forensic chapter 3 vocab/review

bleaching hair

- disturbs the scales on the cuticle -removes pigment -leaves hair brittle and yellowish

continuous medullary pattern

1 unbroken line of color

double medulla hair ex

beard/mustache

telogen

follicle becomes dormant

spinuous cuticle

resemble petals

coronal

stack of crowns

cuticle

the tough outer covering of a hair composed of overlapping scales

alfred swaine taylor and thomas stevenson

Covered hair in a forensic science text

calculate the medullary index of a hair whose diameter is 110 microns wide and whose medulla measures 58 microns/ s this a human or animal hair

To decide if this hair is a human hair or a nonhuman animal hair, we need to calculate the medullary index. The medullary index has the following formula : 58/110 The medullary index is 0.527 Now, the medullary index for humans is 0.33 or less while the medullary index for animals is 0.50 or greater. ⇒ ⇒ animal hair

comparison microscope

a compound microscope that allows the side-by-side comparison of samples, such as hair or fibers

individual evidence

a kind of evidence that identifies a particular person or thing

neutron activation analysis

a method of analysis that determines composition of elements in a sample

which of the following is most likely a result of hair bleaching? a. increased number of disulfide bonds b. a yellowish tint to the hair c. a more triangular cross section d. thickened scales on the cuticle

a yellowish tint to the hair

neutron activation analysis can check hair for the presence of a. silver b. dna c. water content d. hair dye

silver

difference of animal and human hair

size of medulla, animals can have banded hair and different cuticle patterns, animal is denser toward medulla and human toward the cortex

trace evidence

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

which factors are used to calculate the medullary index of the hair? a. scale diameter of cuticle and the length of the hair b. width of cortex and the width of the medulla c. length of entire hair and the pattern of pigmentation d. width of medulla and the width of the hair

width of medulla and width of the hair

keratin

a type of fibrous protein that makes up the majority of the cortex of a hair

tapered hair

eyelash and eyebrows

t or f: hair is composed of a protein called cellulose

false; keratin

catagen

hair grows and changes

buckled hair ex

pubic region

solid medulla pattern

pigmented area filling both the medulla and the cortex

interrupted medullary pattern

pigmented line broken at regular intervals

fragmented medullary pattern

pigmented line unevenly spaced

phase contrast microscope shows

presence of dye or other treatments

chemical tests test for

presence of various substances

victor balfhazard and marcelle lambert

published a comprehensive study of hair

function of hair

regulates body temperature, decreases friction, protects against sunlight

which parts of a hair can be analyzed for dna? a. root b. cuticle c. medulla d. cortex

root

dying hair

colors the cuticle and the cortex

imbricate

commonly flattened and narrow

neuron activation analysis tests for

concentrations of substances

which of the following characteristics is found in typical Asian hair? a. dark medulla b. sparsely distributed pigment granules c. flattened cross section d. hair is curly

dark medulla

crime scene investigators collected hair from a dead person's body. one of the first things that needs to be established is if this hair is human or animal. describe 2 ways that animal hair differs from human hair.

examine the cuticle type the medullary index and the pattern of pigmentation of the 2 hairs: animal has more variations in the cuticle type, which includes the coronal and spinous types, a thicker medullary index than humans moreover the pigmentation in the animal hair is denser near the medulla, whereas the pigmentation in human hair appears denser toward the cuticle

t or f: all hairs on the head of a person are identical

false; they're different

characteristics in asian hair

flattened cross section

anagen

hair actively grows, cells around the follicle rapidly divide and deposit materials in the hair

why is hair considered class evidence?

