Hair

Question 1

why is hair a good form of trace evidence

Answer 1

easily over looked, readily transferred, highly stable, persistent
can use ratios of elements present to tell where someone has been
links to substances of abuse

Question 2

Lanugo vs vellus

Answer 2

lanugo = formed in utero, typically shed
vellus = fine short, unpigmented found on all skin surfaces except palms and soles

Question 3

primary/ secondary/ terminal hairs

Answer 3

primary - head, eyelashes, eyebrow
secondary - pubic, underarm, beard
terminal - macroscopically visible

Question 4

the cuticle

Answer 4

outermost layer, responsible for chemical resistance
Features: colour, thickness, damage, scale protrusions

Question 5

the cortex

Answer 5

main bulk of hair, responsible for mechanical properties, contains pigment granules
Features: texture, pigment distribution, size and shape

Question 6

the medulla

Answer 6

inner most layer, not present in all hairs
features: appearance of medulla, growth stage of root

Question 7

the hair growth cycle

Answer 7

1. Anogen - active growth (85-90% of all head hairs)
2. Catagen - transition phase, growth stops
3. Telogen - resting phase, follicle closes, shedding begins (10-15% of all head hairs)

Question 8

analytical workflow for hairs

Answer 8

gross examination
physical characteristics
microscopic techniques
SEM
spectroscopic techniques
chromatographic and MS

Question 9

mass spectrometry
ionisation methods
mass analysers

Answer 9

produces ions from a compound in order to obtain molecular weight and structural info because only charged species are detected

Ionisation methods: Electrospray, desorption electrospray, laser desorption electrospray

Mass analysers: Quadrupole, TOF, magnetic sectors

Question 10

information in hair reference collections

Answer 10

• ancestral groups
• cosmetic treatments
• locations of body
• damaged and degraded types