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Structure of Scalp and Hair

The scalp is comprised of three layers: epidermis (uppermost), dermis (middle) and subcutaneous tissue (bottom) layer. 

  • Epidermis – comprised of approximately fifty cells thick and is the layer with the most interaction from daily styling or hair manipulation.
  • Dermis – Comprised of collagen proteins that yields support and strength to the skin.
  • Subcutaneous tissue – Comprised of the scalps’ blood vessels and fatty tissue.


A critical element in any healthy hair-growing tactic is to understand the importance of the scalp.  The scalp is the initial formation of hair, and if proper care is administered, it will produce healthy hair.  To grow healthy hair a few fundamental topics should be understood. 

  • Your scalp should remain clean, in healthy condition, flexible and positively stimulated (daily 5 minute gentle scalp massages are great).
  • Massaging your scalp gently can increase nourishing blood circulation to better supply nutrients to the hair follicles.  

The follicle (root) is the starting point of every new hair. A combination of oxygen, glucose and healthy nutrients are key requirements to produce healthy hair growth at the base of the follicle to push upward to create a healthy hair shaft.  Many healthy hair shafts will create a full head of healthy hair. ***Taking into consideration that there’s no medical health issues****

Hair Shaft

To try to alleviate any frustrations you may encounter, I will highly suggest refraining from solely focusing on finding the right product to yield the ideal look and learn basic hair anatomy. Learning the basics of hair structure will provide a guide as to why some products and techniques work and why others fail.  Knowledge is power and I will share information that will allow you to make wise and conscientious decisions concerning the health and longevity of your Rockin’ Natural Hair.  

The hair shaft is comprised with three layers: medulla, cortex and cuticle.

  • Medulla (Internal Structure) – the innermost layer of the hair shaft and generally only found in thick, coarse hair. Dale H. Johnson, Hair and Hair Care (New York: Marcel Dekker, 1997). Jutta Maria Quadflieg, “Fundamental Properties of Afro-American Hair as Related to Their Straitening/Relaxing Behavior,” 2003. Individuals with thin, fine hair strands generally lack the innermost layer in their hair shaft.
  • Cortex (Internal Structure) – If the medulla is non-existent in the hair shaft, the cortex is the innermost layer of the hair shaft and it accounts for the greatest percentage of the hair fiber.  John Halal, Hair Structure and Chemistry Simplified, 4th ed. (Milady, 2002).  Hair strength and elasticity originates from the cortex.  The cortex’s is made up of several long chains of proteins that coil and twists around each other to create a formation of the hair fiber’s basic structure. 
  • Cuticle (External Structure) – Numerous fatty acids and proteins creates the outer most layer of the hair shaft. The cortex is protected from environmental (wind, sun, etc.) and physical (combing, brushing, washing etc.) elements by a protective cuticle layer. Claude Bouillon and John Wilkinson, The Science of Hair Care (Boca Raton, Fl.: Taylor & Francis, 2005.) Dale H. Johnson, Hair and Hair Care (New York: Marcel Dekker, 1997).



Natural Hair

Definition:  Black Hair that is in its natural state (hair that is not altered by chemical straightening products).

Myth – Natural hair is not fragile. False.  Natural hair is very fragile due to the many combinations of angles, curls, twists, kinks and bends in hair strands.

  • Hair in its natural state usually doesn’t follow a perfect uniformed pattern. There are various angles, curls, twists, kinks and bends in hair strands.  
  • To reach optimal lengths, individuals who wear their hair natural must realize natural hair is prone to tangling and knots with the combination of various angles, curls, twists, kinks and bends on each hair shaft makes natural hair prone to manipulation and breakage if not handled with care and patience.
  • Healthy natural hair is elastic (when stretched all hair doesn’t snap off and break, instead it will return back with little or no breakage due to manipulation).
  •  Applying water and a moisturizing product prior to stretching or manipulating natural hair decreases the chances of hair breakage.


  • Growing phase (anagen) – Hair is continuing to grow
  • Resting phase (catagen)  – Hair takes a growth break
  • Shedding phase (telogen) – Hair naturally sheds
  • Optional hair phase (exogen) – Follicles rest (can last five to seven months); as we get older, the phase can last longer. Then the hair cycles back to the growing phase. These phases are never ending. Taking into consideration that there are no health or other issues causing adverse effects on hair growth. 



PH is short for potenz hydrogen, Danish translation “hydrogen strength”.  PH is a measurement of ions in water-based mixtures.  Extremely high or low PH severely affects the structure inside the cortex of your hair.

Example:   Relaxers have an approximate PH of 11, enabling your cuticles to lift and change the natural fibers into permanently straight strands, ultimately hair begins to soften and lose strength.

PH ranges from 0 – 14, PH readings from 0-6.9 are considered acidic. Products and mixtures that contain a PH from 0-6.9 allow the hair shaft cuticle layer to close, which allows the cortex of the hair to be protected.

PH ranges from 7.1 – 14 are considered basic or alkaline. Products and mixtures that contain a PH from 7.1-14 allow the hair shaft cuticle to open which allows the hair to become weaker and more susceptible to damage.

Pure water has a neutral PH of 7. 

Some hair products reveal its PH level, however using litmus paper that you can purchase from a drug store can help determine the PH level on any water-bases substances.


Compare your hair to a frayed thread from a sewing thread spool.  The thickness of frayed thread is comparable to a medium-sized strand of human hair.  If you hair strand is larger than the frayed thread, your hair is thick.  If you hair strand is smaller than the frayed thread, your hair is fine.


Density is the thickness of the hair; density can be adversely affected by stress, health problems or hormonal changes.  A good way to determine density is to gather your hair into a ponytail, place your forefinger and thumb around the base of the ponytail (close to your scalp), if the width is larger than a quarter, you have thick hair.  If the ponytail width (close to your scalp) is smaller than a quarter but larger than a nickel, your hair is normal.  If you ponytail width (close to your scalp) is smaller than a nickel, your hair is fine.


Hair’s ability or inability to absorb water into the cortex is hair porosity. Low porosity or poor porosity hair doesn’t easily absorb water.  Good porosity hair holds onto moisture nicely.

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