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197 Cards in this Set
- Front
- Back
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What are the three main components of hair?
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Cuticle
Cortex medulla |
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A compound microscope is equipped with two objectives lenses (10x and 45x) and has 10x ocular lens. The highest magnification attainable with this instrument is....
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450x
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Which part of the hair shaft is the most resistant to chemical decomposition?
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cuticle
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Which microscope is best suited to study the birefringent minerals and fibers?
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polarizing microscope
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as magnification of the compound microscope is increased, the field of view....
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decreases
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by far the most prevalent plant fiber is ...
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cotton
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The medullary index of human hair is _____ the medullary index for most other animals.
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less than
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pigment granules that impart hair with color are found in the ....
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cortext
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beard hairs are coarse and normally_____in cross section
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Triangular
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Which microscope has the largest potential working distance (distance between the specimen and the objective lens)?
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Steroscopic
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Nuclear DNA can be most successfully accomplished on hairs that have been removed during which stage of growth?
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Anagenic
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In the design of the polarizing microscope, the polarizer is placed between the....
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light source and the sample stage
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A microscope uses a combination of ____to magnify an image
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lenses
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Which race is most likely to have head hair with continuous medullae?
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Mongoloid (asian)
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What is made of natural polymers?
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Starch
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The follicular tag contains....
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DNA
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What is the earliest microscope?
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magnifying glass
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Magnifies image observed when looking through the lens, cannot be seen directly (without lens)
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Virtual Image
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Can be seen directly without the use of a lens
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Real Image
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What makes an image appear larger thorugh a magnifying glass?
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The light rays bending or refracting
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Lower lens, positioned directly over the object or specimen
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objective lens
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lens which the viewer looks through
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ocular lens (eye piece lens)
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Name 6 microscopes
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compound microscope
comparision microscope steroscopic microscope polarizing microscope microspectophotometer scanning electron microscope |
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The support on which the instrument rests
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base
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hinged to base, supports microscope, acts as a handle for carrying
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Arm
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horizontal plate where specimens or slides are placed. Spring clips help keep the slide in place
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stage
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Hollow tube where objective and eyepiece lenses are mounted (opposite ends)
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Body tube
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knob focuses the microscope lenses on specimen by raising or lowering the body tube
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coarse adjustment
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knob similar to the coarse adjustment but the movements are smaller in magnitude
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fine adjustment
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artificial light provided by a light bulb in order to illuminate the specimen
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illuminator
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collects the light from the illuminator and concentrates it onto the specimen.
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Condenser
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closest to the specimen, can change from one lens to another. Several objectives are on mounted on a revolving nosepiece.
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Objective lens
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lens closest to the eye
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ocular lens
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one eyepiece
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monocular
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two eyepieces
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binocular
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multiply the magnification from the ____and the ____to determine the ____ _____ power.
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eyepiece
objective total magnification |
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Area of the specimen that can be seen after it is magnified
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field of vision
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thickness of specimen that is entirely in focus under a microscope
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depth of focus
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Increasing magnification power in the field of vision and the ____ ____ ____ ____.
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Depth of focus decreases
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Two compound microscopes combined into one
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comparison microscope
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a Steroscopic microscope is good for what types of specimens? Why?
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bulky things like tee shirts guns, tools, etc. It has a large working distance
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A large working distance increases the....
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field of view and the depth of focus
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vibrates in all directions perpendicular to the traveling lights direction.
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UNpolarized light
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polarizes light
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polarizer
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light confined to a single plane of vibration
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polarized light
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if unpolarized light goes through a polarizer and then an analyzer what will happen?
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NO LIGHT "EXTINCTION"
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Light can split rays into 2 different refractive indexes.
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Birefringent
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What is a microspectrophotometer used for?
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identify drugs and substances
Very advanced |
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Illuminates specimens with a beam of electrons.
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Scanning electron microscope
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What is a scanning electron microscope good at detecting?
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individual elements such as gun powder residue
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What are 4 things froensic scientists look for when examining hair?
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1. color
2. structure 3. morphology 4. DNA extraction (If warrented) |
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External outgrowth
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apendage
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what part of the hair do scientists look at for intense examination of three features
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Shaft
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What three features are contained in the shaft of the hair?
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cuticle
cortex medulla |
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Hair extends from the ____ which is embedded in the ____ and continues into the ____ and is terminated at the ____.
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root/bulb
shaft tip end |
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The follicle of the hair is actually an___
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organ
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Waxy and protects the hair
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cuticle
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resistant to chemical decomposition
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cuticle
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Has an ability to retain structual features
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cuticle
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What do make a cast of hair out of and why do you do that?
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Rubber cement or clear nail polish
You do this to study the outer layer of the hair. |
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Is human hair or animal hair more distinguishable?
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Animal hair - shingle like cuticles
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embedded with pigment granules that gives hair color
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cortex
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what part of the hair is very individualized with identifying har
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cortex
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What are three important parts of the cortex?
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color
shape distribution |
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A collection of cells that look like canal running through hair
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medulla
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The medulla CAN or CANNOT be bigger than the hair itself?
