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 – Most human scalp hairs other than – III.AbsentEast Asian Continuous Medulla Fragmented Medulla Absent Medulla Solid canal throughout hair No Medulla Found Interrupted canals throughout hair 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 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 2–6 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