the+study+of+hair-+rebecca

 Important vocab words : 1. **class evidence :** Material that connects an individual of thing to a certain group. 2. **comparison microscope:** a compound microscope that allows the side by side comparison of samples, such as hair of fibers. 3. **Cortex :** the region of a hair located outside of the medulla containing--- 4. **Cuticle**: the tough outer covering of a hair composed of overlapping scales 5. **hair follicle:** the actively growing root or base of hair containing DNA and living cells . 6. **individual evidence :** a kind of evidence that identifies a particular person or thing 7. **Keratin :** a type of fibrous protein that makes up the majority of the cortex of a hair . 8. **medulla** : the central core of a hair fiber 9. **melanin granules :** bits of pigment found in the cortex of a hair 10. **neutron activation analysis :** a method of analysis that determines composition of elements in a sample. 11. **trace evidence :** small but measurable amounts of physical or biological material found at a crime scene.

An investigator finds a blond hair at a crime scene.
 * Intro summary:**

- hair is considered class evidence - the investigator can only use the hair to identify a group or class of people -**ex:** if a blond hair is found, the investigator can rule out all Asians and African people - only able to compare the blond hair with a blond suspect - physical characteristics of hair can offer clues to the broad racial background of the individual -hair can: adhere to clothes, carpets, and many other surfaces and can be transferred to other locations- this is called secondary transfer - secondary transfer is most common with animal hair - without follicle cells attached, the hair cannot be used to identify a specific individual. -the follicle possesses DNA - DNA leads to individual identification which is individual evidence. - Hair is useful to the crime scene because of its tough outer coating that cannot be easily decomposed
 * Information about hair that pertains to the crime scene:**

- hair analysis can provide trace evidence in a criminal investigation - Sydney Smith first used a comparison microscope to performe side by side analysis of hair collected from a crime scene in 1934 - which helped solve a murder of a 18 year old girl -today hair analysis includes neutron activation analysis and DNA fingerprinting and is considered a standard tool in trace evidence analysis. -NAA or neutron activation analysis is a process that tests for the presence and concentration of various elements in a sample. NAA showed that hair found in a crime scene contained a ration of sulfur to phosphorus that was similar to the victim's found hair. At the trial the suspect confessed to the murder in light of the hair analysis results. This was the first time NAA hair analysis was used to convict a criminal.
 * history of hair analysis:**

- all mammals have hair - hairs main purpose: to regulate body temperature and to keep the body warm by insulation - hair is used to decrease friction, to protect against sunlight, and to act as a sense organ - hair can be very dense which is referred to as fur. - hair works as a temperature regulator in association with muscles in skin: if it is cold outside, then muscles pull the hair strands upright, creating pockets that trap air- trapped air provides a warm insulating layer next to the skin. If it is warm outside, the muscles relax and the hair becomes flattened against the body releasing trapped air. -when humans are born they have about 5 million hair follicles, only 2 percent of which are on the head. - as a human ages, the density of hair decreases
 * function of hair:**

Hair consist of two parts: - the follicle is a club shaped structure in the skin. At the end of the end of the follicle is a network of blood vessels that supply nutrients to feed the hair and to help it grow. - this is called the PAPILLA - surrounding the papilla is a bulb. A sebaceous gland, which secretes oil that helps keep the hair conditioned, is associated with the bulb. The erector muscle that causes the hair to stand upright attaches to the bulb. - Nerve cells wind around the follicle and stimulate the erector muscle in response to changing environment conditions. - the hair shaft is composed of the protein <span style="color: rgb(9, 154, 11)">KERATIN which is produced in the skin. Keratin is made up of a chain of amino acids that forms a helical, or spiral shape. These helices are connected by strong bonds between amino acids. these bonds make hair strong. the hair shaft is made up of three layers: an inner medulla, a cortex, and an outer cuticle. A good analogy for the structure of a hair shaft is the structure of a pencil: the painted yellow exterior of the pencil is similar to the cuticle. The graphite in the middle of the pencil is similar to the medulla. The wood of the pencil is analogous to the cortex of a hair. Human hair has cuticle scales that are flattened and narrow also called <span style="color: rgb(9, 134, 32)">IMBRICATE. Animal hair had different types of cuticles.
 * The structure of hair:**

The cuticle is a transparent outer layer of the hair shaft. - it is made out of scales that over lap one another and protect the inner layers of the hair - when examining a section of hair under a microscope, noticing the direction of scales point shows the younger and older ends of the hair. - cuticles can determine the presence of different drugs toxins or metals at a specifies point in time. - human hair has cuticle scales that are flattened and narrow, also called <span style="color: rgb(7, 146, 32)">IMBRICATE
 * Cuticle:**

