Hair structure

Updated: Oct 15, 2020

A mature strand of human hair is divided into two parts;

The hair root  

The hair root is the part of the hair located below the surface of the epidermis (the outer layer of the skin). It’s like a plant’s root that grows underneath the soil.

The hair shaft

The hair shaft is the portion of the hair that shows the epidermis, (Scalp), like the plant’s stem that grows above the soil.

The five main structure of the hair root including the hair follicle, hair bulb, dermal papilla, arrect pili muscle, and sebaceous (oil) glands.

Hair Follicles

(HAYR FAWL-ih-kul) is a protective tube or pocket that grows around the hair root and protects it.   

 We’ve got hair follicles all over our body except for the palm of the hands and the soles of the feet.  The follicles extend downwards from the epidermis ( the outer layer of skin) to the dermis (the inner layer of skin), where it surrounds the dermal papilla (a small cone shape at the follicle base).  Sometimes a bunch of hair can grow from one single follicle.

Hair bulb

(HAYR BULB) Is the lowest part of the hair strand.  It is the thickened bulb (club) structure that forms the lower part of the root.  The lower part of the hair bulb fits over the dermal papilla and covers it.   

The dermal papilla 

(plural: dermal papillae) is a small, cone-shaped elevation located at the base of the hair follicle that fits into the hair bulb.  The dermal papilla contains the nerves and the blood.  Some people refer to the dermal papilla as the mother of the hair because it provides the nutrients needed for the hair growth.

The arrector pili 

The arrector pili muscle is a small involuntary muscle in the base of the hair follicle. Intense emotions of cold sensations cause it to contract, which makes the hair stand straight up and results in what we call goosebumps.

The Sebaceous glands 

The sebaceous glands are the oil glands in the skin that are connected to the hair follicles.  The sebaceous glands secrete a fatty or oily substance called sebum.  Sebum lubricates the scalp.  It’s our natural oils, and it’s essential to the skin and hair.