Hair and fibre examination

Question 1

What is the active hair growth phase?

Answer 1

Angen

Question 2

What is the catagen phase of hair growth?

Answer 2

When the follicle begins to shut down production of cells and root condenses into bulb shape

Question 3

What is the telogen phase of hair growth?

Answer 3

Cell production has ceased completely

Question 4

If follicle tissues are present on a removed hair, what phase was it most likely in?

Answer 4

Anagen or catagen

Question 5

What is the purpose of hair analysis in identification?

Answer 5

Can provide an estimate on ethnicity or ancestry

Question 6

How are hairs compared?

Answer 6

Using a comparison microscope examining from root to tip but only providing a suggestion two hair could come from the same source

Question 7

What are delustrants in fibre analysis?

Answer 7

Finely ground material such as titanium oxide that reduces the sheen of the fibre to assist in analysing light diffraction

Question 8

What feature of the Becke line indicates the fibre has a high refractive index?

Answer 8

Lowering the stage moves the Becke line towards the fibre, away from the medium

Question 9

What feature of the Becke line indicates the fibre has a low refractive index?

Answer 9

Lowering the stage moves the Becke line away from the fibre, towards the medium

Question 10

What is the difference between dyes and pigments?

Answer 10

Dyes absorb to the fibre and reflect certain wavelengths of light while pigments are bonded to the fibre surface by a resin

Question 11

What chemical methods are used to analyse fibre?

Answer 11

Thin layer chromatography to characterise the dye

Question 12

What is the purpose of microspectrophotometer in fibre analysis?

Answer 12

Compares the amount of light passing through the air with the amount of light transmitted off the sample, giving a percentage of light transmitted or absorbed