Hair Science

 

What is the Hair made of? and some knowlegde about it. It will help you to understand your hair better...

 

Keratin, the building material for hair, belongs to the largest group of proteins (also known as polypeptides).

The smallest components of polypeptides are the various amino acids. The following consist mainly of polypeptides: Skin, Cartilage, Feathers, Nails, Claws, Silk

One group of polypeptides are the "fibrous proteins". Examples of these are "Collagen" and "Kreatin". To date, approximately 24 amino acids have been identified in the composition of proteins.

In the composition of hair, the proportional content of individual amino acids in the "helix" (fibre) is very different to that in the "matrix" (filler).

Amino acids combine with proteins in a unique way, forming chains. The amino acids are inter-connected by short links (amide link) with the rest of their structure projected to the side.

For example (R) is one of the 17 different residual amino acids.

The illustration is a schematic diagram of the crosslinks forming the residual structures: Salt link, Hydrogen link, Sulphur link. These cross-links determine the spatial structure of the polypeptide chains.

 

The alpha helix, a polypeptide chain, is wound in a spiral. It has been shown that this alpha helix is wound in a righthanded spiral.

Several of these helical spirals are wound as a "Proto-fibril". The cross links (see the previous illustration) operate within the helix, but more especially between the chains and the "Matrix" (filler substance).

The filler substance itself also has strong cross links.These links and chemical influences are of crucial importance in the permanent wave process.

The Proto-fibrils are connected to a single multi-strand cable known as the "Micro-fibril".
Hundreds of Micro-Fibrils form an irregular bundle of fibres, the "Macro-fibril". The "cable strand" (fibre strand) is made up of many macro-fibrils. The "hair shaft" in turn is made up of these cable strands.
The "medullar channel" containing the "medulla" is located at the centre of the hair shaft. Its structure has not been fully identified as yet. What is known is that the medullar channel is partially filled with a spongy hornlike substance displaying sizeable cavities in places. The space in between the fibrils (cable strands) and the scale layer (cuticula) is filled with "matrix" (filler substance). This filler substance consists of proteins, not in the form of helical spirals in this case, but in the form of amorphous (shapeless) substance.

The hair shaft is surrounded by the "cuticula" (scale layer). This consists of numerous scale layers (up to 10), positioned on top of each other with their edges always pointing towards the end of the hair. Filler substance is located even between the scale layers, holding the individual scale layers together. The proportion of filler material has been enlarged in the diagram.

We split a hair open in order to examine its internal structure.

Examining the hair by cutting a cross-section is prevented by the filler substance (matrix). Its characteristic plasticity is not altered even at temperatures of - 273 °C.

The action of cutting a cross section produces a spreading effect, blurring the fine definition of the internal structure of the hair.

Magnification x 20.000 clearly shows the coarse composition of the hair structure.

Together, the cable strand bundles from the fibrous core. This is surrounded by several layers of scale.

The hair is held together by means of the filler substance, which determines the elasticity of the hair.

 

A longitudinal section through the hair shows the medullar channel. The medullar channel is not present in each hair or is even sometimes only partially present.

In terms of cosmetics and treatments for hair, the medullar channel is of no significance.

 

Hair Color Science

 

An individual's natural hair color is related to the quantity, size, type, and distribution of cellular bodies called melanosomes, which contain the pigment melanin. There are two types of melanin -- eumelanin and pheomelanin -- which are found in various ratios in each individual hair strand. Eumelanin are oval shaped dark granules that range in color from brown to black and are insoluble in solvents, resistant to chemical treatment and have a complicated chemical structure. Darker levels of hair have a higher concentration of eumelanin. Pheomelanin are diffused small particles that range in color from red to yellow. Its shape is different than eumelanin and it is more soluble. Pheomelanin usually occurs in lighter shades of hair, making light hair easier to lighten. Gray, white or non-pigmented hair is considered by many to be the same although there are subtle differences: Gray hair is a gradual loss of pigment in the hair resulting from a decrease in melanin production. The hair appears to have an absence of pigment, but it is not completely devoid of melanin. In white hair, melanin may be completely absent or dormant.