Human Hair

Class or Individual?

Human

Hair as Evidence

Human Hair

100,000

50-100

trail

growing

class

root (follicle)

DNA

30

Hair can be different on different areas of the scalp.

In General...

Round

oval

Flat

Round

What is the color of your hair?

00:20

Hair Shafts have 3 layers. They are made of ____________ which makes the hair _________ and ________.

Keratin

Flexible

Strong

Medulla

• Cylinder of air down the center of the hair
• Might look like it isn't there
• only if its the same color as the cortex

Cortex

• This is the biggest part of the hair.
• Gives hair color with melanin.
• Darker hair = more melanin

Cuticle

• These protect and make hair waterproof.
• They overlap like shingles on a roof.

CUTICLE DESCRIPTION

Coronal cuticle- looks like cups or crowns stacked on top of each other.

• There are three different _______ that can be found on the outside of hair.
• Each is made up of ________.
• These are what we ____ when we look at hair.

patterns

Imbricate - Flattened, random overlapping scales.

protein

Spinous -longer, pointed scales.

see

Pigment Granule Distribution

Describing the Cortex

Smooth

• Grainules are not obvious

Granular

• Obvious granules- look like pencil dots

Spotty

• large dark blobs scattered throughout

Cuticles are made of melanin.

Describing the Cortex

Light BrownMedium Brown Dark Brown

Cortex Color Choices

Clear /Gray Light Yellow Medium Yellow Red

Describing the Medulla

Describing the Medulla

A microscope is used to determine the __________________of hair. This is useful for comparing to suspect hair.

646

imagine

side

side

diameter

Hair can also be used to test for drug use!

Finding Diameter