- the cortex is the largest part of the hair shaft. - it contains the most of the pigment granules (melanin) that give the hair color - the pigment distribution varies from person to person - if your pigment is large, your cortex will have uneven color distribution when viewed under a compound microscope.
 * Types of Cortex:**

- the center of the hair is called the <span style="color: rgb(3, 135, 23)">medulla. - it can be a hollow tube, or filled with cells. -some people do not have a medulla, and some people have a fragmented one or segmented one, or some even have a double medulla - medulla contains pigment granules or lacks pigments. -forensic investigators classify hair into 5 different groups depending on the appearance of the medulla.
 * Types of Medulla**

<span style="color: rgb(8, 130, 28)"> Continuous: One unbroken line of color Interrupted (intermittent) Pigmented line broken at regular intervals <span style="color: rgb(7, 136, 25)"> fragmented or segmented : Pigmented line unevenly spaced <span style="color: rgb(3, 114, 15)"> solid : Pigment area filling both the medulla and the cortex none No separate pigmentation in the medulla
 * Medulla Pattern: Description:**

- hair can vary in shape, length, diameter, texture, and color - the cross section of the hair may be circular, triangular, irregular or flattened, influencing the curl of the hair. - hair can be coarse(whiskers) or fine(children) - some furs are a mixture as in dogs coats, which often have 2 layers: one fine and one coarse - hair color varies depending of the pigment granules distribution and on hair dyes that may have been used. - hair varies from person to person - not all hairs on someone's head are exactly the same -suspects have have grey hairs along with brown hair - therefore 50 hairs are collected from the suspects head. Typically 25 hairs are collected from the pubic region.
 * Types of Hair:**

- <span style="color: rgb(114, 19, 205)">6 types of hair on the human body : 1. head hair- usually circular or elliptical in cross section 2. eyebrows and eyelashes- also circular but often have tapering ends 3. beard and mustache hair- tends to be think and triangular- beard hair is usually coarse and may have a double medulla 4. underarm hair 5. auxiliary and body hair- oval or triangular 6. pubic hair- oval or triangular - each hair type ha sits own shape and characteristics - you can determine where the hair came from on the body by looking at the cross sectional shape. - hair from the arms and the legs usually have blunt tips
 * Hair from different parts of the body:**

Hair proceeds though three stages as it developes: 1. stage one is called <span style="color: rgb(3, 130, 25)">ANAGEN STAGE and last approximately 1,000 days. 80- 90 percent of all human hair is in the anagen stage. This is when the hair is in active growth when the follicle are rapidly dividing and depositing materials within the hair. 2. <span style="color: rgb(3, 160, 27)">The CATAGEN STAGE: the hair grows and changes color: to gray. contains about 2 percent of all hair growth and development. 3. <span style="color: rgb(7, 151, 35)">TELOGEN STAGE: hair is dormant or resting and hairs are easily lost. about 10- 18 percent of all hairs are in the telogen stage.
 * The Life Cycle of Hair:**

- bleaching hair removes pigment granules and gives hair yellowish color. It also makes hair brittle and can disturb the scales of the cuticle. -Dyeing hair changes the color of the hair shaft. - you can determine when the hair was last color- treated-- hair growth will determine that. -
 * Treated Hair:**

- Animal hair and human hair have several differences including the pattern of pigmentation, the medullary index, and the cuticle type. - Animal pogments are often found in solid masses called OVOID BODIES, especially in dogs and cattle - human hairs are usually one color along the length. - Animal hairs can change color abruptly in a banded pattern. - in animals, the medulla is much larger than in humans - The ration of the diameter of the medulla to a diameter of the entire hair is know as the <span style="color: rgb(3, 165, 40)">MEDULLARY INDES. If the medullary index is 0.5 or greater the hair came from an animal. If the medullary index if 0.33 or less, the hair is from a human.
 * Animal hair and Human Hair:**

