Human Hair
What is the average number of hairs on a human head?
Approximately 250,000 hairs.
What are the three layers of a hair shaft?
Cuticle, cortex, medulla
How should hair be collected from a crime scene?
Using gloves or forceps, and placing it in a suitable container.
What is the role of the papilla in hair growth?
It supplies nutrients to the hair.
How can hair indicate racial background?
By microscopic characteristics unique to different racial groups.
What is the main purpose of hair in mammals?
To regulate body temperature and provide insulation.
What pigment gives color to black hair?
Eumelanin
Why shouldn't hair be cut during collection?
It may lose important characteristics for forensic analysis.
What indicates that hair is from an animal?
A medullary index of 0.5 or greater.
What is the appearance of the medulla in human hair?
Generally absent or fragmented.
What type of evidence is hair classified as?
Class evidence
How does hair vary in texture?
Hair can be coarse or fine, depending on various factor
What is secondary transfer in hair evidence?
When hair is transferred from one surface to another.
How can chemical tests on hair reveal drug use?
They can detect traces of drugs absorbed in the hair.
What can cause hair to appear brittle?
Chemical treatments such as bleaching.
What happens to hair during the telogen stage?
The hair follicle is dormant, and hairs are easily lost.
What is the medullary index used for?
To distinguish between human and animal hair.
What should you do if hair is attached to an object?
Leave it intact and wrap the object for transportation.
What is a follicular tag?
The entire hair follicle attached to a forcibly removed hair.
How can hair color be determined?
By the type and amount of melanin present in the cortex.
How can hair help in drug testing?
Hair can show traces of drugs or toxins absorbed by the body.
What can the shape of the hair cross-section indicate?
It can influence the curl of the hair.
What kind of envelope is best for storing hair samples?
Paper bindles or coin envelopes, sealed in larger envelopes.
How can neutron activation analysis assist in forensic investigations?
It can identify multiple elements in a hair sample, linking it to individuals.
Why is it important to collect 50 hairs from a suspect?
To account for variability in hair characteristics.