Tuesday, September 27, 2011

Hair Theory: Hair Structure


I wanted to come at you first and foremost with some information about the structure of the hair strand and some of the challenges we curly girls face because of the structure of our strands.

Ok, so the  basic layers of a hair strand are captured in the image below. Any type of hair from pin straight to tightly curly  is made up of these three layers. This is just a basic overview of each layer for general knowledge, not going into too much detail to confuse anyone.
Cuticle- This is the outermost layer. It is made up of  transparent/colorless scales that overlap eachother in order to protect the inner layers of the strand. Most topical hair products are aimed toward affecting the cuticle in some manner.

Cortex-This is the largest layer of the strand and is made up of a protein called keratin and pigment. Within the cortex there are protein bonds, the number of bonds determine the texture and strength of the hair. Greater the number of bonds, the curlier the hair. The pigment present in this layer also determines hair colour. All chemical services/thermal services aimed towards changing the curl pattern of the hair or changing the colour of the hair affects the cortex.

Medulla-This is the innermost layer and its actual purpose uncertain.

Challenges for curly girls:

1. Curly hair is often dry as it is difficult for the natural sebum (oil) produced by the scalp to move downward towards to end of the strand. This is why most curly girls add oil in their hair daily while persons with naturally straight hair complain about having 'oily/greasy' hair.

2. The cuticle layer of curly hair opens easily just due to the curl pattern. An open cuticle is one of the main reason we experience breakage an splits as the strand is not properly protected. Relaxers and/or chemical services done by most african women also raise the cuticle causing the cortex to be open to the elements. In my up coming articles about healthy hair practices you will hear me talk about ways that we can close this cuticle layer and thus greatly minimise damage.

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