- transfers of materials will occur when two objects are in contact with each other - Locards exchange principle - if someone is at a crime scene, he or she will leave some trace of his or her presence behind, or pick up some trace evidence from the crime scene - <span style="color: rgb(5, 168, 18)">trace evidence = HAIR - investigators collect trace evidence at a crime scene - hair can be collected by: plucking, shaking, and scraping surfaces. It can also be collected by playing tape over a surface so that the hair sticks to it. - when surfaces are large, you can vacuum the surface to pick up hairs - investigators will compare the hair found to the 6 major body regions to to determine if the suspect is a match. - you must determine if the hair is animal or human hair.
 * Using hair in an investigation:**

hair viewed for forensic investigations is studied both macroscopically and microscopically. - length, color and curliness are macroscopic characteristics - microscopic characteristics are the patter of the medulla, pigmentation of the cortex, and the types of scales on the cuticle. -medullary index can be measured - most viewing can be between 40 and 400 times - a comparison microscope is what the microscope is called - fluorescence is a microscope that is equipped with filters to detect the fluoresce light, indicating the presence of a dye or other treatment
 * Microscopy:**

- substances can get into your hair like lead, drugs or toxins, so an investigator can take a hair and dissolve it in an organic solvent that breaks down the keratin and releases any substance that have been incorporated into the hair. - you can determine when the person did the toxins or the drugs because hair does not decompose quickly, so hair allows a timeline for you. - human hair grows about 1.3 cm per month - NEUTRON ACTIVATION ANALYSIS (NAA):- can identify up to 14 different elements in a single two- centimeter- long strand of human hair - the probability of the hairs of two individuals having the same concentration of nine different elements is about one in a million.
 * Testing for Substances in the hair shaft:**

- follicular tag: blood and tissue attached to the follicle may be analyzed - the blood proteins can be isolated to identify the blood type of a suspect. - DNA analysis can also preformed on hair follicle cells. - DNA analysis of the hair follicle provides an identification with a high degree of confidence, whereas analysis of the hair shaft usually provides class evidence only. - if a microscopic match between a suspect and a sample is found, then the sample will be forwarded for blood and DNA testing
 * testing the hair follicle:**


 * QUICK SUMMARY:

addies page:** -secondary transfer-hairs from other surfaces, clothes,carpets, and animal hair -hair offers answers to racial backgrounds or physical characteristics -a follicle of hair gives DNA which is individual evidence, leads to individual identification -hair is trace evidence

Hair-all mammals have hair to keep them warm, regulates body temperature -protect against sunlight, decrease friction, and to act as a sense organ -cold temperatures-small muscles pull hair strands upright which creates pockets that track air -the trapped air provides a warm insulating layer next to the skin -when warm, hair is flattened against body and air is released

Trichology is the study of hair -A forensic examiner just by looking at hair can tell scale patterns, roots, color, length, shaft characteristics and more. -they can tell if hair was "forceably removed, damaged by burning, dyed or bleached, and cut by glass" -can figure out if the person was ill -however a microscopic look cannot tell the owner -people have different hair characteristics - a microscopic exam gives evidence that hair samples are with a certain person -the hair root has to have tissue in order to have DNA to tell of the exact owner

Quiz- http://www.fbi.gov/page2/march05/hair031605.htm

Hair Microscopy- -analayzing hair under a light microscope involves two steps -identifying the hairs and comparing them to the known hairs -to determine whether two or more individuals could have come into contact with one another The Hair examination process: the first step is to determine whether the hair is animal hair or human hair -if animal hair, what animal -the regions of the body that hair is most useful in the crime scene is the head and pubic areas -longer hairs are more important to the crime scene than shorter because they have more characteristics to compare and "the greater variation along the length, the greater the degree of significance" -fingerprints are always the best identification tool -however research has shown that hair from two different individuals is distinguishable

liz's page: __Describe & Introduce:__

Hair does not decompose easily because of a tough outer coating. Human hair grows approximately 1.3 cm per month Hair is found on all animals, it is often called fur. Its purpose is to insulate the body, protect the body, and regulate the temperature of the body. When a hair is found on a crime scene it can provide information concerning the race and the background of a suspect. A single hair can hold many different variations of a persons background, drug use, nutritional facts, and hold other chemicals an individual has been exposed to By chemically testing a hair an investigator can look for any of these clues to help determine a suspect

Hair found on a crime scene can be considered
 * Class Evidence** or **Individual Evidence**

If it is Class Evidence it cannot be used to specify an individual because the follicle is not attached. By identifying the type or color of the hair you can use that information to eliminate people belonging to a race or group that does not share the characteristics of the hair found. You can also use it to compare or link a suspect having similar characteristics belonging to the hair. It cannot directly link a suspect to the hair even if they appear similar.

If it is Individual Evidence the follicle is still in tact on the hair. DNA of the suspect can be determined and can link the hair to the individual.

