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Flashcards in Intro to pathology Deck (60)
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1
Q

What is disease?

A

Consequence of failed homeostasis
Gives morphological and functional disturbances
Lead to an identifiable group of symptoms and signs

2
Q

What causes disease?

A

Intrinsic abnormalities
e.g. genetic mutations

External factors
e.g. microbial infection

3
Q

What is pathology?

A

Study of disease and cellular dysfunction

4
Q

What are the pathology disciplines?

A

Chemical pathology
study disturbances of metabolic processes

Haematology
study disturbances of cellular and coagulable components

Cellular pathology

Immunology
study of diseases of immune system

Microbiology
study of infectious diseases

5
Q

What is cellular pathology?

A

The macroscopic and microscopic assessment of cells, tissues, organs

6
Q

What is histopathology?

A

Looking at sections of tissue under a microscope

7
Q

What are some examples of tissue sections looked at in histopathology?

A

Core biopsy
Cancer resection specimen
Excised skin lesion

8
Q

What is cytopathology?

A

Cells are scraped off, sucked out
From lesion, organ, body fluid
Cells are disaggregated
Looked at under microscope

9
Q

What are the advantages of histopathology?

A

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.

10
Q

What are the advantages of cytopathology?

A

Faster

Cheaper

Minimally invasive, safe

Can be used for cells in fluids

11
Q

What are the disadvantages of cytopathology?

A

Higher inadequate errors

Error rates

12
Q

What are some examples of specimens looked at in cytopathology?

A

Fine needle aspirates of breast, thyroid, lungs

Effusions

Sputum, urine

Cervical smears

13
Q

What is neuropathology?

A

Cellular pathology

confined to brain, spinal cord, nerves, muscle

14
Q

What is forensic pathology?

A

Medicolegal investigation of suspicious or criminal deaths

15
Q

What are the uses of cytopathology?

A

Useful to confirm/exclude
cancer/dysplasia
before making other diagnoses

16
Q

What is paediatric pathology?

A

Examine samples from children

17
Q

What are the stages involved to prepare a slide in microscopy?

A
fixation
cut up
embedding
blocking
microtomy
staining
mounting
18
Q

What is fixation?

A

Keep tissue in formalin solution

for 24-48 hours

19
Q

What is the purpose of fixation?

A

To block tissue autolysis
by inactivating enzymes, denaturing proteins

Also to prevent bacterial growth

And to harden the tissue

20
Q

Why does tissue autolysis occur?

A

Lack of blood supply to tissue

21
Q

What does tissue autolysis result in?

A

Loss of cellular architecture

22
Q

What is cutting up?

A
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
23
Q

What is embedding?

A

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

24
Q

What is the purpose of embedding?

A

To harden the tissue

so it can be cut into thin slices

25
Q

What is blocking?

A
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
26
Q

What is microtomy?

A

Use microtome to cut thin sections from block
floated on water bath
picked up on microscope slide

27
Q

What is the purpose of microtomy?

A

Cut tissue into thin sections

so can see through them with microscope

28
Q

What is staining?

A

Use haematoxylin + eosin
haematoxylin stains nulcei purple
eosin stains cytoplasm and connective tissue pink

29
Q

What is the purpose of staining?

A

To allow the tissue to be seen under the microscope

30
Q

What is mounting?

A

Apply mounting medium to slide
put coverslip on top
mounting medium dries, hardens
attaching tissue to coverslip

31
Q

What is the purpose of mounting?

A

To preserve and protect the tissue
preserved by hardening
protected by attaching to coverslip

32
Q

What are the uses of microscopy?

A

To give a definite diagnosis

Show that surgery is required
guide the type and extent of surgery

To reason for alternative treatment, not surgery
e.g. chemotherapy, antibiotics, palliative care

May show that no treatment is required

33
Q

How is histopathology used in cancer management?

A
Diagnosis of cancer
Benign or malignant
Primary or metastasis
Grade of cancer
Stage of cancer
Involvement of margins
Completeness of excision
Efficacy of treatments
34
Q

How does immunohistochemistry work?

A

Antigenic substance in or on cells
label it with antibodies
antibodies joined to an enzyme e.g peroxidase
catalyses a colour changing reaction

35
Q

How does immunohistochemistry indicate the antigenic substance is present?

A

Colour change

Usually to a brown colour

36
Q

What antigenic substances can be used in immunohistochemistry?

A

Actin

Cadherins

Hormone receptors e.g. oestrogen, progesterone

Her2 receptor

Micro-organisms e.g CMV, HPV, herpes simplex

Cytokeratins

37
Q

What us the use of identifying actin?

A

To identify smooth muscle cells

38
Q

What are cadherins?

A

Cell adhesion molcules

39
Q

What is the use of identifying cadherins in cancer?

A

Deficient in some cancers e.g. lobular breast cancer
present in others
help to tell the type of cancer

40
Q

What is the use of identifying oestrogen and progesterone hormone receptors in breast cancer?

A

Give idea of how patient will respond to specific treatments

41
Q

What is the her2 receptor?

A

A growth factor receptor

42
Q

What is the use of identifying her2 receptors in breast cancer?

A

If present in breast cancer

means will likely respond anti-her2 treatment

43
Q

What is an example of an anti-her2 drug?

A

Herceptin

44
Q

What are cytokeratins?

A

Intracellular
fibrous proteins
present in all epithelial cells
different types are present in different tissues

45
Q

What is the use of identifying cytokeratins in cancer?

A

If present, means the cancer is epithelial in origin, in other words a carcinoma

CK7+ CK20- indicates lungs, thyroid, breast, endometrium, ovary

CK7- CK20+ indicates large bowel, some gastic carcinomas

46
Q

What is molecular pathology?

A

Study of disease caused by altered DNA, RNA, proteins

47
Q

What is meant by in situ molecular tests?

A

Looking for alterations in DNA in tissues prepared for microscopy

48
Q

What is an example of an in situ molecular test?

A

FISH

49
Q

What are the uses of FISH?

A

Can tell if a gene has been copied
deleted
translocated
if any viral genes are present

50
Q

What is the use of FISH in breast cancer?

A

Looking at her2 gene

If there are extra copies of it

51
Q

What is the significance of extra copies of the her2 gene in breast cancer cells?

A

Means are producing more growth factor

more affected by anti-her2 treatment e.g. herceptin

52
Q

What is the use of DNA sequencing?

A

Show is a particular point mutation is present in a gene

53
Q

What is the use of DNA sequencing in lung cancer?

A

Certain point mutations in EGFR gene

means cancer is likely to respond well to anti-EGFR treatment

54
Q

What is an example of an anti-EGFR drug?

A

Erlotinib

55
Q

What is the use mRNA expression profiling?

A

Gives an idea of how active genes area

56
Q

What is the use of mRNA expression profiling with cancer?

A

Predicts behaviour of cancer
To do with spread
recurrence

57
Q

When is a frozen section used?

A
Intra-operation
Lesion identified
Need to establish its nature
e.g. inflammatory mass or neoplasm?
Will affect the course of the surgery 
e.g. whether should resect it or not
Have to be quick
while patient is still under anasthetic
58
Q

What is the process involved in using a frozen section?

A
Fresh tissue
cut it into small pieces
freeze it using a cryostat
slice it thinly using microtome
stain it
mount it
59
Q

What are the disadvantages of a frozen section?

A

May give incorrect diagnosis
false negative

Because cellular morphology is harder to interpret
Lesion of interest may not be in tissue submitted for frozen section

60
Q

What information is included in the final report?

A

History

Macroscopic appearance

Micropscopic appearance

Conclusion