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CANNOT
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Humans medulla index is usually....
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less than 1/3 (SMALL)
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Animals medulla index is usually....
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greater than 1/2 (BIG)
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Medullary index =
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diameter of medulla/diameter of hair shaft
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peresence of a medulla ____varies between person to person. EVEN within one individual
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Varies
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medulla patterns can be
1 2 3 |
continuous
interrupted fragmented |
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deer have ____ medullas
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giant
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cats have____ medullas
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fragmented
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What three phases does hair grow in?
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Agagen
Catagen Telogen |
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The growth of hair depends on....
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what stage its in
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The longest stage of hair. continiously growing
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Anagen phase
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How long does the anagen phase last?
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up to 6 years
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What is ususually contained in the anagen phase?
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follicle tag
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The shortest phase of hair
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catagen phase
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How long does the catagen phase last?
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2-3 weeks
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hair is growing at a decreasing rate and sometimes shirking
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catagen
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Roots of the hair have an elongated appearance in this phase
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catagen
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Hair is growing very slowing during this phase
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catagen
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root bulb shrinks and starts to get pushed out of the hair follicle during this stage
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catagen
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What is the naturally shedding phase of hair?
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Telogen phase
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How long does the telogen phase last?
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2-6 months
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Hair growth ends during this phase
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telogen
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roots have cubed shaped appearances during this phase
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telogen
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There is most likely NO follicle tissue or DNA in this phase of hair
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telogen
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Can the body area from which a hair originated be determined?
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Yes, to a certain extent.
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Uniform diameter and pigment color
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scalp hair
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wide variations of shaft diameter with continuous medullae.
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pubic hair
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coarse, triangular cross section with blunt tips
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beard hair
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Can the racial origin of the hair be determined?
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Yes, but there are exceptions!
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(race) wide diameter with continuous medullea.
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Mongoloid (asian)
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(race) straight or wavy with fine to coarse evenly distributed pigments
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Caucasian
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(race) normally kinky with dense, unevenly distributed pigments
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African
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Can the age and sex of an individual be determined from a hair sample?
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NO.
Except for an infant. |
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Is it possible to determine whether hair was forcibly removed from the body?
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Yes with small exceptions.
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Adhering to the root is follicular tissue
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Pulled hair
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Root is bulbous shaped free of any adhering tissue
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Natural shed hair
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Received from both parents and found in hair root or in follicular tissue adhering to the root.
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Nuclear DNA
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Received only from the mother.
Found outside the nucleus of a cell. |
Mitochondrial DNA
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YOu can link human hair to certian persons by...
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nuclear DNA
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Can mitochondrial DNA individualize a person?
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NO, but it can exclude a significant amount of a population.
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Can you compare head hair to pubic hair?
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NO
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How many hairs does a comparison require from one person?
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50 hairs
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How many pubic hairs are required for a comparison?
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24 full length pubic hairs.
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Natural fibers are derived from
1 2 |
animal sources
plant sources |
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What animal sources are fibers derived from?
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sheep
goat furs |
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what plant sources are fibers derived from?
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cotton
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What are two types of manufactured fibers?
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Regenerated fibers
Synthetic Fibers |
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What is extracted and chemically treated from machine made(regenerated) fibers?
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Cellulose
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What are three synthetic fibers?
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Nylon
Polyester acrylic |
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A naturally occuring polymer is____
What is an example |
Cellulose
Starch |
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what is a simple molecule?
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water
H2O |
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What is a complex molecule?
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heroin
C21H23O5N |
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Responsible for glue plastic and cellulose
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polymer
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a polymer starts as a ____ substance and then is ____ and ___ and be ____ ____
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Simple
repeated linked infinity long |
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What are three ways to identify and compare fibers?
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microscopic examination
dye comparison chemical composition |
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What five shapes can fibers be?
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flat
round dumbell multi-lobed trilobal |
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What does TLC stand for
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thin layer chromotography
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What type of microscope is best used when examining fibers?
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Microspectrophotometer
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What are two phases dye composition? (TLC PLATE)
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Stationary
mobile |
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Paint as a physical evidence is most frequently encounter in ____ and ____ cases.
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Hit and run
Burglary |
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Paint is spread onto a surface and dries into a hard film consisting of ____ and ____ suspened in a ____.
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pigments
additive binder |
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support medium fir the pigments and additives, polymetric substance
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Binder
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The automotive finishing system for steel ususally consists of at least FOUR organic coatings:
1 2 3 4 |
Electrocoat primer
primer surface basecoat clear coat |
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Applied directly to steel body of the car
Why? |
electrocoat primer
corrosion resistance |
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consists of epoxy based resins, uniform appearence and thickness. Color ranges from black to gray
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electrocoat primer
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Applied before base/color coat. is a polymer.
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Primer surface
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Smooths out and hides any imperfections. Is highly pigmented. Epoxy modified polyesters or urethanes
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primer surface
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color pigments are used to minimize color contrast between primer and top coats
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primer surface
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integrity depends on ability to resist weather, UV radiation, and acid rain.
