U1 - Hair & Fiber

Trace Evidence

Small but measurable amounts of physical or biological material found at a crime scene

Nothing

The first thing you do at a crime scene

Loop

Whorl

Arch

Double Loop

Radius

Smaller bone in the forearm on the same side as the thumb

Ulna

Larger bone of the forearm, attached at the wrist and located on the side of the little finger

Locards Exchange Principle

Every contact leaves a trace

Impression Evidence

Includes toolmarks, tire tracks, shoe prints, and bite marks

Mixture

Combination of two or more substances that are not chemically combined

Compound

Substance formed by the chemical combination of two or more elements in definite proportions

Solution

Mixture that forms when one substance dissolves another

Solute

Substance that is dissolved

Solvent

Substance in which the solute dissolves

Universal Solvent 

Water - due to its polarity and ability to dissolve many different solutes

Chromatography

Technique used to separate the components of a mixture based on the tendency of each component to separate when moving through another material

Hair Follicle 

Small tubular cavity containing the root of a hair 

Hair Root

The part of the hair located below the surface of the epidermis

Epidermis

Outer layer of skin

Hair Cuticle

Outermost layer of hair composed of overlapping scales

Hair Cortex

Intermediate layer of hair that is protein-rich and contains pigment

Hair Medulla 

Central core of a hair

Medullary Index

Ratio of the diameter of the medulla to the diameter of the entire hair 

Keratin 

Protein that is the principal component of hair, skin, and nails 

Pigment

Chemical compound that reflect certain wavelengths of visible light given a substance its color

Mitochondrial DNA

Found in the powerhouse of the organelle; can be retrieved from rootless hair and narrow to a group of people with the same maternal lineage 

Lineage

Group claiming a common ancestor

Organelle

Cell structure that carries out a specific function within the cell

Plant-Based Natural Fibers

Cotton, linen, and rayon

Animal-Based Natural Fibers

Silk and wool

Cotton, Linen, Wool

Harder to ignite, slow to burn

Silk, Rayon, Synthetic

Burns easily