HAIR ANALYSIS

Hair Follicles

Structures from which hair grows in humans.

Locard's Exchange Principle

Every contact leaves a trace of evidence.

Forensic Scientist

Expert who analyzes physical evidence in investigations.

Types of Hair

Six distinct categories based on body location.

Head Hair

Hair growing from the scalp.

Eyebrow and Eyelash Hair

Short, fine hair found around the eyes.

Beard and Mustache Hair

Facial hair typically found on men.

Underarm Hair

Hair located in the armpit region.

Auxiliary or Body Hair

General term for body hair excluding pubic.

Pubic Hair

Hair found in the genital region.

Hair Characteristics

Physical traits help identify hair origin.

Buckling in Pubic Hair

Distinctive feature indicating specific hair type.

Double Medulla

Unique structure found in beard hair.

Frayed Ends in Arm Hair

Indicates wear or damage to hair tips.

class evidence

material that connects an individual or thing to a certain group

comparison microscope

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

cortex

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

cuticle

the tough outer covering of a hair composed of overlapping scales

hair follicle

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

individual evidence

a kind of evidence that identifies a particular person or thing

keratin

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

medulla

the central core of a hair fiber

melanin granules

bits of pigment found in the cortex of a hair

neutron activation analysis

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

trace evidence

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

hair structure

Hair consists of two parts: a follicle and a shaft

papilla

where a network of blood vessels supply nutrients to feed the hair and help it grow

hair shaft

contains keratin which makes hair strong and flexible and is made of amino acids

Locard's Exchange Principle

the concept that every contact leaves a trace

human hair cuticle scales

flattened and narrow known as imbricate

cortex pigment

contains the pigment melanin which gives hair its color

fun fact about hair follicles

When humans are born they have 5 million hair follicles, only 2 percent of which are on the head

formation of hair follicles

All of the hair follicles in humans are formed when a fetus is five months old

functions of hair

Keep body warm, Protect against sun, Sense organ

Hair Follicles

Structures from which hair grows in humans and animals.

Locard's Exchange Principle

Every contact leaves a trace; evidence is exchanged.

Chemical Analysis

Detects toxins in hair by breaking down keratin.

Toxins

Harmful substances like arsenic and lead found in hair.

Timeline of Exposure

Determined by testing hair segments for toxins.

Average Hair Growth Rate

Hair grows approximately 0.44 mm per day.

DNA Analysis

Identifies individuals if entire hair follicle is present.

Organic Solvent

Used to dissolve keratin for chemical testing.

Ingested Toxins

Substances absorbed into hair from consumption.

Locard's Exchange Principle

Every contact leaves a trace of evidence.

Medullary Index

Ratio of medulla diameter to hair diameter.

Animal Hair

Denser and larger medulla compared to human hair.

Human Hair

Medullary index is 0.33 or less.

Cattle Hair

Medullary index is 0.33 or less.

Cuticle Type

Shape and structure of outer hair layer.

Pattern of Pigmentation

Distribution of color in hair strands.

Hair Follicles Development

Formed when fetus is five months old.