Hair is made up of a protein called keratin, the same protein that makes up your nails and skin. It grows from follicles, tiny pits in your skin.
The shape of your hair is determined by the shape of your hair follicle.
* Straight hair has round follicles. This allows the hair shaft to grow straight.
* Curly hair has oval-shaped follicles, causing the hair to grow in a spiral or coil.
* Wavy hair falls somewhere in between, with follicles that are a bit rounder than oval-shaped.
But it's not just the follicle!
Other factors also contribute to hair texture:
* Genetics: Your genes determine the shape of your hair follicles.
* Hormones: Hormones like androgens can influence hair texture.
* Chemical treatments: Treatments like perms and relaxers can alter hair shape.
* Environmental factors: Heat, humidity, and even pollution can affect hair texture.
The shape of the hair follicle influences the amount of disulfide bonds in the hair shaft. These bonds, created by the amino acid cysteine, are what give hair its strength and shape.
* Straight hair has more disulfide bonds distributed evenly throughout the hair shaft.
* Curly hair has fewer disulfide bonds, clustered more heavily at certain points. This creates the bends and curves that define curls.
It's a fascinating interplay of genetics, biology, and chemistry that makes our hair unique!