
incisional biopsy
cross-section wedge of tissue through centre of lesion
shave biopsy
horizontal shave of skin lesion with only superficial portion of dermis
punch biopsy
sampling of cancers / tumors / inflammatory skin conditions
What method of fixation is used for histological examination?
neutral buffered formalin
What method of fixation is used for cytological examination?
alcohol fixatives
What strength of formaldehyde is used for routine fixation?
4%
macroscopic description of the specimen
description that includes gross appearance / measurements / details of blocks taken
Who makes histopathological diagnosis?
pathologist
Who tests patients samples?
biomedical scientist
H&E
haematoxylin + eosin
What colour is cytoplasm + nuclei with H&E?
1) cytoplasm = pink
2) nuclei = purple
How thick is simple epithelium tissue?
one cell thick