In the late 1800's scientists began to recognize the significance of hair as trace evidence

The reason that hair is important in crime scene investigation is because in each person hair can have many different characteristics, that even without DNA can link or narrow down suspects. It can vary in color, texture, length, diameter and shape. The cross section can be different, it can be circular, irregular, triangular, or flattened, this determines the curl, wave or straightness of the hair. Hair can have many different textures younger people generally have softer more fine hair and older people have tough or coarse hair. Investigators can immediately tell if a hair has been dyed when they look at a strand under the microscope. One person may have many different hairs on their head, one strand may not categorize every strand on that persons head. An investigator will usually take at least 50 hairs from a suspects head due to the variation of colors and types. (25 are usually collected from the pubic region) Ex. someone who's hair is turning gray

__Different parts of the body:__ One person has six types of hair on their body, each type can be distinguished by the shape of their cross section: Head hair- circular or elliptical cross section Eyebrow and Eyelash hair- circular cross section, generally have tapering ends Beard and Mustache hair- Triangular cross section, usually thick or even have a double medulla Underarm hair- Oval or triangular cross section Body hair- Oval or triangular cross section, arm and leg hair have blunt tips and are often frayed at the ends Pubic hair- Oval or triangular cross section

__Hair develops in 3 different stages:__
 * Anagen** stage (growing)- lasts the first 1,000 days, 80-90% of hair is in this stage
 * Catagen** stage(growing and developing)- is when the hair is changing and growing, it is responsible for 2% of the growth and development of hair
 * Telogen** stage(dormant) - hairs are easily lost during this stage because it is the final stage in which hairs are finished growing, 10-18% of hair on a humans head are in this stage

__Identify various parts of hair:__ There are two main parts of hair: The Follicle and the Shaft. The Follicle is the part that is located in the skin, it is attached to blood vessels that hold body nutrients and help the hair grow. The Shaft is made completely out of protein, this protein is called Keratin, this protein makes the hair strong and flexible. The Shaft has three layers: The Medulla is located inside of the hair. It is a tube that runs in the center, this tube is filled with cells or in some cases can be hollow. Scientists can use the medulla to make 5 different categories to classify a strand of hair under. This is because the medulla can change from person to person, the tube can once again be filled with cells or hollow, absent, fragmented, segmented, or it can be doubled or continuous, it can also have pigment or have no pigmented. The Cortex is in the center of the strand. It is the largest part of the shaft and it holds the majority of the melanin (pigment granules) and gives off the majority of the color. The amount of pigment in a hair differs from person to person and can be looked at under the compound microscope. The Cuticle is located on the outside of the hair, it is the thin outer layer. It protects the inner layer of the hair because it is made of scales that overlap each other. These scales can help in an investigation because a scientist can determine the age of a certain part of the hair by looking at which way the scales are pointing. When chemically testing for drugs, toxins or metals present in the hair, they can then specify the point in time in which the person was exposed to such things.

Different treatments one goes about putting on their hair tampers its original form Bleaching hair makes it brittle and can change the aligning of the scales on the cuticle. It makes the hair turn yellow and removes pigment. ' Dying hair will change the color of the hair shaft, cuticle and cortex. A scientist can usually distinguish a naturally colored hair and a dyed hair. A scientist can take a color treated hair and determine the last time it has been dyed. They take the length of hair that is naturally colored and divide it by 1.3 (cm hair grows per month), and they can estimate or determine how many months the hair has gone un dyed. This can help to identify a suspect or victim in a crime.

__Destingish between human and non human hair:__ Investigators can determine weather a hair is human or animal using a low power compound microscope by looking for some major differences: <span style="color: rgb(8, 155, 22)"> Human and animal hair have many differences Pattern of pigmentation: Pigmentation in human hair is denser at the cuticle, and animal hair pigmentation is denser toward the medulla <span style="color: rgb(4, 134, 31)"> Human hair generally maintains one solid color while animal hair are found in solid masses (ovoid bodies), and have banded patterns that often change abruptly Medullary index: The medulla in humans is smaller than in animals Cuticle type:

__Methods used to investigate hair found on a crime scene:__ Locards exchange principle: Whenever two objects are in contact, some transfer of material will occur. If a person is at a crime scene there is a very likely chance that they will leave trace evidence, a very common example of trace evidence is hair.

Hair is collected from a crime scene by: Plucking surfaces or fabrics Shaking items Scraping surfaces Using tape to extract Large surfaces can sometimes use a small vacuum They carefully try and collect hairs directly from the place which they are found to avoid cross contamination.

