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Microscopic Hair Analysis

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chichi's version from 2016-10-25 17:30

Section

Question Answer
Information one can get from hairspecies; race; area of body; treatments
microscopes that are usedstereomicroscopes and compound microscopes are used
macroscopic analysiscolor; diameter; length; shaft form
microscopicpigmentation; shaft form; cross-section appearance; root shape; cuticle pattern; medullary pattern
composed mainly of keratin; also composed of melanin and metallic elementshair
guard hairsouter, protective coat
fur or wool hairsinner coat
tactile hairssensory hairs (whiskers)
Three phases hair grows inanagen, catagen, telogen
Anagengrowth stage (determines length of hair; stage can last between 2 and 6 yrs)
Catagentransitional stage (follicle changes to end growth-club hair; lasts 2-3 weeks)
Telogenresting stage (can last-3 months; shedding occurs and then a transition to anagen phase)
cuticletranslucent outer layer (scales)
scalespoint from proximal (root) end to distal end (tip)
Three patternscoronal; spinous; imbricate
memorize

Section 2

Question Answer
coronalresembles stacks of cups; found on hair of very fine diameter; rodents and bats
spinouspetal-like; triangular shapes that protrude from shaft; hair of seals, cats, and other animals; proximal area of mink hairs
imbricateflattened, overlapping scales; irregular borders and margins; found on humans and many animals
medullacentral core of cells; part of excretory system; maybe present or absent;
black under transmittedmedulla
white under reflectedmedulla
In order to visualize, you must use medium with RI close to hair(1.5-1.6)
Human medullasamorphous
Animal medullasuniserial; multi-serial; lattice; vacuolated; amorphous
Human MI<0.3
Animal MI0.5-0.9
Medullary Indexdiameter of medulla/diameter of hair
memorize

Section 3

Question Answer
cortexcontains pigments; cortical fusi; ovoid bodies; distribution, density, size
eumelaninblack and brown
phaeomelaninred and yellow
cortical fusiair pockets; more prevalent near root and end
ovoid bodiesoval-shaped clumps of undispersed pigments
dyed hairmore even distribution of color; bleaching removes pigment; line of demarcation
animal hair color changes along _______shaft
root shape can be used to differentiate betweenanimal vs human
humans have _____ shaped rootclub
animal root shape is ____________variable
Asian hair tends to have _________ presentmedulla
Asian hairround shape
Caucasian hairslightly less round than Asian hair
African hairoval or elliptical shape
memorize

Section 4

Question Answer
negroid60-90 um diameter
cross sectional shape is flattenednegroid
pigment is dense and clumpednegroid
cuticle variesnegroid and Caucasian
undulation is prevalentnegroid
Caucasian70-100 um diameter
cross sectional shape is ovalCaucasian
pigment is evenCaucasian
undulation variesCaucasian
mongoloid90-120 um diameter
cross sectional shape is roundmongoloid
pigment is dense and streakymongoloid
mongoloidcuticle is thick
undulation is nonemongoloid
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Section 5

Question Answer
forceful hair removalwill contain sheath/follicular tissue
naturally shed air DOES NOT contain sheath materialonly mtDNA available for the most part
Post mortem root bandingeventually hair breaks at this location
human hairfine and thin
animal haircoarse and thick
human cuticlecuticular scales are short board, thin and irregularly annular
animal cuticlecuticular scales are very large and have step-like or wavy projections
human cortexthick, well-striated, and 4-10 time as broad as medulla
animal cortexthin, rarely more than twice as broad as medulla
human medullavaries considerably. usually narrow, continuous, fragmented, or entirely absent
animal medullacontinuous and wider
human pigmentevenly distributed
animal pigmentmostly present near medulla
memorize