Week 1

Question 1

Define value of histology in diagnosis.

Answer 1

E.g. Cancer
Shows what type, small cell or not?

How far it has spread.
stains ( monoclonal antibodies) very good identifying .

Imply for treatment. E.g. Lung Cancer treatment depends on whether chemo or surgery.

Question 2

Define:
Histology

Tissue

Answer 2

The study of tissues by means of specialist staining techniques combo with light and electron microscopy.

A group of cells specialised to perform a particular function.

Question 3

Describe biopsy tech:

1. Curettage
2. Needle
3. Trans vascular
4. Smear
5. Direct incision
6. Endoscopic

Answer 3

1. Sharp edged spoon. Used endometrial lining of uterus
2. All tissues by needle. Large ball needle.
3. Heart or liver. Through a major vessel and using X-ray see where using pincers to sample.
4. Scrape surface, and wipe on slide. Used to see squamous epithelial cells and to see if they have changed in nature. E.g. Cervix
5. Tube manoeuvred into lungs or intestine via anus. Probe blows air so expand side of vessel and camera and cut using pincers.
6. Any part, skin, larynx. Sample cut out.

Question 4

Fixing biopsy.

Why?

Answer 4

Formaldehyde
Glutaraldehyde

To prevent deterioration. Enzymes and lysosomes can start to break down structure.
Kills bacteria.

Macromolecules form cross links.

Question 5

Describe how shrinkage artefacts form.

Answer 5

Nike

Question 6

Stains and components

Periodic acid-schiff reaction
Haematoxylin
Eosin

Answer 6

Haemotoxylin is basic so stains acidic components purple/ blue. E.g. DNA chromatin and RNA nucleotides

Eosin is acidic so stains basic components pink.
Eg. Cytoplasmic proteins and extra cellular fibres.

Periodic acid-Schiff Reaction stains carbohydrates and glycoproteins magenta. Including mucus secreting goblet cells and basement membranes.

Question 7

Advantages of phase contrast and differential interference contrast microscopy.

Answer 7

Uses unstained cells. Useful for live cells, or cultured cells that staining may damage.

Incident light is changed as it passes through a cell but not its intensity. The microscope detects the interference effects produced when two sets of waves passed though a cell combine and is used to increase contrast of the image.

Question 8

Advantage of dark field microscopy

Answer 8

Imaged produced from scattered light. Strong light is transmitted though the specimen.

Useful in pathological work such as identifying syphilis and malaria.

Question 9

Advantages of fluorescent microscopy.

Answer 9

Monoclonal antibodies can be used to highlight many different components within one cell.
E.g. One will highlight actin filaments, metaphase chromosomes and micro tubules. Producing three micrographs.

Very specific components can be stained.

Question 10

Confocal microscopy advantages

Answer 10

Used to image tissues labels with more than on fluorescent probes.
Doesn’t have interference with resolution of structures in focus that light microscopy does. Eliminates out of focus flare from thick fluorescent lullabies specimens.
Non invasive
Used for live specimens
Can produced 3D images