Hair Anatomy and Identification Quiz

The central canal present in many hairs, located in the medulla.

The medullary index is calculated by dividing the medulla diameter by the total hair diameter. Human hair typically has a medullary index of less than 0.33, while animal hair often has a higher index.

Hair shafts have three main layers: medulla, cortex, and cuticle. The medulla is the innermost layer, the cortex contains pigment, and the cuticle is the outermost protective layer.

The most significant feature for identifying the species of a hair sample is the pattern of scales on its surface.

Hair color is determined by the distribution and type of pigment granules found within the cortex layer of the hair shaft.

The cuticle is the outermost layer of the hair shaft and is highly resistant to chemicals and decomposition.

The morphology of hair or fibers refers to their physical characteristics, such as color, shape, and diameter. For fibers, it also includes the shape of their cross-section.

Rayon is a type of regenerated fiber, meaning it's derived from cellulose, a natural polymer.

Qiviut is a luxurious and exceptionally warm natural fiber obtained from the undercoat of musk oxen.

To preserve fiber evidence properly, it should be packaged using a druggist fold technique.

Automobile carpet fibers often have a trilobal cross-section, which means they have three lobes or rounded edges.

Cellulose is the primary component of wood, providing its structure.

Mohair and cashmere are luxury fibers obtained from goats. Mohair comes from the Angora goat, while cashmere is sourced from the cashmere goat.

Cotton is the most common natural plant fiber used globally, known for its versatility and affordability.

When collecting fiber evidence, it's essential to avoid cross-contamination to ensure the integrity of the samples.

In the case of Wayne Williams, carpet fibers from his home were found on two victims, and fibers from his car connected him to the crime scene, providing strong evidence of his involvement.

Before the 20th century, all fibers used for clothing and other purposes were natural fibers, such as cotton, wool, and silk. Synthetic fibers, like nylon, and regenerated fibers, like rayon, were only developed in the 20th century.