hair and fiber ppt

Chapter 5 & 6:Hair and FiberFor three days after death, hair and fingernails continue to grow butphone calls taper off.

Johnny CarsonComedian and television host

Kendall/Hunt Publishing Company

Kendall/Hunt Publishing Company*


Hair - a thin filament produced by mammals from a hair follicle

Made of protein called keratin (makes fingernails too)



Hair is class biological - circumstantial evidenceunlessDNA is recovered making it _________________________ evidenceIndividual biological - circumstantial


HAIR IS MORPHOLOGICALLY LIKE A PENCILMedulla

Cortex

Cuticle



The Medullamedulla = hair core (not always visible)

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The Medullamedulla = hair core (not always visible)

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The Medulla

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Same hair under microscopeKendall/Hunt Publishing Company*


Every hair (animal/human) has a cuticle and cortex.The medulla is the WILD CARD. It can be:absent / presentcontinuous / fragmentedthick / thinsquare / circles


Human medulla identifiedKendall/Hunt Publishing Company*


*Medullary Index

human hair width has generally less than 1/3 medulla.

animal hair width is generally greater than 1/3 medulla.

mouse


*Hair ShaftCuticleoutside scales

cOrtexpigment (a color speck) ovoid body (big color speck)contains air pockets (why hair floats)

Medullaalthough its black, it doesnt contribute to hair colorNO PIGMENT


Kendall/Hunt Publishing Company*The CuticleThe cuticle (scales) differ between species of animals and are named based on their appearance. The three basic patterns are:

CoronalSpinousImbricate


cuticlehealthy*


Kendall/Hunt Publishing Company*Scale cast of Human Hair


Kendall/Hunt Publishing Company*Hair Growth (3 parts)Anagenhair that is actively growingCatagenhair is restingTelogenhair that is dying and ready to fall out


Anagen catagen telegenKendall/Hunt Publishing Company*CLEAR CELLS ATTATCHED TO ROOT INDICATE THE HAIR WAS FORCIBLY REMOVED


CROSS SECTION OF HAIRKendall/Hunt Publishing Company*


Kendall/Hunt Publishing Company*Hair as class evidenceColorLengthDistribution, shape and color intensity of pigment granulesDyed hair has color in cuticle and cortexBleaching removes pigment and gives a yellow tint

Scale types Presence or absence of medulla Medullary typeMedullary patternMedullary index


Kendall/Hunt Publishing Company*DNA from HairOnly the root contains DNA.

hair ripped out has more root attached

The hair shaft contains abundant mitochondrial DNA (inherited ONLY from mom).


*Collection of HairHair is best retrieved at crime scene by gloved hand (not tweezers)Questioned hairs must be accompanied by an adequate number of control samples.from victimfrom possible suspectsfrom others who may have deposited hair at the sceneControl Sample50 full-length hairs from all areas of scalp24 full-length pubic hairs


Kendall/Hunt Publishing Company*Hair ToxicologyAdvantages:Easy to collect and storeIs externally availableCan provide information on the individuals history of drug use or of poisoning.Collections must be taken from different locations on the body to get an accurate timeline.


Kendall/Hunt Publishing Company*Hair ToxicologyNapoleon died in exile in 1821. By analyzing his hair, some investigators suggest he was poisoned by the deliberate administration of arsenic; others suggest that it was vapors from the dyes in the wallpaper that did him in.


Kendall/Hunt Publishing Company*More about HairFor additional information about hair and other trace evidence, check out Court TVs Crime Library at:

www.crimelibrary.com/criminal_mind/forensics/trace/1.html


A lab on hair analysisKendall/Hunt Publishing Company*In order to visualize thescales:paint clear fingernail polish on a glass slidewhen the polish begins to dry, place a hair on the polishwhen almost dry, lift off the hair and observe the scale imprintsWhat pattern is seen inthis slide?


Demodicidae Kendall/Hunt Publishing Company*


Kendall/Hunt Publishing Company*The CortexThe cortex gives the hair its shape.It has two major characteristics:Melaninpigment granules that give hair its colorCortical fusiair spaces, usually found near the root but may be found throughout the hair shaft


Different hair Kendall/Hunt Publishing Company*


Kendall/Hunt Publishing Company*SplitEnd of Human Hair


Kendall/Hunt Publishing Company*Students will be able to:Describe the structure of a hair Explain the difference between human and animal hair Explain which characteristics of hair are important for forensic analysis Assess the probative value of hair samples

Hair Analysis


Hair Analysishair is biological class evidence hair can be used to back up circumstantial evidence hair easily holds substancesabsorbs (from within body) adsorbs (rests on outside) substances


Kendall/Hunt Publishing Company*Introductionhair most frequently found pieces of evidence at the scene of a violent crime. can provide a link between the criminal and the crime.From hair one can determine:If the source is human or animalRace (sometimes)Origin of the location on the sources bodyWhether the hair was forcibly removedIf the hair has been treated with chemicalsIf drugs have been ingested


Kendall/Hunt Publishing Company*Hair from skin


Kendall/Hunt Publishing Company*Hair ShapeCan be straight, curly or kinky depending on the cross-section, which may be round, oval or crescent-shaped

Round(Straight) Oval(Curly)Crescent moon (Kinky)


Kendall/Hunt Publishing Company*The RootHuman roots look different based on whether they have been forcibly removed or if they are telogen hairs and have fallen out. Animal roots will vary, but in general have a spear shape.Fallen outForcibly removed


hair and fiber ppt

Documents

hair core

hair growth

hair floatsmedullaalthough

animal hair width

hair folliclemade of

root attachedthe hair

cuticlethe cuticle scales

abundant mitochondrial