Hair and Fibers

Question 1

What is trichology?

Answer 1

the study of hair and scalp health

Question 2

What is the function of hair?

Answer 2

Protection (Eyelashes)
Heat Regulation
Warmth

Question 3

Follicle

Answer 3

Actively growing root or base of the and containing DNA and living cells

Question 4

The hair shaft is composed of what protein?

Answer 4

Keratin

Question 5

Name the three layers of the hair shaft.

Answer 5

Inner medulla
Cortex
The outer cuticle

• Like a pencil
• Yellow is cuticle
• Wood is cortex
• Graphite is medulla

Question 6

Which section of hair has pigment?

Answer 6

Cortex

Question 7

What are the five medulla patterns

Answer 7

continuous
Interrupted
Fragmented
Solid
none

Question 8

Difference between Interrupted and Fragmented

Answer 8

Fragmented has no structure to where it is broken while interrupted is structed

Question 9

What is the Anagen

Answer 9

• First stage of the hair life cycle
• Hair actively grows
• Cells around the follicle rapidly divide and deposit materials in the hair

Question 10

What is the Catagen

Answer 10

• Second stage of hair life cycle

- Hair grows and changes

Question 11

What is the telogen

Answer 11

• Third and final stage

- Follicles become dormant

Question 12

Contrast Animal and Human hair.

Answer 12

Animal hair is denser toward the medulla
Banded color pattern
 - Possible in animals (zebras)
 - Not in humans
The medulla is much thicker in animals

Question 13

Why is hair evidence useful in forensic science?

Answer 13

• Chemical tests can provide a history of drugs and other toxins, nutritional deficiencies
• When the follicle is present, DNA may be obtained
• Hair does not easily decompose, it has a tough outer layer

Question 14

Why is it important for CSI’s to collect 50 hairs from a suspect?

Answer 14

• For constantly among hair threads and each hair may have a different medulla. You can do more tests.
• Hairs on an individual may vary

Question 15

How can hair be both class and individual evidence?

Answer 15

Hair is class evidence if there is no follicle because there is no DNA while it is individual evidence if there is a follicle because of the DNA the follicle has.

Question 16

Define fiber.

Answer 16

the smallest unit of a textile material that has a length many times greater than its diameter

Question 17

Why is it important to collect fibers within the first 24 hours?

Answer 17

Collecting fibers within 24 hours is critical

95% of fibers fall or are lost

Question 18

Describe tests that can be conducted on fibers.

Answer 18

Nondestructive methods are used when there is only one strand of the fiber
- Microscopes reveal character’s shapes and marking
- Infrared spectroscopy
Destructive Testing Methods can be used when large samples are present (ONLY LARGE SAMPLES)
- Burning fibers
- Dissolving fivers in various liquids

Question 19

Why are different tests conducted for different amounts of fibers found at a crime scene?

Answer 19

If you have one fiber then you can’t do destructive testing such as burning because then you lose the evidence.

Question 20

What is yarn?

Answer 20

Yarn is spun thread used for knitting, weaving, or sewing.

Question 21

What are natural fibers?

Answer 21

Fibers that come from animals, plants, or minerals.
Examples include:
- Wool and silk from animals
- Cellulose and cotton from plants
- Fiberglass and asbestos from minerals

Question 22

What are synthetic fibers? Give an example of synthetic fiber.

Answer 22

Synthetic fibers are man-made fibers derived from cellulose.

Rayon is an example of synthetic fiber.

Question 23

Difference between Solid and continuous

Answer 23

Continous is just a single line while solid takes up the whole hair.