Hair

Question 1

What does the human hair consist of?

Answer 1

follicle and shaft

Question 2

Shaft

Answer 2

can see
mitochondrial DNA
contains keratin

Question 3

Follicle

Answer 3

can not see
mitochondrial and nuclear DNA
cells and blood vessels

Question 4

When is hair individual evidence?

Answer 4

DNA - except identical twins

Question 5

Hair is a type of

Answer 5

trace evidence

Question 6

If hair is left behind it is…

Answer 6

Locard’s principle of exchange

Question 7

Why do we have hair?

Answer 7

regulates temperature
decreases friction
protects skin against UV light
acts as a sense organ

Question 8

The hair shaft

Answer 8

made of keratin, a protein that make hair strong and flexible

Question 9

Three layers of the hair shaft

Answer 9

medulla (inner)
cortex
cuticle (outer)

Question 10

The cuticle

Answer 10

a transparent outer layer of the hair shaft
scales point toward end of hair, revealing younger and older ends of hair
in human hair, overlapping scales are flat and narrow = imbricate

Question 11

The cortex

Answer 11

largest part of hair shaft
contains most of melanin in hair
distribution and size of pigment granules vary from person to person

Question 12

The medulla

Answer 12

center of hair

can be pigmented or unpigmented

Question 13

Six types of hair

Answer 13

head hair
eyebrows and eyelashes 
beard and mustache hair
underarm hair
body hair 
pubic hair

Question 14

Hair varies from region to region on the..

Answer 14

body of the same person

Question 15

Four phrases of the hair growth cycle

Answer 15

Catagen
Telogen
Exogen
Anagen

Question 16

Anagen

Answer 16

the state in which hair grows
.5 inches per month on average
short phrase: stress, poor diet, and aging

Question 17

Catagen

Answer 17

the period of time in which the hair detaches from the blood vessels and dermal papilla
lack of oxygen and nutrients
lasts for two weeks

Question 18

Telogen

Answer 18

hair detached and resting in skin

last three months

Question 19

Exogen

Answer 19

an extension of the telogen characterized by the shedding of telogen hair

Question 20

Bleaching

Answer 20

lightens hair by oxidizing pigment
makes it brittle
can disturb scales on cuticle 
artificial = sharp line
natural (bleaching from the sun) including the cuticle and cortex

Question 21

Dyeing

Answer 21

dye stains entire hair including the cuticle and cortex

can use growth rate of hair (.44 mm per day on average) to calculate time since death

Question 22

Pattern of pigmentation

Answer 22

Human: pigmentation is denser toward the cuticle
Animal: pigmentation is denser toward the medulla

Question 23

Medulla

Answer 23

Animal: is thicker in animals to provide insulation
Greater than or equal to .5 = animal
Less than or equal to .5 = human

Question 24

Cuticle patterns

Answer 24

Imbricate = like overlapping roof tiles; humans
Coronal = like stacked crowns; mice
Spinous = like spines or petals; cats

Question 25

Collecting hair in an investigation

Answer 25

plucking
shaking
scraping
using tape
vacuum

Question 26

Macroscopically

Answer 26

look at length, color, and curliness

Question 27

Mircoscopically

Answer 27

medulla pigmentation pattern, cortex pigmentation, and types of cuticle scales
measure meduallary index

Question 28

Because hair grows out of the skin anything ingested or absorbed through your skin

Answer 28

food, water, drugs, toxic substances

Question 29

Analysis can reveal

Answer 29

a person’s travels, their diet their drug intake, and toxin

Question 30

The more melanin present in the hair

Answer 30

the more binding of drugs such as cocaine and morphine

Question 31

Washing of hair does not eliminate the drugs through

Answer 31

anything that destroys the pigment will decrease binding of the drugs