Hair and Fiber Analysis Ms. Faulconer

Methods of Fiber Analysis: Write all Methods of Fiber Analysis: Physical Methods Microscopic Analysis Size Color curvature Chemical Methods React with various chemicals (acids, organic solvents, etc.) Look for melting, disintegration, discoloration, curling

Types of Fibers Natural Synthetic (polyester, nylon, etc.) Write all Types of Fibers Natural Animal (wool, fur, etc.) Vegetable (cotton) Synthetic (polyester, nylon, etc.) Blend (mixture)

SEM Comparison Cotton Wool

Wool

Hair Evidence Standard Students will demonstrate the ability to collect, preserve, and identify evidence found at a crime scene. Objectives 1. Describe the cuticle, cortex, medulla, and root of hair. 2. Explain the distinction between animal and human hairs. 3. List hair features that are useful for the comparison of human hair. 4. Explain the proper collection of hair evidence.

The Biology of Hair Write bold An appendage of the skin that grows out of an organ known as the hair follicle. Extends from its root or bulb embedded in the follicle, continues into a shaft, and terminates at a tip end. Hair follicle: sac-like anatomical structure from which hair grows. Sebaceous gland: gland that secretes sebum, which lubricates the skin and hair. Arrector pili muscle: muscle that elevates the hair. Root of hair: part of the hair implanted in the dermis. Papilla: part of the hair connected to the conjunctival tissue. Inner root sheath: sheath formed of several layers of cells. Connective tissue sheath: girdle enclosing the epithelial sheath and connecting to the conjunctival tissue. Epidermis: outer layer of the skin. Hair shaft: a filament that grows from the skin.

Write all The Shaft of Hair Composed of three layers: cuticle, cortex, and medulla.

Cuticle of Hair Write bold Outside covering of hair that resists chemical decomposition. Formed by overlapping scales that point towards the tip end of the hair. Scales are made from hardened/keratinized cells that come from the follicle. Cuticle of a healthy hair. The scales lie flat, and are covered with oil, making the hair feel smooth and look glossy. The scales make the hair stiff, and protect the inside A hair with a damaged cuticle, perhaps from brushing, coloring, or blow-drying. The hair looks dull, and scales flaking off may expose the inner layers, leading to further damage.

Cortex of Hair Found within the cuticle. Write bold Cortex of Hair Found within the cuticle. Made of spindle-shaped cortical cells aligned parallel to length of hair. Within the cortex are pigment granules made by melanocytes that give hair its color. Cortex of a damaged hair. A split end, caused when a hair shaft is pulled apart. Many split ends give hair a frizzy appearance, and cause tangles.

Your natural Hair color is determined by three factors Write all Your natural Hair color is determined by three factors 1. The type of natural color pigment melanin present in your hair's cortex. Eumelanin (black pigment) Phenomelanin (red/yellow pigment) 2. How many melanin granules exist 3. Whether those granules are close together or far apart The process of pigmentation consists of three phases: activation, synthesis, and expression. The first step is the activation of the melanocyte by one of several triggers that begins the enzymatically-mediated synthesis of the melanin, starting with the amino acid tyrosine. In other words, the activation phase occurs when the melanocytes receive some sort of stimulus that causes them to go into a defensive mode and begin the melanin production process. Melanocytes are activated by a variety of stimulants: stress, acne, hormones, and inflammatory processes such as exposure to UV radiation or other free radical damage. All these factors trigger the cells in the upper part of the skin to produce a variety of small chemical “messengers,” called hormones, and more specifically melanocyte stimulating hormone (MSH). These hormones then travel to where melanocytes are located and activate the melanocyte production of melanin. Also smoking, thyroid imbalances, and vitamin B12 deficiencies can turn hair grey.

How Melanin pigments determine your natural haircolor: Write all Color Pigment (s) Packing Black Eumelanin Dense Brown Both Loose Blonde Red Phenomelanin

What causes gray hair? Write bold As you age, your natural production of pigment slows down and your natural color loses its color strength. This doesn't happen to every hair at the same time, so the contrast between the hair with no color and the hair that still has some color causes it to look gray. So how gray your hair actually looks is determined by the percentage of strands with no color vs. the pigmented strands.

Write all Medulla of Hair Collection of cells that look like a canal running through a hair. Not all hairs have medullae Can be classified as continuous ( most animals, human rare (except Asians)), fragmented (some animals, human) or absent (human).