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Basecoat/colorcoat
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acrylic based polymer.
Organic based pigments vs. heavy metal pigments |
basecoat/colorcoat
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improve gloss, durability, and appearance
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clear coat
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acrylic based, polyurethane is increasing in popularity.
provides etch resistance and appearance |
clear coat
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What does PDQ stand for?
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Paint data query
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The Bertillion System is devised of what three things?
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Portrait Parle
Full length and profile photographs anthropometry |
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Description of physical characteristics and dress
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Portrait parle
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System of identification using measurements of body parts
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Antropometry
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How did Chinese people use fingerprints 3000 years ago?
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used fingerprints to sign legal documents
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What Did William Herschel do with fingerprints?
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required Indian citizens to sign contracts with the imprint of thier right hand
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He was a scotting physican in Japan hospital and published his views on using fingerprints as personal identification in 1880
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Henry Falud
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Who proposed the three patterns of fingerprints?
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Galton
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What are the three patterns of finger prints?
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whrol
loop arch |
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who found out that no two finger prints are alike and that they do NOT change over the lifetime.
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Galton
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A finger print is an _____ ____
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Individual characteristic
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outer portion of the skin
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epidermis
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boundary between epidermis and dermis
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dermal papillae
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inner skin
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dermis
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What did John Dillenger try to do?
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Alter his finger prints by burning them off
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What is the least common fingerprint pattern?
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Arch 5%
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what is the most common fingerprint pattern?
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loops 60-65%
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loop opens to thumb
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radial loop
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loop opens to little finger
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ulnar loop
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How many prints are in the FBI data system?
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50 million
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first print
value |
R.Index/R.Thumb
16 |
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second print
value |
R.Ring/R.Middle
8 |
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third print
value |
L. Thumb/ R. Little
4 |
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fourth print
value |
L. middle/ L. index
2 |
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5th print
value |
L. little/ L. ring
1 |
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What is the FBI's primary classification system based off of?
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the presence or absence of a whrol pattern
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What does IAFIS stand for?
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Intergrated automated fingerprint identification system
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The ability of a computer to scan and digitally encode fingerprints so that they con be subjected to high speed computer processing.
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IAFIS
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How long would it take to go through each fingerprint by hand?
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67 years
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When you are doing a fingerprint search and comaprision you want to firs start with ____ and then if you do not come up with any possible matches then do the ____
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local AFIS
IAFIS |
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Invisible fingerprint
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Latent fingerprint
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made by fingers toughing a surface after the ridges have been in contact with a colored material such as blood paint grease or ink.
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Visible prints
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ridge impressions left on a soft material such as putty, wax, soap, or dust
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plastic prints
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Impressions caused by transfer of body perspiration or oils on finger ridges to the surface of an object
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latent prints
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What does RUVIS stand for?
What is it? |
reflected ultraviolet imaging system
a LIGHT GUN you shine at finger print to make it visible (no need for powder) |
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Five ways to develop latent prints
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Ninhydrin
powders superglue fuming physical developer iodine fuming |
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What happens when you place an object in for iodine fuming to find finger prints?
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Put object in chamber with iodine crystal.
Heat Iodine crystals melt from solid to vapor vapor adheres to the fingerprints making them visible |
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Solid to a vapor
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sublimination
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What happens when you turn off the iodine fuiming machine?
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The prints disappear. You have to take a photo of the print or spray it with starch.
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How do you use Ninhydrin to devlope prints?
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You spray it with an aresol can.
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effective for developing latent prints on porous articles that may have been wet at one time
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physical developer silver nitrate liquid reagent
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You have to do chemical methods of fingerprint developing in very particular order
1 2 3 |
Iodine fuming
ninhydrine physical developer _washes away protiens that are needed for ninhydrine |
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How does superglue fuming work?
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PLace object in chamber
place a small amount of super glue in chamber heat glue adheres to the prints making the visible with a crusty white substance |
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How do you preserve finger prints?
1 2 3 |
Visualize
close up photo over all photo |
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print should be visualized using the appropriate technique
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visulized
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In order to be permanently preserved for future comparisons, a photograph must be taken of the print
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Close up photograph
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Photographs must be taken to provide an overall view of the print's location in relation to other evidental items at the crime scene.
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Overall photograph
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What are three substanced that are found along friction ridges of fingers?
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salt
water proteins |
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space between the specimen and the objective lens
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working distance
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presents a distinctive three dimensional image
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stereoscopic microscope
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illumination required to view a transparent object
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transmitted illumination
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eyepiece multiplied by objective lens
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magnification
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the thickness of a spcimen in focus
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depth of focus
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size of specimen area being observed
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field of view
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provides a simultaneous view of two specimens
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comparison microscope
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used to examine birefringent materials
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polarizing materials
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the image seen through a compund microscope
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virtual image
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image formed by the actual convergence of light rays on a screen
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real image
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illumination of specimen from above
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vertical illumination
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the lower lens of a microscope positioned directly over the specimen
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objective lens
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