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Chapter 5: Hair “For three days after death, hair and fingernails continue to grow but phone calls taper off.” Britain CSI Link —Johnny Carson Comedian.

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Presentation on theme: "Chapter 5: Hair “For three days after death, hair and fingernails continue to grow but phone calls taper off.” Britain CSI Link —Johnny Carson Comedian."— Presentation transcript:

1 Chapter 5: Hair “For three days after death, hair and fingernails continue to grow but phone calls taper off.” Britain CSI Link —Johnny Carson Comedian and television host

2 Kendall/Hunt Publishing Company1 Hair Analysis a. hair is class evidence b. hair can be used to back up circumstantial evidence c. hair absorbs (takes in) and adsorbs (when molecules of different substance hold onto each other) substances both from within the body and from the external environment 1. Introduction:

3 Kendall/Hunt Publishing Company2 2. Human Hair can determine a. one of the most frequently found pieces of evidence at scene of violent crime. b. can provide a link to criminal c. From hair, one can determine: 1.If source is human or animal 2.Race (sometimes) 3.Origin of location (body/scalp/pubic) 4.Whether hair was forcibly removed 5.If hair was treated with chemicals 6.If drugs have been ingested

4 Kendall/Hunt Publishing Company3 Skin Structure (cool pix)

5 Kendall/Hunt Publishing Company4 Skin Structure (cool pix)

6 3. The nature of Hair Basics a. grows from the papilla and is made up of dead cells. b. Its basic components are keratin (a protein), melanin (a pigment), and trace quantities of metallic elements. c. These elements are deposited in hair during growth and/or absorbed from external environment.

7 4a. Hair Life Cycle 1) Anagen (active growth) actively growing, materials are deposited in the hair shaft by cells found in the follicle (lasts up to 5 years) 2) Catagen (transition) hair follicle shrinks to about 1/6 th normal diameter. “Root" is diminished and dermal papilla breaks away and rests (stays) below scalp. 3) Telogen (dormant) follicle is dormant or resting. Hair that is dying and ready to fall out; (lasting two to six months)

8 b. Growth & Length 1) about 0.5 mm/day or 1 cm/month (.5 inch/month ) 2) 100 head hairs are shed each day 3) On a healthy head, a) 80% to 90% hair follicles in anagen phase b) 2% in catagen phase c)10% to 18% in telogen phase 7 4. Hair Life Cycle

9 Kendall/Hunt Publishing Company8 5. Hair Shaft

10 Kendall/Hunt Publishing Company9 a. The Cortex Made of keratin, gives hair its shape. It has three major characteristics : 1) Melanin— pigment granules give hair color 2) Cortical fusi— air spaces, usually found near root but may be found throughout hair shaft 3) Ovoid body– largest of the cortex granules (a sub layer of the cortex)

11 Kendall/Hunt Publishing Company10 b. Cuticle Scales This is the outermost layer of hair, covered with overlapping scales. These scales point toward the tip of hair. Scales differ between species of animals, scales are named based on their appearance. Write down these three basic patterns: Coronal Spinous Imbricate

12 1) Coronal Scales Commonly found in the hairs of small rodents and bats Rarely in human hairs Looks like a crown, right? Coronal means crown-like Kendall/Hunt Publishing Company11

13 2) Spinous Scales Found at proximal region (close to root) of mink hairs and fur hairs of seals, cats, some other animals. NEVER found in human hairs Kendall/Hunt Publishing Company12 Bat hair

14 3) Imbricate Scales Commonly found in human hairs and many animal hairs Kendall/Hunt Publishing Company13

15 Kendall/Hunt Publishing Company14 hair core, not always visible. The medulla comes in different types and patterns. Human Medulla

16 Kendall/Hunt Publishing Company15 c. The Medulla c. The Medulla Types:  Intermittent or interrupted  Fragmented  Continuous  Stacked or  Absent—not present

17 What are the 3 parts of the hair shaft? Label your notes… Kendall/Hunt Publishing Company16 Cuticle Cortex Medulla

18 Kendall/Hunt Publishing Company17 6. Hair Comparison Characteristics a.Color, and color intensity of pigment granual b. Bleached (color removed), leaving a yellow tint. c.Length d.Cut – how the hair was cut, razor or scissor

19 Kendall/Hunt Publishing Company18 Cut Determination Newly cut? Older hair? Hair becomes rounded with time Now, add this to your notes: Draw this picture and label it

20 RAZOR CUT HAIRSCISSOR CUT HAIR BROKEN HAIRBURNED HAIR Interesting to note:

21 Kendall/Hunt Publishing Company20 7. DNA from Hair a. Only the root contains nuclear DNA. If hair is forcibly removed, some folicular tissue may be attached containing DNA. b. The hair shaft contains abundant mitochondrial DNA, inherited only from the mother. c. mtDNA can be typed by comparing sample to relatives if no DNA from the body is available. It is more difficult and costly than using nuclear DNA.

22 Kendall/Hunt Publishing Company21 8. Sex Determination a. treated hairs are more frequently encountered in females b. Sex (gender) can be determined from removed hair (with folicular tissue) c. nuclear DNA and mitochondrial DNA (mtDNA) tests will provide more specific information regarding possible origin of hair.

23 Kendall/Hunt Publishing Company22 Fun Fact: Hair Toxicology  Napoleon died in exile in 1821. By analyzing his hair, some investigators suggest he was poisoned by deliberate administration of arsenic; others suggest it was vapors from the dyes in the wallpaper that did him in.

24 Kendall/Hunt Publishing Company23 9. Race Determination Examiners differentiate between hairs of; Caucasoid (European ancestry), Mongoloid (Asian ancestry) Negroid (African ancestry)

25 Kendall/Hunt Publishing Company24 a. Negroid (African) Hairs are curly or kinky, Flattened cross section; can appear curly, wavy, or coiled. Pigment granules are larger and clumped of diff. sizes and shapes. Density of pigment may be so great as to make the hair opaque Twisting of the hair (buckling) can be present, hair frequently splits along the length.

26 Kendall/Hunt Publishing Company25 b. Caucasoid (European) Hairs are fine to medium coarseness, Generally straight or wavy Colors range from blonde to brown to black. Hairs vary from round to oval in cross section fine to medium-sized, evenly distributed pigment granules.

27 Kendall/Hunt Publishing Company26 c. Mongoloid (Asian) coarse, straight, and circular in cross section, wider diameter than the hairs of the other racial groups. cuticle, is usually significantly thicker medulla is continuous and wide. cortex, contains pigment granules generally larger in size; often appear to be grouped in patchy areas within the shaft.

28 Kendall/Hunt Publishing Company27 Human Medulla may be continuous, fragmented or absent.

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