Microscopy

Question 1

Define the term “tissue”

Answer 1

A collection of cells specialised for a particular function

Question 2

Define the term “organ”

Answer 2

An aggregation of tissues

Question 3

Why is biopsy important?

Answer 3

It is the final proof for most diseases e.g lung/breast cancer

Question 4

Why is it difficult to study fresh biopsies?

Answer 4

They are wet and bloody

Question 5

What does it mean for a tissue to be fixed?

Answer 5

Macromolecules cross linked, cellular structure preserved, no autolysis (destruction of cells by own enzymes) or putrefaction (rotting)

Question 6

What are the two common fixatives?

Answer 6

Glutaraldehyde and formaldehyde

Question 7

How do haemotoxylin and eosin work as staining agents?

Answer 7

Haemotoxylin- stains acidic components purple/blue

Eosin- stains basic components pink

Question 8

How does the periodic-acid schiff stain work?

Answer 8

Stains glycoproteins and polysaccharides magenta

Question 9

What does the term ‘limit of resolution’ mean?

Answer 9

Smallest distance between two points on a specimen that can be distinguished as seperate entities

Question 10

What is the size of most cells?

Answer 10

10-20 um

Question 11

Describe the smear biopsy

Answer 11

cells collected by spontaneous/mechanical exfoliation

Question 12

For which tissues, is the smear technique used?

Answer 12

Cervix, buccal cavity

Question 13

Describe the curettage biopsy

Answer 13

tissue removed by scooping/scraping

Question 14

For which tissues is curettage biopsy used?

Answer 14

endometrial uterus lining

Question 15

For which tissues is needle biopsy used?

Answer 15

brain, breast, liver, kidney, muscle

Question 16

For which tissues is direct incision used?

Answer 16

Skin, mouth, larnyx

Question 17

For which tissues is endoscopy used?

Answer 17

lungs, intestine, bladder

Question 18

For which tissues is transvascular biopsy used?

Answer 18

heart, liver

Question 19

Describe phase contrast microscopy

Answer 19

uses interference effects of two combining light waves

Question 20

What is a benefit of phase contrast microscopy?

Answer 20

Images of unstained cells are enhanced

Question 21

Describe dark field microscopy

Answer 21

Excludes unscattered beams, either light or electrons, from the image

Question 22

What is the benefit of dark field microscopy?

Answer 22

It can be used on both live and unstained samples

Question 23

Describe fluorescence microscopy

Answer 23

Molecules targeted with fluorescent stains

Question 24

What is a benefit of fluorescence microscopy?

Answer 24

Multiple fluorescent stains can be used on one sample

Question 25

Describe confocal microscopy?

Answer 25

increases optical resolution and contrast of a micrograph

Question 26

What are the benefits of confocal microscopy?

Answer 26

“Out of focus” flare eliminated, 3D image can be produced, live tissue can be studied