2) Hair Fiber- consist of three layers: medulla, innermost core, cortex. The medulla is only found in mature thick hair.
Epidermal derived cells close to the (DP) remain undifferentiated cells called matrix cells. Their main function is on multiplication and proliferation to produce more cells. The cells produced in the middle of the hair follicle become part of the hair fiber itself. These are cortex cells. The continuous production of these cells push upwards towards the surface of the epidermis (skin). During this process they differentiate into particular cell types. The cortex cells change from a round appearance to that of a more flattened appearance. They are then squeezed together into layers (lamella)
If the follicle contains melanocyte cells, melanin pigment is incorporated into the cortex cells. These cells will then keratinize and harden. It then becomes impossible for them to function and they die. They are then pushed away from the hair bulb region and upwards as new cells appear from behind. The cortex has now become part of the keratinized hair fiber. This is how hair grows. Even more important is the role of cells in the development of hair. The incorporation of stem cells ensure that this process remain healthy and functional.
Some large hair follicles contain a central strand of
cells which are loosely organized and not packed together.
This tube located in the very center of the hair is known
as the medulla.
The cuticle is located around the outside of the hair fiber.
This layer consist of more keratinized cells. They are
however, arranged in a slightly different way to the cortex
cells. During the production of the cuticle cells, they lay over
the cortex cells and flatten into an overlapping fashion. They progressively become more flattened over time. The cortex cells cannot function after becoming keratinized and thus die.
Hair is comprised of up to 95% keratin protein. A protein is comprised of a chain of amino acids bonded together in a specific sequence to form a specific protein.
Hair has 18-23 different amino acids with cystine accounting
for as much as 4% of the protein which in turn will account for
up to 90% of the hairs overall strength. 2 amino acids join
together through a "peptide bond".
The colour of the hair depends on 2 other proteins found in hair
most commonly known as melanin. Melanin accounts for 1% of the
hairs composition. Eumelanin will cause hair to be brown-black
where phaeomelanin will account for blonde-red. The absence of either type produces white/gray hair.
The alpha helix is the descriptive term given to the polypeptide chain that forms the keratin protein or human
hair. It is a coiled structure where the amino acids link together to form the coil. There are approximately 3-6
amino acids per turn of the helix "coil". Each amino acid is connected together by a "peptide bond".
The peptide bond is located between the carbon atom of one of the amino acid extending bond with the
nitrogen atom of the next amino acid.
3) Root Sheaths- This is the surrounding 2 layers of the hair fiber. Outer Root Sheath (ORS) and Inner Root Sheath ( IRS)
Outer Root Sheath (ORS) forms the outermost layer of the epithelium while the (IRS) is below the (ORS) and closest to the hair fiber. The arrector pili muscle is located in the "buldge" region of the (ORS) and this muscle is connected to the epidermis
(skin) at the opposite end. This muscle allows your
hair to stand erect.
The sebaceous gland also extends from the (ORS)
It comprises a few cells that produce oils (lipids/fats)
These cells are large with cytoplasm filled vacuoles
containing lipids. They are often divided into several
lobes of the sebaceous duct. This duct has a single
opening into the tube where the hair fiber sits. The (ORS) surrounds the hair fiber and the (IRS) deep into the dermis. The (ORS) tapers and ends just above the bulb region containing the (DP). It comprises several layers of cells identified with unique ultra structural properties.
1) Derma Papilla ( DP)- This is the precursor to the hair follicle. It is a "pear" shaped structure found at the base of the follicle. It consists of fibroblast cells derived from the mesoderm. Fibroblast cells are the most common cells of connective tissue and they are highly active. The suffix "blast" is used in cellular biology to denote the stem cell or cell in an activated state of essential that these stems maintain a healthy existence to ensure proper hair development. These cells are held close to the base of the epidermal derived cells. The epidermal derived cells produce the hair fiber and root sheaths. A thin layer called the basement "membrane", " lamina" or glossy "membrane" separates the (DP) cells from the hair fiber/sheath cells. Extensive research is being conducted to see the ability of the induced stem cells to this region can regenerate new hair growth.
This membrane divides the cells descendent from the
embryonic ectoderm ( epidermis) and embryonic mesoderm.
This barrier plays a major role in protection. The (DP) cells
are held in place by a capsule that surrounds the (DP) cells
and extends to the sides of the hair follicle to the epidermis.
The structure of the hair follicle sits on a pad of fibrous
tissue called the Arao Perkins body. Nerve fibers and
blood vessels penetrate through small holes/gaps in the hair
capsule base and move into the (DP) area. The proportional size of these holes/gaps are directly related to the overall thickness of your hair. The larger the holes/gaps increases the number of cells, thus increasing the thickness of your hair.
