forensic science chapter 3 review

What factors are used to calculate the medullary index of the hair

width of the medulla and the width of the hair

Neutron activation analysis can check hair for the presence of

DNA

Why is hair considered class evidence

It cannot be traced back to a single person unless you don't have the root which has the DNA

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 two ways that animal hair differs from human hair

The pattern of pigmentation can vary widely different in animals. Human hair is usually one color while animal hair can change color abruptly and in a branded pattern.

The body of a woman was found in the woods. Some hair fibers found on the body was sent to the crime lab for analysis. The ends of the hair attached to the body was grey, 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 that hair grows at the rate of 0.44 mm per day, on approximately what date did the women die? Explain your answer

The woman probably died around the date of August 18th

Which of the following is most likely a result of hair bleaching

a yellowish tint to the hair

All hairs on the head of a person are identical

false

Hair is composed of a protein called cellulose

false keratin

Human hair has which type (s) of cuticle

imbricate

calculate the medullary index of a hair whose diameter is 100 microns wide and whose medulla measures 58 microns. Is this a human or animal hair

it is an animal hair

the hair shaft is composed of the cuticle, cortex, and

medulla

Which part(s) of a hair can be analyzed for DNA

root

Although variations can occur, which of the following best describes northern European hair

straight with evenly distributed granules

Describe the structure of hair. Include in your answer the terms follicle, medulla, cortex, and cuticle

the follicle is a club-shaped structure in the skin. The cuticle is a transparent outer layer of the hair shaft. The cortex is the part of the hair that contains most of the pigment granules that give the hair its color. The center of the hair is the medulla.

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. It is important to pull them because if you cut them then you won't get the hair follicle and the hair follicle has the DNA they need. B- why is it necessary to obtain 25 to 50 hairs from this woman? This woman denied 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 of drugs for over one year

It is important to pull them because if you cut them then you won't get the hair follicle and the hair follicle has the DNA they need This woman denied that she is currently taking drugs and states that she stopped using drugs a year ago Chemicals that the skin absorbs can be incorporated into hair. Testing different parts of the hair it may be possible to establish a timeline for when exposure to poisons or other toxins might have occurred. This doesn't prove she's guilty because it just places her at the scene and could be circumstantial

he period of active hair growth is called the _________ stage

anagen

Which of the following characteristics is found in typical Asian hair

dark medulla

The cuticle scales of the hair always point toward the

tip of the hair

The cortex may contain pigment granules

true

The shaft of the hair is considered class evidence in a trail.

true