Hair Anatomy
Hair Anatomy:
Hairs are dead structures that are made of a hardened protein called keratin and grow out from follicles. Most of the body is covered with hairs, with the exception of the palms of the hands and the soles of the feet. They help to keep the body warm and are also a form of protection. The eyelashes prevent substances from entering the eyes, and the hairs that line the nose and ears help to trap dust and bacteria.
There are three types of hair that are found on the body:
Vellus Hairs:
Soft, fine downy hairs found all over the body with the exception of the palms of the hand, soles of the feet, lips and eyelids. They are usually non-pigmented depending on ethnicity.
Terminal Hairs:
Thicker coarse hairs that are highly pigmented and designed to protect, as in the case of the eye lashes, which protect from the sun and from objects entering into the eye. They can also be found on the head, inside the nose, brows, under arms, legs and pubic region.
Intermediate Hairs:
These develop from vellus hairs during puberty and are deeply rooted, pigmented and coarse. They’re the type of hair that’s often removed from unwanted areas.
The three primary layers of hair are the:
- Cuticle
- Cortex
- Medulla
THE CUTICLE:
This outermost layer of the hair and is made of keratin. Under a microscope, it looks like a series of overlapping scales. Keratin is extremely hard and durable and its main function is to protect the inner layers of the hair, If the hair is over-processed the cuticle will become damaged and the health of the hair is compromised.
THE CORTEX:
This middle layer of the hair is made of large elongated cells containing melanin, giving the hair its colour. The cortex also contains moisture and therefore is reliant on the cuticle to maintain hydration levels in the air.
THE MEDULLA:
The innermost layer is made of cells that form a shaft up the middle of the hair. It serves no particular function and is often lacking in the fine vellus hairs.
Eyelash Anatomy:
Each eyelid contains eyelashes and each is anchored into a root hair plexus. Unlike normal hairs, this gives eyelash hairs extra sensitivity, meaning they can cause the eye to reflexively snap closed if a foreign body reaches the eye. Eyelashes tend to graduate in length, being longest towards the centre of the eye and shorted towards the outer corners.
From a lash technician’s perspective, it’s important to note that the lashes on the upper lids and lower lids are actually quite different from one another. Upper lid lashes tend to be thicker, longer, more numerous and curve in an upwards direction. The lashes on the lower lid, by contrast are shorter and can have little or no curve.
Every eyelash hair consists of three main regions and three primary layers. The main regions are the roots, shaft and tip.
Root:
The part that grows in the follicle. It is the widest part of the eyelash.
Shaft:
The middle length of the eyelash. It is where the eyelash begins to taper
Tip:
The end of the eyelash, the point at which it is at its thinnest.
The Lash Lifecycle:
A thorough understanding of the lash lifecycle is vital. All human hair, including eyelashes, follows three distinct phases:
- Anagen
- Catagen
- Telogen
The Anagen Phase:
The growth phase is also referred to as the anagen phase. This is the phase when the lashes are actively growing and it can last between 30 and 45 days, only about 40% of the upper lashes and 15% of the lower lashes are in the anagen phases at any one time. Each eyelash will grow to a specific length and then stop.
Catagen Phase:
The transition phase is also known as the catagen phase. During this phase the lash stops growing and the hair follicle shrinks. If an eyelash falls out or is plucked out during the phase, it will not grow back right away because the follicle needs to complete the catagen phase before it can move onto the next one.
Telogen Phase:
The Telogen phase is also referred to as the resting phase. This phase can last more than 100 days before the eyelash falls out and a new one begins to grow because each individual eyelash is in its own phase of the life cycle, it is normal for a few eyelashes to fall out here and there across many days. It typically takes between 4 and 8 weeks to fully replace an eyelash.
Lash Tint Theory:
Tinting the lashes can be very effective especially on fair lashes, the tips on everyone’s lashes are usually fair, and this can make them appear shorter than they actually are. Benefits of tinting will make them look bolder and longer.
How tinting works:
Tint contains molecules of dye called toluenediamine. The molecules need to be activated in order to tint the lashes, hydrogen peroxide activates tint and this is referred to as developer. Hydrogen Peroxide is a chemical that contains oxygen and activates chemical reactions. This opens up the cuticle layer of the lash, tint molecules penetrate into the cortex. Smaller dye molecules join with hydrogen peroxide forming large molecules that become trapped in the cortex of the hair.