So, what is it and why do we have it?
Various studies show that other than self-expression, and attracting a suitable mate (looking at you, admiring yourself in the mirror), hair is said to aid in the regulation of the owner’s body temperature with the use of air pockets within the innermost layer of the fiber, this layer is called the medulla. [1]
As a matter of fact, our strands are comprised of three layers. [2]
They Include:
Cuticle
- The transparent protective layer that we can feel.
- The cuticle is characterized by overlapping cells in a scale-like formation on the outer layer of the strand.
- They resemble the scales on a snake and are composed of the same protein as the cortex.
Cortex
- Shielded by the Cuticle in healthy strands.
- The cortex is identified as the middle layer which makes up the majority of the fiber and is mainly composed of a protein known as “Keratin”. This protein gives hair its strength and structure.
- The cortex is also home to the color pigment known as “Melanin” which gives hair its natural color.
- Moisture is stored in the cortex.
Medulla
- Surrounded by the cortex.
- The medulla is identified as the innermost layer of the fiber.
- Only found in thick and/or coarse hair.
Where are the three layers of the strand found?
These 3 layers of the strand also known as the hair shaft are what we can see and feel above the skin. The fiber you comb, cut, or color. They are mostly comprised of a tough Protein. The toughness of the protein is a result of hardened (dead) cells – keratinization.
Regulation of hair growth
Within the skin, there is a whole other ecosystem that regulates hair growth. Thanks to this ecosystem, your growth happens cyclically from an organ known as the follicle. The follicle is also home to other tissues that contribute to the development of hair into the strands we see and feel. [3] [4] [5]
A few ways hair is used
Within the follicle, special stem cells are fed by vessels that enable cell division, leading to hair growth. This is one reason hair is considered a source of information because it contains DNA, which can be used to establish paternity, or as evidence in the investigation of a crime. Some studies show that parts of the fiber may also serve as an indicator of the nutritional or even mental health of an individual. [6] [7]
Summary
In summary, hair is regarded as a keratinous fiber that grows from an organ within the skin and consists of three layers known as the cuticle, cortex, and medulla. Hair may be used as a form of communication, self-expression, identifier, or even a temperature regulator.