In the organization of a single hair fiber 3 "alpha helices" are twisted together to form a "protofibril" This is the first fibril structure of the hair. Nine protofibrils are then bundled around two or more to form an eleven stranded structure known as "microfibril" These microfibrils are embedded in an unorganized protein matrix of high sulfur content. Hundreds of microfibrils are connected into an irregular fibrous bundle called a " macrofibril" These macrofibrils are grouped together to form the cortex layer of the hair fiber. Packed dead cells surround these structures and are known as the cuticle layers of the hair. In the center of these structures lies the medullary canal.
The cystine bond also known as the disulfide bond, sulfur bond, or just the S bond is formed by crosslinks between the cystine amino acid of the main polypeptide chain. This bond is perpendicular to the axis of the hair and between the polypeptide chains. Cystine is rich with sulfur which plays a crucial role in bond formation. It is produced by the keratinocytes. These cells are located in the bottom of the derma papilla
(DP). Due to its position in the hair, it is responsible for the hair's strength or abrasion resistance. It actually holds hair fibers together. These crosslinks are frequent in the hair fiber, with a maximum of frequency of one cystine bond every four turns of the alpha helix. It is this bond that holds your hair together and gives rise to the hairs overall strength accounting for up to 90% of the strength.
It is essential to break this bond in order to change your hairs appearance. Whether you are adding or removing colour, perming or straightening your hair this bond must be broken. Unfortunately, not replacing this bond will account for your hair feeling dry and damaged.
Bonds associated with Keratin protein.
When hair is in its natural state it is referred to as alpha keratin. The original configuration of this protein structure is held by bonds found in the cortex layers of the hair. As stated earlier, keratin protein begins with an alpha helix building into protofibrils, microfibrils, macrofibrils, then cortex layers. The bonds are located within each and every alpha helix.
The Hydrogen bond : Is an electromagnetic attractive interaction between polar ( charged) molecules, in which hydrogen is bound to a highly electronegative atom, such as nitrogen , or oxygen which is readily available in keratin protein. This bond is located between the coils of the alpha helix and is responsible for the ability of the hair to be stretched and return to its original shape. It gives hair its elasticity. The hydrogen bond is electrolytically controlled and are the most readily broken down and most readily reformed. They are responsible for up to 30% of the strength and up to 50% of its elasticity. Hydrogen bonds are easily broken with the addition of heat. In the case of water ( which accounts for up to 12-15% of your hair and as much as 35% by weight ) becomes steam when heat is applied making this hydrogen bond very weak. Its is essential to reform this bond after using hot tools on your hair. Current products do not address this breakage. All Hair pHix products will replace and enhance this bond.
The Salt bond : Is an ionic bond. Ionic bonds involve electrostatic attraction between oppositely charged ions. These ions represent atoms that have not lost one or more electrons ( know as cations) and atoms that have gained one or more electrons ( known as anions) In hair it is elctrolytically controlled bond formed by the electron transfer from the side chain of a basic amino group ( an amino acid with OOC- group ) to the side chain of an acidic amino acid. This occurs in a position paralleled to the axis line of the rotation of the helix in the hair, It represents a small amount of your hairs strength and elasticity. With an increased pH above 5.5 applied to your hair will instantaneously break the salt bond in your hair. With the addition of keratin amino acids Hair pHix will aid in repairing damage done to this bond.
The Cystine bond : Is probably the most important bond found in human hair, It is this bond that must be broken in order to change the colour structure ( perms, straightening treatments) of your hair. Also known as the disulfide bond, sulfur bond, or just S bond. It is formed by cross-linking between cystine residues (amino acids) of the main polypeptide chains. As discussed earlier the cystine bond accounts for as much as 90% of your hairs overall strength and toughness. However, it is easily broken when a substance of a pH of 5.5 or greater is applied. Since most shampoos professionally available and over the counter have a pH greater than 5.5 - is why hair colour fades, straightening treatments and perms reverse.
Since Hair pHix products all maintain a pH of 4.5-5.5 ( hairs natural pH) ensures no colour loss or treatment reversal will occur while using our products. With infusing all products with cystine amino acids, Hair pHix will help reverse any damaged caused by chemical treatments and colouring.
The Sugar bond : Is formed between the side of the chain of amino acid having an OH (oxygen bonded to a hydrogen) group and an acidic amino group. This bond is also formed perpendicular to the axis of the hair. This bond accounts for little strength and moisture retention.
