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L-3 Forensics Hair Analysis PowerPoint Presentation
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L-3 Forensics Hair Analysis

L-3 Forensics Hair Analysis

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L-3 Forensics Hair Analysis

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  1. L-3 Forensics Hair Analysis

  2. Hair and Forensics • Considered class evidence. • Easily transferred. • Does not decompose and maintains chemical stability. • When follicle present, DNA is obtainable.

  3. The Structure of Hair • 2 parts: Follicle and Shaft • The follicle is a club-shaped structure in the skin. • At the end of the follicle is a network of blood vessels that supply nutrients to feed the hair and help it grow. This is called the papilla. • Around the papilla is a sebaceous gland called the bulb which secrets oil to condition. • Nerves are wrapped around the follicle that make hair stand up when environments change.

  4. Structure of Hair • Made up of three layers: • Inner Medulla • Cortex • Outer Cuticle

  5. The Cuticle • Transparent outer layer of the hair shaft. • Made up of scales that overlap to protect from the inner layers of hair.

  6. Cortex • Made up of cells. • Largest part of the hair shaft. • Contains the pigment granules (melanin) that give the hair its color.

  7. Pigment Granuels

  8. Types of Medulla • The center of the hair is called the medulla. • It can be a hollow tube or filled with cells, fragmented, segmented, continuous or even doubled.

  9. Treated hair shows different characteristics. Dye is found in cuticle and cortex. Bleaching gives a yellow tint when examined. If found at a crime scene, simple math can determine the last time it was colored. • Great differences between animal and human hair. • Key physical characteristics can identify race. • Analysis can also determine the location of where a hair may have come from on the body.