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Hair Analysis Research

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Hallie Gentry

on 21 February 2013

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Transcript of Hair Analysis Research

By: Hallie Gentry Hair Analysis Research The Medulla Hair Morphology The innermost layer of the hair
It is made of cells that form a shaft through the middle of the hair
The medulla can be absent, fragmented, interrupted, or continuous in the shaft of the hair Hair Follicle Shaft of Hair The shaft of the hair is the part seen above the skin
It is made up of dead cells that have turned into keratin and binding materials
The hair shaft if made up of three layers: the cuticle, the cortex, and the medulla The Cuticle The cuticle is the first layer of the shaft
It is a hard, scaly, protective structure that shields the inner layers of the shaft from damage
The structure of the cells that make up the cuticle can vary and this can determine the species that the hair came from
There are three basic patterns of cells that make up hair: coronal, spinous, and umbricate The Cortex The cortex is the middle layer of the hair shaft
It contains pigment granules which determine the color of the hair
The cortex can help scientists determine what species the hair belongs to Bibliography Each individual hair on the body is made up of many parts

http://1.bp.blogspot.com/_xCfdo_360cw/TS82_bLt6nI/AAAAAAAAApQ/Yf-3PmN-fPo/s400/allabouthair_img_structure.jpg Continuous--no breaks in the medulla
from http://www.fbi.gov/hq/lab/fsc/backissu/jan2004/research/2004_01_research01b.htm Interrupted--few short breaks
from http://www.fbi.gov/hq/lab/fsc/backissu/jan2004/research/2004_01_research01b.htm http://shs.westport.k12.ct.us/forensics/09-trace_evidence/splitting_hairs.htm
http://www.exploreforensics.co.uk/hair-and-fibres.html Fragmented--few parts of medulla visible http://www.fbi.gov/hq/lab/fsc/backissu/jan2004/research/2004_01_research01b.htm Absent--no medulla visible
http://www.fbi.gov/hq/lab/fsc/backissu/jan2004/research/2004_01_research01b.htm The Medulla continued The medulla in a human is less than 1/3 of an inch across
Other species have a larger medullary index
Scientists can use the medullary index to determine the species that the hair belongs to Hairs grow out of deep tubes called follicles
Each hair is made up of many parts
Hair follicles are found on almost all parts of the body
The follicle contains the shaft of the hair
If there is blood or skin left on the follicle, it can be tested for DNA evidence http://upload.wikimedia.org/wikipedia/commons/thumb/4/4d/Hair_follicle-en.svg/250px-Hair_follicle-en.svg.png Root of Hair The root of a hair is embedded in the follicle
It ends in an a structure called the hair bulb http://www.healthytextures.com/custom/hair%20root.jpg Root http://trialx.com/curetalk/wp-content/blogs.dir/7/files/2013/01/hair_shaft_cross_section.jpg http://www.trimble.k12.ky.us/tchsweb/teachers/njones/2009-10%20School%20Year%20Stuff/ForensicsPowerPoints/Chapters%208%20-%20%20Analysis%20Hair,%20Fiber,%20Paint/Cuticle%20types.jpg http://2.bp.blogspot.com/_xCfdo_360cw/TS837BuqlbI/AAAAAAAAApY/x4RFyfleizY/s400/hair_detail2_tags.jpg http://www.personal.psu.edu/users/c/l/clv14/sci101/images/standardhair%20copy.jpg The Difference
Human and Animal Hair In most humans, the color of the hairs is consistent throughout the entire shaft of the hair but with animals the shaft could be made up of a multitude of colors
The pigment granules found in the cortex of human hairs are spread out evenly around the space, but in animals the pigment granules are packed densely around the medulla
The medulla in human hair doesn't have an exact shape and it is usually broken or fragmented, whereas the medulla in an animal's hair is usually continuous with an exact shape
In human hair the cuticle has a scaly coating that is usually the umbricate pattern or sometimes the coronal pattern, but in animals the pattern can vary between umbricate, coronal, or spinous http://intro.chem.okstate.edu/chemsource/Forensic/forechem12.gif http://resource.rockyview.ab.ca/t4t/forensicscience25/Module2/Images/medulla_variations.jpg Can scientists determine what area of the body that a hair came from? Scientists can determine which hairs came from which area of the body
They do this by examining each hair and comparing/contrasting the properties of the hairs
Head hair has a smaller diameter than other body hairs and it is evenly colored
Hair from the legs and trunk area have more medulla than hair from the head and the color varies
Pubic hair is short and curly and it has a more pronounced medulla
Facial hair is very coarse and the shape may vary http://4.bp.blogspot.com/-r26r4GnBUTY/UA3OwKmBqrI/AAAAAAAAAtM/7ozPeqrTM9Y/s1600/Fig.+3+with+caption.jpg Can racial origin, age and gender be determined from hair? In some cases racial origin can be determined using hair by analyzing the different properties of it
African American hairs are usually kinky and contain dense, unevenly distributed pigments, whereas Caucasian hairs are usually straight or wavy with evenly distributed pigments
A cross-sectional view of the hair can also be used to determine the race because African American hairs have a flat or oval shape whereas Caucasian hairs have a a round or oval shape
Age cannot be determined using hairs unless the hair belongs to an infant or baby, because their hairs are fine and short. Gender can be determined if the hair has DNA in it. http://3.bp.blogspot.com/-nNmhhmYhWUg/TsPnho85HcI/AAAAAAAAAFk/uHeJ4o963wg/s1600/Differnt+races+hair.jpg Can Scientists determine whether or not hair has been forcibly removed? Scientists can determine whether or not the hair has been forcibly removed, fallen out, or cut
If the root of the hair has follicular tissue then it has been forcibly removed
Hair that has fallen out will not have any follicular tissue left on the root
It is sometimes hard to determine if a hair was pulled out or if it fell out because the amount of left over tissue could vary depending on how quickly or slowly the hair was removed http://www.hairfactz.com/images/pulled2.jpg http://www.fbi.gov/about-us/lab/forensic-science-communications/fsc/jan2004/research/images/fig22.jpg Fallen Out Forcibly Removed Can hairs be individualized to one person? Hairs can be individualized to one person by using DNA evidence
If a hair does not have DNA or traces left of skin or blood it becomes very difficult to determine the owner of the hair
If hairs lack DNA one can still determine the color, gender, and possibly the race of a suspect, but without DNA it is very difficult to get an exact match http://blogs-images.forbes.com/daviddisalvo/files/2011/11/DNA.jpg How are hair samples collected and preserved? At crime scenes if hairs are found they are picked up with either tweezers or gloved hands and placed into a sealed envelope, tubes, or vials and then labeled
If hair is attached to objects or stains the it should be left intact and the entire area/object involved should be wrapped up or sealed depending on the size of the area/object involved
When taking hair samples from a suspect tweezers should be used to obtain about 50 full-length hairs from the head and about two dozen full length pubic hairs
Hair should be taken from all areas of the body and the hair should never be cut
Hairs are best preserved in dry, sealed unwaxed envelopes, but they can also be preserved on glass microscope slides http://upload.wikimedia.org/wikipedia/commons/9/92/US_Army_CID_crime_scene_investigator.jpg http://www.evidentcrimescene.com/cata/evid2/envelopeGlassine.jpg
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