(IRS) results from matrix cells located above the hair follicle. It can be divided into many layers. A single cell thick (IRS) cuticle layer is located adjacent to the hair fiber. It interdigites with the hair fiber cuticle layer called the Huxley layer may comprise up to four cell layers. Then there is a single layer named the ( IRS) Henley layer. It runs adjacent to the ORS layer
All Hair pHix products are formulated with keratin protein, keratin amino acids, and cystine amino acids, ensures whether environmental, chemical, or heat induced will be repaired or reversed. Hair pHix improves hair strength and vitality by as much as 10 times greater than other conventional professional products available today.
Growth cycle of hair:
There are three phases associated with hair growth.
Anagen, Catagen and Telogen phases
Anagen phase:more commonly known as the growth phase. Approximately 85% of all hair is in the growing phase at any one time. It can last anywhere from 2-6 years. Hair grows approximately 10cm per year.
Catagen phase:more commonly known as the transitional phase. At the end of the Anagen phase the catagen phase last about 1-2 weeks. During this phase the hair follicle shrinks. The lower part is destroyed and the derma papilla breaks away to rest below.
Telogen phase:following the catogen phase the telogen phase last 5-6 weeks. During this time the hair does not grow but stays attached to the follicle while the derma papilla stays in the resting phase. Approximately 10-15% of all hair is in this phase at any one time. At the end of the end of the telogen phase the hair follicle re-enters the anagen phase. the derma papilla and base of the follicle join together again and a new hair begins to form. The new hair pushes the old hair out and the growth cycle starts over again. Cell structure and strength determine overall health during this phase.
Lipids (fats/oils) and moisture (water) found in human keratin.
To keep the bonds in your hair strong you must maintain a healthy hair pH(4.5-5.5) so that they may maintain proper moisture retention. If your hair feels dry it could be due to a myriad of reasons. Using products with a high pH as discussed or just due to not replacing the essential moisturizing ingredients naturally found in your hair. When hair is properly nourished it will be soft smooth and resistant to damage.
Lipids account for 3% of your hairs composition and are produced in the hair bulb. They are formed from sterols, fatty acids, and cerimides.
Sterols: Sterols ( steroid alcohols) are organic molecules that are readily found in plants.
Common sterols found in humans is cholesterol. Plant sterols are called phytosterols. Sterols are important in root hair initiation and growth. Abundant in the plasma membrane of root apex cells. They specifically accumulate in the trichloblast during the prebulging and buldge stages and show polar accumulation in the tip during root hair elongation but are distributed evenly in mature root hair . Root hair formation represents one of the best model systems for studying plant cell polarity, as the axially elongating trichloblast ( root hair-forming epidermal cells) established a new polarity axis prior to root hair formation. In other words, plant stem cells may initiate new hair growth but further studies are required.
Fatty acids: Fatty acids are carboxylic acid with a long "chain" associated with it. Either saturated or unsaturated, most fatty acids come from triglycerides or phospholipids . Omega-3 fatty acids feed your hair within the body. Eating a diet high in omega-3 fatty acids will help the overall health and appearance of your hair. Diets low in these fatty acids may appear with hair loss and thinning hair.
Ceramides: Comes from the Latin word for wax and are a family of waxy lipids (fat/oil). Composed of a sphingosine (18-carbon amino alcohol with an unsaturated hydrocarbon chain) and a fatty acid. It is a class of cell mebrane lipid. Found in high concentrations within the cell membrane. They represent an important component of structural integrity but can participate in a variety of cellular signaling. This includes regulating differentiation , proliferation, and regulating cell death. These three fats are present essentially in the intercellular cement of the cortex and the cuticle and help maintain impermeability and ensure cohesion of the capillary fiber.
The Sebaceous glands: next to the hair follicle, supply the sebum. This mixture of triglycerides, waxes and squalene ( a natural 30-carbon organic compound) found in vegetable oils, of which avocados and coconuts are rich in. They form a film on the hair and skin to lubricate and keep the cuticle supple and soft. Applying oils to the hair without reforming broken bonds may cause hair to become more dry and brittle. Although the hair may feel soft, it is only topical. Hair must be treated from the inside-out. Repair the bonds, lower the pH of your hair, and then add oil if you choose to use them.
Water accounts for 12-15% of your hair and can constitute up to 32% of your hairs composition by weight.
Applying oils without bond reformation can prevent your hair from holding its natural moisture balance thus causing the original hair structure to become dry and brittle. Water plays an integral role in the hair shaft and accounts for softness and strength.
By using Hair pHix products you assure that your hairs bonds, protein, amino acids, water content and lipids are all maintained at a healthy level. Thus it will help the overall health and appearance of your hair even in the most chemically damaged situations. Hair pHix will help eliminate the worries of damaged caused by colouring and chemical straightening.