Hair and Fingerprints

Hair shafts have 3 major structures. List each structure:

1. cuticle

2. cortex

3. medulla

Where is the Cuticle found in the hair shaft and what is its function

Cuticle- Outermost layer, protects inner layer from damage (UV rays, products, etc)

Where is the cortex found in the hair shaft and what is its function

Cortex- thick middle layer of the hair shaft, directly beneath the cuticle and surrounding the innermost medulla. Provides essential strength, elasticity, color, and texture.

Where is the medulla found in the hair shaft and what is its function

Medulla- Innermost soft, and fragile core layer of the hair shaft, typically found in the center of thick or coarse hair. It is often absent in fine or blonde hair. The medulla acts as a central marrow or pitha-like structure, potentially contributing to thermal insulation and hair volume.

What is keratin and where is it found in the human body?

Structural protein that acts as a primary building block for nails, hair and skin.

What is a hair shaft compared to a hair root?

A hair shaft is the part of your hair you can see above the skin

A hair root is the part of your hair below the surface of the skin

What is this fingerprint?

Arch

What is this fingerprint?

Whorl

What is this fingerprint?

Loop

What is this fingerprint?

Tented arch

What is a minutiae?

Minutiae are the tiny, specific details and discontinuities within a fingerprint's ridge pattern—primarily ridge endings and bifurcations (forks)—used to uniquely identify individuals.

What is a latent fingerprint and how does it differ from a patent fingerprint?

A latent fingerprint is an invisible impression left on a surface by natural sweat and oils, requiring physical or chemical enhancement to be seen.

Patent fingerprints are instantly visible to the naked eye, usually made by contaminants like ink or blood

What is a twelve point match in regards to fingerprints?

A traditional forensic standard where a fingerprint examiner identifies at least 12 matching "minutiae" or unique ridge characteristics between a latent crime scene print and a known suspect print.

Why are fingerprints left when you touch a surface? What causes the print to be “left behind”?

The friction ridges on our fingertips constantly secrete natural oils and sweat, which are transferred to any surface touched. These residues form invisible "latent" prints, which reproduce the unique, ridged patterns of the skin.