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Chapter 8

Hair, Fibers, and Paint
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Hair Follicle
hair is an appendage of the skin, growing out of what organ know as the...?
cortex, medulla, cuticle
The three layers of the hair shaft are the?
True
true of false the scales of most animal hairs can be described as looking like shingles on a roof
Cortex
this contains the pigment granules that impart color to hair
Medulla
The central canal running through many hairs is known as the
medullary index
The diameter of the medulla relative to the diameter of the hair shaft is the
1/3;1/2 or greater
Human hair generally has an index of less than; the hair of most animals has an index of ;
absent?
Human head hairs generally exhibit _______ medullae
Animal
If a medulla exhibits a patterned shape, the hair is ____ origin
Anagen, catagen, telogen
THe three stages of hair growth is
Cannot
A single hair ____ be individualized to one person by microscope examination
Comparison
In making hair comparisons, it is best to view the hairs side by side under a ______ microscope
Pubic
These hairs are short and curly witha a wide variation and a shaft diameter
is
It ____ possible to determine when hair was last bleached or dyed
False
The age and sex of the individual from whom a hair sample has been taken can be determined through an examination of the hairs morphological features
often
Hair forcibly removed from the body ____ has has follicular tissue adhering to its root
DNA
Microscopic hair comparisons must be regarded by police and courts as presumptive in nature, and all positive microscopical hair comparisons must be confirmed by ____ typing
False
Currently DNA typing can individualize a single hair_____
Anagen
A ___ hair root is a likely candidate for DNA typing.
50
A minimum collection of ___ full length hairs normally ensures a representative sampling of head hair.
24
a minimum collection of ___ full length pubic hairs is recommended to cover the range of characteristics present in this region of the body.
natural
__ Fibers are derived totally from animal or plant sources.
Cotton
The most prevalent natural plant fiber is ___
True
T or F: Regenerated fibers, such as rayon and acetate are manufactured by chemically treating cellulose and passing it through a spinneret
Synthetic
Fibers manufactured solely from synthetic chemicals are classified as ____
False
T,F: Polyester was the first synthetic fiber
Polymers
___ are composed of a large number of atoms arranged in repeating units.
molecule
The basic unit of the polymer is called the ___
Proteins
____are polymers composed of thousands of amino acids linked in a highly organized arrangement and sequence
True
T,F: A first step in the forensic examination of fibers is to compare color and diameter.
Visible
The micropspectrophotometer employing ____ light is a convenient way for analysts to compare the colors of fibers through spectral patterns.
Gas
The dye components removed from fibers can be separated and compared by _____ chromatagraphy
Birefringence
Synthetic fibers possess the physical property of ____ because they are crystalline.
infared
The microspectrophotometer emplying _____ light provides rapid and reliable method for identifying the generic class of a single fiber.
class
Normally fibers posess ____ characteristics
individual,vehicle
The two most important components of dried paint from the criminalists point of view are the _____,______
layer structure
The most important physical property of paint in a forensic comparison is _____
Binder
Paints can be individualized to a single source only when they have a sufficiently detailed____
Electrocoat Primer
this layer provides corrosion resistance for the automobile
Clear Coat
Eye Appeal of the automobile comes from the _____ layer
Binder
Pyrolysis gas chromatography is a particularly valuable technique for characterizing paints_____
Inorganic
Emission spectroscopy can be used to identify the ____ components of paints pigments
True
T,F: Paint samples removed for examination must always include all of the paint layers