hair is considered class evidence because it can't be used to identify specific individuals

a follicle embedded in the skin produces the

hair shaft

blunt hair ex

body hair

human hair has which types of cuticle? a. imbricate b. spinous c. coronal d. pigmented

imbricate

shape

influences the cut of the hair

3 layers of hair

inner medulla, cortex, outer cuticle

macroscopic investigations indicate

length, color, curliness

class evidence

material that connects an individual or thing to a certain group

the hair shaft is composed of the cuticle, cortex, and a. medulla b. root c. crown d. granules

medulla

cortex

thickest layer, contains most pigment, denser near cuticle

A woman with long hair is a suspect in a burglary case. At the crime scene, several long hairs were found attached to a broken lock of the safe. The police obtain a warrant and request a sample of 25 to 50 hairs from this woman. They tell the woman it is important that they pull the hairs from her head rather than to merely cut the hairs. The police suspect that the woman was stealing to help support a drug habit. a. Why is it important that the police pull the hairs from her head rather than cut her hair? b. Why is it necessary to obtain 25 to 50 hairs from this woman? c. The woman denies that she is currently taking drugs and states that she stopped using drugs a year ago. Explain how the police can determine if the woman has been off drugs for over one year. d. Suppose the hairs of the woman match the hairs found at the crime scene. Why does this not necessarily prove that she was the guilty party?

a. It is important that the hairs are pulled rather than cut as DNA is found in the hair follicle which is located under the scalp. This is where the hair gets it's blood supply. If there are any drugs in the person's system, traces of it will go into the hair shaft from the blood supply by the hair follicle. b. It's necessary because hair doesn't grow constant or consistent and 25 to 50 hairs are needed for an accurate test. This decreases false positive results. c. The hair drug test can go back to about 90 days to see if she has been clean within that time. Beyond that, interviews with family and friends would also be helpful. Phone records would also show if there has been any contact with a dealer. d. This doesn't prove she's guilty because it just places her at the scene and could be circumstantial.

the period of active hair growth is the __________ stage a. catagen b. telogen c. anagen d. imagen

anagen

3 stages of hair

anagen, catagen, telogen

dr. sydney smith

analyzed hairs side by side

melanin granules

bits of pigment found in the cortex of a hair

cross section

circular, triangular, irregular, flattened

texture

coarse or fine

The body of a woman was found in the woods. Some hair fibers found on the body were sent to the crime lab for analysis. The ends of the hair attached to the body were gray, but the tips of the hair showed that it had been dyed. The distance from the root of the hair to the beginning of the dyed area measured 8 mm. Investigators determined that the victim's hair had last been dyed on August 1, 2004. Assuming the hair grows at the rate of 0.44 mm per day, on approximately what date did the woman die? Explain your answer.

step 1: a. hair was shown to be dyed; ends were gray b. distance from hair root to starting point of dyed area is 8mm c. victim's hair last dyed august 1, 2004 step 2: a. hair measurement distance from root to the dyed area ----------------------------------------------------------- 1.3 (hair growth) step 3: a. 0.8cm ---------- 1.3cm approx. 0.62 months step 4: 1 month 0.62 months ----------= ---------------- 4 weeks x weeks cross multiply and solve x=approximately 2.48 weeks step 5: use s calendar and 2 weeks from august 8 2004 =august 28 2004 so she died approximately 2 and half weeks august 28 2004

although variations can occur, which of the following best describes northern european hair? a. kinky with dense. unevenly distributed pigment b. straight with evenly distributed granules c. round cross section with a large diameter d. coarse with a thick cuticle and a continuous medulla

straight with evenly distributed granules

hair follicle

the actively growing root or base of a hair containing DNA and living cells

medulla

the central core of a hair fiber

describe the structure of hair include in your answer the terms follicle, medulla, cortex and cuticle

the hair consists of 2 parts a follicle and a shaft. a follicle is a network of blood vessels that supply nutrients. the hair shaft is made up of 3 layers, the inner layer medulla, a cortex, and an outer cuticle. the cuticle is the outer coating composed of overlapping scales. the cortex is a protein-rich structure containing pigments. the medulla is the central core and it may be absent

cortex

the region of a hair located outside of the medulla containing granules of pigment

examining a hair shaft tests for

timeline for exposure to toxins

the cuticle scales of the hair always toward the a. root b. medulla c. tip of the hair d. folicle

tip of the hair

t or f: the cortex may contain pigment granules

true

t or f: the shaft of the hair is considered class evidence in a trial.

true