AIM: How is hair analyzed in forensics?Do Now: A single scalp hair approximately 14 inches long was found on a female victim of African descent who lives alone. The hair had a low distribution of phenomelanin in the cortex, a slightly oval cross section, and a medulla that was fragmented. What might the person that police wish to question look like?

HW: complete questions on back of hair analysis lab

AIM: How is hair analyzed in forensics?Do Now: Compare the layers of a pencil to the layers found in hair. What would the paint represent? The wood? The lead?

HW: Textbook Read pages 201-204. Write out and answer each bold faced question on hair identification

What are the parts of a hair strand?

• 1. Root/bulb• Embedded in hair follicle

• 2. Shaft• Composed of 3 layers

–Cuticle–Cortex–Medulla

• 3. Tip• Where the hair strand ends

How can you determine different types of hair by analyzing the

medulla?

Medulla

• 3 types of medulla found in human hairs– I.Continuous - most East Asian scalp hairs + pubic hair– II.Fragmented – – III.Absent-

Most human scalp hairs other than East Asian

Continuous Medulla

Solid canal throughout hair

Fragmented Medulla

Interrupted canals throughout hair

Absent Medulla

No Medulla Found

Root of Hair

• Provide the tools to produce hair and continue its growth

• 3 Stages of Growth (different looking roots)– Anagen -initial phase may last up to 6 years, root is

flame shaped– Catagen –transition phase (2-3 weeks), root is

elongated– Telogen –phase where hair naturally falls out of the

skin, root is club-shaped

How could Fajardo Aceves Jesus Manuel remove his hair

Why is hair analysis so important?• We lose and replace about 100 hairs per

day.• It’s likely that we left a strand of hair in

everyplace we traveled to yesterday

Why are hairs collected for drug tests? • Materials that come into the body can be

delivered by blood to hair follicle

• Material can be deposited in cortex of hair

Why are hair follicle drug tests becoming widely used?• Drugs and their metabolites can be detected over

longer periods of time than blood, urine, or saliva tests• Since hair grows about 1cm (½ inch) a month, we can

get a timeline of when drug use• We can see how often person uses drugs (every week

or once in the last 3 months)

Tuesday

Substance Urine Hair Blood/Saliva

Alcohol 6–24 hours up to 2 days 12–24 hours Methamphetamine 3 to 5 days up to 90 days 1–3 days MDMA (Ecstasy 24 hours up to 90 days 25 hours Cannabis 3 to 7 days, up

to >30 days after heavy use and/or in users with high body fat

up to 90 days 2–3 days in blood, up to 2 weeks in blood of heavy users. Saliva for

2–6 hours

Cocaine 2 to 5 days up to 90 days 2 to 5 days

Cotinine (a break-down product of nicotine)

2 to 4 days up to 90 days 2 to 4 days

Heroin 3 to 4 days up to 90 days 1– 2 days

LSD 24 to 72 hours up to 90 days 0 to 3 hours

What other materials can be traced in hair?• Poisoning by heavy metals (Arsenic, Mercury,

lead)• Dietary deficiencies (low vitamin and mineral

levels)

What is a drawback to hair testing?• Scalp oils coat the cuticle of the hair and sometimes

capture materials from environment Ex: crack smoke in car

• Can cause “false positives”• Scientists must be careful to examine only the cortex

of the hair

http://www.youtube.com/watch?v=GPrYZ9wwCv4

• http://www.cbsnews.com/video/watch/?id=7253008n