Transcript Hair
Hair Analysis What is Hair? Hair= • Appendage of skin • Grows out of a hair follicle • Root, Shaft and Tip Layers of Shaft Medulla Cortex Cuticle Cuticle Layer • Tough and Resistant Outer Layer • Overlapping scales made of keratin • Used for species identification Casting to see scale pattern Cortex Region • Beneath Cuticle • Contains pigment granules that give color to hair • Look at color, shape and distribution of granules Medulla Region • Center Region of Hair • Presence and pattern varies from person to person and from hair to hair on an individual Uniserial Multiserial Vacuolated Lattice Fragmented Intermittent Continuous Amorphous Medulla • Human hairs generally have Fragmented or Absent medulla • Exception:Mongoloid/Asian - usually have continuous medulla Roots • Necessary for growth of hair • Can tell the growth stage of hair: – Anagen= Actively growing, root is flame shaped – Catagen= Slowed growth, root elongated and shrunken – Telogen= Hair growth ends, root clubshaped, hair falls out of follicle Roots Follicular Tissue Catagen Anagen Telogen Hair: Comparative Studies • • • • • Need comparative microscope Need multiple hairs for comparison Look at overall color, length and diameter Medulla absent or present? Distribution, shape, color intensity of pigment granules in cortex Hair: Comparative Studies • • • • Dyed Hair (Paint Roller)vs Natural? Bleached Hair (Yellowish tint) Time of Dyeing? (Hair grows 1cm/month) Nits or fungal infections? Hair: Comparative Studies • Types: – Scalp= uniform diameter and pigment distribution – Pubic= short, curly and diameter variations – Facial=Coarse, triangular, blunt tips Hair: Comparative Studies • Race: – Black= Tight curls, dense uneven pigment distribution, flat to oval hair in cross section – Caucasian= Straight or wavy, fine to coarse pigments that are evenly distributed, oval to round hair in cross section Hair: Comparative Studies • Age and Sex: – Age and Sex Determination= Most No, – Baby Hair short, thin and fine pigment Hair: Comparative Studies • Forcibly Pulled Hair – See follicular tissue at root • Isolate Nuclear DNA • Telogen hairs not a good source for DNA • Mitochondrial DNA Hair: Comparative Studies • Drug use/ Poisoning Hair Collection • Need control samples • Need at least 50 scalp hairs from an individual • Need at least 20 pubic hairs from an individual • Need full length hair Cut close to scalp, need minimal amount of head and body hair • http://www.youtube • http://www.youtube .com/watch?v=Z9L .com/watch?v=Bd170NWE i3MC4d-HmY • http://www.youbea uty.com/hair/videothe-science-of-hair