The cuticle is really the equivalent of the roof on a building. The only thing preventing water from above from soaking through the wood/stone and brick of your house is the roof. The roof also keeps in heat and blocks out cold. This is the same way that the cuticle works. It blocks moisture from leaving the hair shaft. It also slows down entry of substances (water/oils/conditioning agents) and it protects the shaft from damage (many times when strength testing, the cuticle will rupture before the shaft does - therefore the cuticle is protecting the shaft by taking the force first). So now that the structure of hair is known, it is time to answer the big question, Can you nourish hair? Does hair require nourishing given that it is technically dead, is this really possible?
Tune in tomorrow for Part 2 of 3 : Can you nourish hair? References for the hair structure information above Chemical and Physical Behaviour of Hair – Clarence Robbins Forensic Examination of Hair – James Robertson