When there are many hairs found on a crime scene or victim Investigators will take samples of hair from the 6 sources of hair on the body of the victim These hairs will be investigated, determined if human, and then compared.

When a hair is found, investigators will look at it macroscopically and microscopically. <span style="color: rgb(199, 0, 68)">**Macroscopically** : They can see the length, color and curliness <span style="color: rgb(164, 10, 100)">**Microscopically** : They look at the types of scales found on the cuticle, the cortex pigmentation, and the medulla pattern and length

Magnification in a microscope for viewing hair is between 40 and 400 times

__Techniques Using Microscopes:__ <span style="color: rgb(211, 3, 86)">**Phase contrast microscopy**: This technique is useful for viewing small details in a hair, especially in translucent hairs. This is possible by using a compound microscope with special parts and lenses allows light to pass through the hair and allow for certian details and information to be seen that couldnt be seen using the comparison microscope. <span style="color: rgb(204, 0, 116)">**Fluorescence microscope** : This is useful when a hair that has been treated or dyed is found. When a fluoresced light is shined on a dye or chemical found on a hair it will change or appear a particular color that is different, this can let them determine what was used on the hair. <span style="color: rgb(158, 0, 77)">**Electron Microscope**: Electron microscopes can magnify the hair over 50,000 times. This is very useful in looking at fine and tiny details on the surface or on the interior of the hair. This is possible by applying a beam of direct electrons at the hair.
 * <span style="color: rgb(215, 4, 93)">Comparison microscope :** Very useful and common for hair analysis, it allows the scientist to view two different hair samples at the same time, it has two separate parts for each, this is important and useful when trying to compare a hair found on a scene to a hair of a victim or suspect.

__Techniques For Investigating a Hair:__ <span style="color: rgb(168, 0, 78)">**Chemical Analysis:** Investigators use this method to determine the history of drug use, see toxins they have recently been exposed to or ingested. Scientists can also determine if a victim was poisoned. When a hair grows, it collects chemicals that the skin has absorbed. This process is done by releasing substances that the hair has been exposed to by dissolving the hair in an organic solvent that breaks down the keratin. They can then use the length of the hair and the rate of growth to determine a time line for the hair in order to see when it was exposed to the substance found on it.
 * Neutron Activation Analysis**:

Important words & Vocab:

__Definitions__: <span style="color: rgb(189, 10, 97)">**Class Evidence** : Material that connects an individual or thing to a certian group. <span style="color: rgb(163, 0, 78)">**Comparison Microscope** : A compound microscope that allows the side-by-side comparison of samples, such as hair or fibers <span style="color: rgb(35, 11, 11)"><span style="color: rgb(197, 2, 68)">**Cortex**: The region of a hair located outside of the medulla containing granules of pigment <span style="color: rgb(255, 0, 173)">**Cuticle** : The tough outer covering of a hair composed of overlapping scales <span style="color: rgb(214, 0, 142)">**Hair Follicle**: The actively growing root or base of a hair containing DNA and living cells <span style="color: rgb(248, 42, 137)">**Individual Evidence**: A kind of evidence that identifies a particular person or thing <span style="color: rgb(221, 8, 135)">**Keratin**: A type of fibrous protein that makes up the majority of the cortex of the hair <span style="color: rgb(251, 65, 163)">**Medulla**: The central core of a hair fiber <span style="color: rgb(248, 42, 176)">**Melanin Granules**: Bits of pigment found in the cortex of a hair <span style="color: rgb(244, 52, 204)">**Neutron Activation Analysis**: A method of analysis that determines composition of elements in a sample <span style="color: rgb(252, 3, 171)">**Trace Evidence**: Small but measurable amounts of physical or biological material found at a crime scene

NAA- Neutron Activation Analysis - Process that tests "for the presence and concentration of various elements in a sample" of hair

Examples of how topic is important in crime solving:

Gaetane Bouchard, 16 year old girl body found in 1958 had many strands in her hand, Using NAA thaey determined that the ratio of sulfer to phosphorus was closer to vollman, a suspect in the crime, than her own hair.This evidence was used to convict a Vollman, (first time in history NAA hair analysis was used to convict a criminal in a court case)

Determine if two examples of hair are likely to be from the same person:

Calculate medullary index for hair:

Distinguish hairs from individuals belonging to the broad racial categories: (Chapter 3: The study of hair)


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comparison microscope


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