FRSC 2600 EXAM 3 QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTIONS VERIFIED LATEST UPDATE
trace evidence
any small pieces of material, man-made or naturally occurring (animal, plant, or mineral)
examples of physical or trace evidence
hair, fibers, glass, soil, sand, etc.
test questions for trace evidence
-what is it?
-is it man-made or natural?
-what is its source?
-how common is it?
-can it be identified to a single source?
human hair
one of the most frequently found pieces of evidence at the scene of a violent crime, can
provide a link between the criminal and the act
hair morphology
the study of structure and form of hair
hair shaft
part of the hair that sticks out of the skin
hair root
lies below the epidermis
,hair follicle
structure from which the hair grows
hair shaft composition
cuticle, cortex, medulla
shaft cuticle
outside covering, made of overlapping scales
shaft cortex
outer layer made of keratin and imbedded with pigment, also contains air sacs called
cortical fusi
shaft medulla
inside layer running down the center of the cortex
hair cuticle
outermost layer of hair which is covered with scales, scales also always point toward
the tip of the hair, scales differ between species of animals and are named based on
their appearance
scale types
mosaic, pectinate, imbricate, petal, diamond petal, chevron
human scales
in order to visualize scales: paint fingernail polish on a slide, place a hair on the polish,
lift off the hair and observe the scale imprints
cortex
gives the hair its shape
melanin
,pigment granules that give hair its color
cortical fusi
air spaces, usually found near the root but may be found throughout the hair shaft
medulla
hair core that is not always present
medulla types
continuous, interrupted, fragmented, absent
medullary index
determined by measuring the diameter of the medulla and dividing it by the diameter of
the hair
medullary index for human hair
generally less than 1/3
medullary index for animal hair
generally greater than 1/2
hair shape
can be straight, curly or kinky depending on the cross-section, which may be round,
oval or crescent-shaped
round hair shape (cross-section)
straight
oval hair shape (cross-section)
curly
crescent hair shape (cross-section)
kinky
, anagen (hair phase)
hair that is growing, lasts up to five years
catagen (hair phase)
hair at rest
telogen (hair phase)
hair that is dying, lasting two to six months
hair growth rate
0.05 mm per day or 1 cm per month, approximately one half inch per month
hair comparison
color, length, diameter, distribution, shape and color intensity of pigments granules
(dyed hair has color in cuticle and cortex, bleaching removes pigment and gives yellow
tint), scale types, presence of absence of medulla, medullary type, medullary pattern,
medullary index
collection of hair
questioned hairs must be accompanied by an adequate number of control samples
(from victim, possible suspects, others who may have deposited hair at the scene),
control sample (50 full-length hairs from all areas of scalp, 24 full-length pubic hairs)
Caucasoid (European) hair
-fine to medium coarseness
-generally straight or wavy
-colors ranging from blonde to brown to black
-hair shafts vary from round to oval in cross section
-fine to medium sized, evenly distributed pigment granules
COMPLETE SOLUTIONS VERIFIED LATEST UPDATE
trace evidence
any small pieces of material, man-made or naturally occurring (animal, plant, or mineral)
examples of physical or trace evidence
hair, fibers, glass, soil, sand, etc.
test questions for trace evidence
-what is it?
-is it man-made or natural?
-what is its source?
-how common is it?
-can it be identified to a single source?
human hair
one of the most frequently found pieces of evidence at the scene of a violent crime, can
provide a link between the criminal and the act
hair morphology
the study of structure and form of hair
hair shaft
part of the hair that sticks out of the skin
hair root
lies below the epidermis
,hair follicle
structure from which the hair grows
hair shaft composition
cuticle, cortex, medulla
shaft cuticle
outside covering, made of overlapping scales
shaft cortex
outer layer made of keratin and imbedded with pigment, also contains air sacs called
cortical fusi
shaft medulla
inside layer running down the center of the cortex
hair cuticle
outermost layer of hair which is covered with scales, scales also always point toward
the tip of the hair, scales differ between species of animals and are named based on
their appearance
scale types
mosaic, pectinate, imbricate, petal, diamond petal, chevron
human scales
in order to visualize scales: paint fingernail polish on a slide, place a hair on the polish,
lift off the hair and observe the scale imprints
cortex
gives the hair its shape
melanin
,pigment granules that give hair its color
cortical fusi
air spaces, usually found near the root but may be found throughout the hair shaft
medulla
hair core that is not always present
medulla types
continuous, interrupted, fragmented, absent
medullary index
determined by measuring the diameter of the medulla and dividing it by the diameter of
the hair
medullary index for human hair
generally less than 1/3
medullary index for animal hair
generally greater than 1/2
hair shape
can be straight, curly or kinky depending on the cross-section, which may be round,
oval or crescent-shaped
round hair shape (cross-section)
straight
oval hair shape (cross-section)
curly
crescent hair shape (cross-section)
kinky
, anagen (hair phase)
hair that is growing, lasts up to five years
catagen (hair phase)
hair at rest
telogen (hair phase)
hair that is dying, lasting two to six months
hair growth rate
0.05 mm per day or 1 cm per month, approximately one half inch per month
hair comparison
color, length, diameter, distribution, shape and color intensity of pigments granules
(dyed hair has color in cuticle and cortex, bleaching removes pigment and gives yellow
tint), scale types, presence of absence of medulla, medullary type, medullary pattern,
medullary index
collection of hair
questioned hairs must be accompanied by an adequate number of control samples
(from victim, possible suspects, others who may have deposited hair at the scene),
control sample (50 full-length hairs from all areas of scalp, 24 full-length pubic hairs)
Caucasoid (European) hair
-fine to medium coarseness
-generally straight or wavy
-colors ranging from blonde to brown to black
-hair shafts vary from round to oval in cross section
-fine to medium sized, evenly distributed pigment granules
