Forensics Chp.3 Unit 2

Morphology

hair color and structure

Cuticle

scale-like structure that covers the exterior of the hair - imbricate (humans), coronal, spinous

Cortex

in cuticle, pigment (color) found, made of spindle-shaped cells

Medulla

collection of cells that look like a central canal running through the hair

Anagen

initial growth (up to six years - more likely to get DNA)

Catagen

slower growth stage (2-3 weeks)

Telogen

hair is pushed out, falls out naturally

Ways to determine where hair came from

• Age (infants)

• Gender (DNA only)

• Race

How many hairs should be collected in a crime scene?

25 hairs (minimum) from the head and pubic areas

Store in envelope

Natural fibers

animal and plant, most commonly used is cotton

Synthetic fibers

natural/synthetic polymers

Polymers

large number of atoms usually arranged in repeating patterns