Examining cells

Question 1

Define limits of resolution

Answer 1

The smallest possible distant by which 2 objects can be seen as distinct

Question 2

What does haematoxylin stain and what colour

Answer 2

Acids into purple

Question 3

What are the 3 steps in preparing a sample

Answer 3

• Fixation
• Staining
• Embedding

Question 4

What is used to fix samples and why is this process done

Answer 4

Formalin

Used to prevent putrification

Question 5

What is commonly used to embed samples and why is this done

Answer 5

Paraffin

To be able to cut the sample into thin slices

Question 6

Why is fat not seen when tissues are embedded

Answer 6

Because the alcohol washes used to dehydrate the samples strip it of fat

Question 7

What does eosin stain and what colour

Answer 7

Proteins

Pink

Question 8

Describe curettage and give an example of a tissue can be sampled

Answer 8

Use of a curette to scrap out a sample

Uses to sample endometrial epithelium

Question 9

What fixative is commonly used to stain cells that are carbohydrate rich

Answer 9

Periodic Acid-Schaffer’s stain

Question 10

What stain is commonly used to distinguish cells from surrounding connective tissue

Answer 10

Masson’s Trichrome

Question 11

What are the benefits of frozen sections

Answer 11

• Able to use fresh tissues
• Samples only saved for months
• Able to be made in minutes

Question 12

Describe immunohistochemistry

Answer 12

Use of antibodies to bind to antigens on cells

Question 13

What needs to be constant in the internal environment when preparing live cultures

Answer 13

Same pH
Conc. of O2, CO2
Temperature

Question 14

What are the advantages of using a live cell culture

Answer 14

• Sample is homogenous

- Absolute control of the physical environment

Question 15

What are the disadvantages of using a cell culture

Answer 15

• Hard to maintain
• Cells are able to differentiate
• Expensive
• 3 dimensional structure is lost