Medulla Shape Humans and most animals cylindrical Write bold Medulla Shape Humans and most animals cylindrical Other animals  patterned (ex. Cat medulla looks like string of pearls, Deer medulla looks like round cells occupying the entire hair shaft)

Examination of the Medulla

Patterns in Animal Species Examination of Scale Pattern

Human Hairs Racial Determination Body Area Age and Sex? Forcibly Removed?

Write bold Racial Determination Usually wavy or curly, containing dense, unevenly distributed pigments. Cross section is flat to oval in shape. Asian descent Usually coarse containing pigment granules larger in size than Caucasians. Cross sections are round in shape. African descent Cross section varieties. Usually straight or wavy with very fine to coarse pigments that are more evenly distributed . Cross section are oval to round in shape. European Descent

Head Hairs Long with moderate shaft diameter and diameter variation Write bold Head Hairs Long with moderate shaft diameter and diameter variation Medulla absent to continuous and relatively narrow when compared to the structure of hairs from other body areas Often with cut or split tips Can show artificial treatment, solar bleaching, or mechanical damage Soft texture, pliable

Pubic Hairs Shaft diameter coarse with wide variations and buckling Write bold Shaft diameter coarse with wide variations and buckling Medulla relatively broad and usually continuous when present Root frequently with tag Tip usually tapered, rounded, or abraded Stiff texture, wiry

Limb Hairs Diameter fine with little variation Write bold Diameter fine with little variation Gross appearance of hair is arc-like in shape Medulla is discontinuous to trace with a granular appearance Soft texture Tips usually tapered, often blunt and abraded, rounded scale ends due to wear

Facial Hairs (Beard/Mustache) Write bold Facial Hairs (Beard/Mustache) Diameter very coarse with irregular or triangular cross-sectional shape Medulla very broad and continuous, may be doubled

Chest Hairs Shaft diameter moderate and variable Write bold Shaft diameter moderate and variable Tip often darker in color, long and fine, arc-like Medulla may be granular Stiff texture

Axillary or Underarm Hairs Write bold Resemble pubic hairs in general appearance, but less wiry Diameter moderate and variable with less buckling than pubic hairs Tips long and fine, frequently with bleached appearance

Other Body Hairs Eyebrow: Stubby, some diameter fluctuation, saber-like in appearance Eyelash: Short, stubby with little shaft diameter fluctuation, saber-like in appearance Trunk: A combination of features of limb and pubic hairs, a transitional hair

Tip of the Shaft Burned Cut Razored Split

Root of Hair Provide the tools to produce hair and continue its growth Write bold Provide the tools to produce hair and continue its growth 3 Stages of Growth (different looking roots) Anagen -initial phase, root is flame shaped Catagen –transition phase (2-3 weeks), root is elongated Telogen –phase where hair naturally falls out of the skin, root is club-shaped

Hair Growth Cycle

Forcibly Removed? Pulled Forcibly Removed Shed

Brushed-out hairs all have this kind of root. A normal telogen hair with a hard 'club' end, seen under (left) a light microscope and (right) an electron microscope This is an anagen hair, one which was pulled out and not ready to be shed. An anagen hair that has been plucked out: notice the soft, sticky tail

Collection of Hair Evidence

Collection of Hair Evidence Write all Collection of Hair Evidence Questioned and Reference hair must come from same area of the body; one cannot, for instance compare head hair to pubic hair. The collection of 50 full length hairs from all areas of the scalp will normally ensure a representative sampling of head hair.

Collection of Hair Evidence Write bold Collection of Hair Evidence A minimum collection of 24 full length pubic hairs should cover the range of characteristics present in this type of hair. All collected hairs must be full-length so that the investigator can see if the color and morphological features vary throughout the length of the hair.

Packaging of Hair Evidence Write bold Packaging of Hair Evidence Recover all hair present. If possible, use fingers or tweezers to pick up hair, place in paper bindles or coin envelopes which should then be folded and sealed in larger envelopes. Label the outer sealed envelope.

Packaging of Hair Evidence Write all If hair is attached, such as in dry blood, or caught in metal or a crack of glass, do not attempt to remove it but rather leave hair intact on the object. If the object is small, mark it, wrap it, and seal it in an envelope. If the object is large, wrap the area containing the hair in paper to prevent loss of hairs during shipment