Forensic Test 1 Q2

balls

Metabolite

A chemical form of a drug that is the product of one or more biochemical reactions involving the parent drug.

hair follicle

follicles are produced after birth

class evidence

(without follicle cells attached) it cannot be used to identify a specific individual

micrometer

millionth of a meter

cortex

middle layer; largest part of the hair shaft, contains pigment granules

Cortical fusi

small sacs of air within the hair shaft

neutron activation analysis

a useful technique that can identify up to 14 different elements in a single two centimeter long strand of human hair

individual evidence

material that can be related to a single source

melanin granules

bits of pigment in the cortex of a hair

medulla

the central core of the hair. it can be a hollow tube, or filled with cells

morphology

study of form

cuticle

transparent outer layer of the hair; protects the hair

trace evidence

small but measurable amounts of physical or biological material found at a crime scene

keratin

a fibrous protein forming the main structural constituent of hair, feathers, hoofs, claws, horns, etc; produced in the skin makes hair strong and flexible

comparison microscope

a compound microscope that allows the side by side comparison of samples, such as hair of fibers

How often does a full head of hair get replaced?

every third year

People with different colors of hair tend to have different amounts of hair. Which shows the correct order from most to least

Blonde-brunette-red

While getting dressed, you dropped your shirt on the floor and picked up dog hair. When you arrived at school and sat in your desk chair, you transferred some of that dog hair to your chair. This is an example of what

Secondary transfer

Hair analysis may be used to determine all of the following except

Identify of the individual from which the hair came from

The main purpose of hair is to

regulate body temperature

Humans have the most hair on their body

when they are born

The hair shaft is composed of what important protein

Keratin

This layer of hair is made of scales that overlap and point to the distal tip

Cuticle

Human hair generally have what two types of Medulla

Fragmented or solid

On average, how often is hair replaced

every 3 years

Hair is considered what type of evidence? What is the exception to this

It is considered class evidence, an exception would be if the follicle is still attached

If a strand of hair from your dog sticks to your pants when you leave home, then sticks to the seat on the bus, it is what kind of transfer

Secondary transfer

What are two ways to pick up individual strands of hair evidence

Fingers, tweezers, or tape lift

What are two quick and easy ways to store hair evidence

In bindles or coin envelopes

What is the main function of hair

regulate body temperature

What are some additional functions of hair

-Decrease friction -Protect against sunlight -Sensory

What happens to hair density and numbers of hair follicles as a person ages

It decreases

What are the two main parts of hair

Follicle and shaft

What is the name of network of blood vessels that supply nutrients to feed the hair and help it grow

Papilla

What is the function of the sebaceous gland

Secrete oil

The hair shaft is composed of what protein

keratin

The hair shaft is composed of what three layers

cuticle, cortex, medulla

Describe the cuticle

Transparent, protects hair, overlapping scales

Describe the cortex

Middle layer, largest part of the hair shaft, contains pigments

Describe the medulla

Central core of the hair. It can be a hollow tube, or filled with cells.

What are the two main pigments of human hair What colors of hair does each produce

Eumelanin, brown and black. Phemelanin, blonde anad red.

Which layer of the hair shaft provides hair with strength and elasticity and determines the texture and quality of hair

Cortex

Humans typically have what type of medulla pattern

None or fragmented

What are the five types of medulla patterns

Continuous, Interrupted, Fragmented or Segmented, Solid, None

What determines whether hair is curly, straight, or in between

The cross section

Why is it not okay to say two hairs match? What term or phrase should we use instead?

Association/ common origin

What term do we use when hairs do not have a common origin

Exclusion

When collecting hairs from a suspect, how many need to be collected and why

50-100; 50 from the head, typically 25 from pubic region, because inconsistencies occur in each body region

How should you collect hairs from a suspect

By plucking or having the person bend over a large sheet of paper, and rubbing hair so loose hairs fall out

List the six types of hair on the human body

head, eyebrows, eyelashes, beard, mustache, underarm, body, pubic

What are the two most common hairs found at crime scenes

head and pubic

What are the three stages of the hair cycle

anagen, catagen, telogen

Describe the anagen stage

Period of active grow when the cells around the follicle are rapidly dividing and depositing materials

Describe the catagen stage

Transitional or regressive stage that lasts a few weeks; hair growth slows.

Describe the telogen stage

During this final resting stage, the hair follicle is dormant and hairs are easily lost.

The end of the hair that can be used to identify the type of treatment and estimate the length of time since the last cutting is called?

Distal tip

How long does it take for a hair tip to become rounded and lose its unique features

2-3 weeks

How does bleaching change the appearance of hair?

Removes pigment granules - gives hair a yellowish tent, makes hair brittle and disturbs scales of cuticle

On average, how quickly does human hair grow

1.3 cm per month

How are the pigment granules different for the three main racial groups

-European has small, evenly distributed granules -mongoloid/Asian has densely distributed granules -negroid/African has densely distributed granules that may be clumped or varying in size and shape

How do you calculate the medullary index of the hair

Diameter of medulla divided by diameter of entire hair

What does the medullary index tell you about the hair

If is is .5 or more it came from an animal If .33 or less its from a human

Calculate the medullary index of a hair whose diameter is 170 microns wide and whose medulla measures 48 microns. Is this a human or animal hair?

48 divided by 170 = .28 human hair

Describe the three types of cuticle pattern

1. Coronal- resembles a stack of paper cups

2. Imbricate- overlapping scales with narrow margins

3. Spinous- triangular in shape and protrude from hair shaft

Name three macroscopic characteristics of hair

1. Length pattern of medulla, plagmentation

2. Color of cortex, types of scales

3. Curliness of the cuticle

What type of microscope allows side by side viewing of two different hairs

Comparison microscope

What type of microscope can provide incredible detail of the surface or interior of the sample, magnifying the object 50,000 times or more

Electron microscope

What type of microscope can indicate the presence of a dye or other treatment

Fluorescence microscope

In order to test hair for chemicals and drugs, what must you do first

Dissolve hair in solvent to break down keratin and release substance

How can an investigator calculate the length of time during which a person was taking drugs or ingesting other toxins

Testing different parts of hair

What test can identify up to 14 different elements in a single two-centimeter-long strand of human hair

Neutron Activation Analysis

When can hair be tested for DNA?

If hair is forcibly removed from a victim or suspect, the entire hair follicle (called a follicular tag) may be present.