What is the Difference Between Hair Follicle and Hair Root

The main difference between hair follicle and hair root is that a hair follicle is a tube-like structure that surrounds the root and strand of hair, whereas a hair root is a structure that extends deep into the dermis at the hair bulb.

Hair follicles and hair roots are two structures of the hair that occur near the skin. Their function is to attach the hair to the skin.

Key Areas Covered

1. What is Hair Follicle
     – Definition, Structure, Function
2. What is Hair Root
    – Definition, Structure, Function
3. Similarities Between Hair Follicle and Hair Root
     – Outline of Common Features
4. Difference Between Hair Follicle and Hair Root
     – Comparison of Key Differences

Key Terms

Hair Follicle, Hair Root

What is Hair Follicle

The hair follicle is an organ that occurs in the skin of mammals. Generally, it occurs in the dermal layer of the skin. Also, there are around 20 types of cells in the hair follicle. And, each cell has a distinct function. The main function of hair follicles is to regulate hair growth through the action of hormones, neuropeptides, and immune cells. Due to the presence of different types of cells, hair follicles can produce different types of hair at different parts of the body. For instance, terminal hair grows on the scalp while lanugo hair covers the body of the fetus in the uterus.

Figure 1: Hair Structure

Furthermore, hair follicles are responsible for the growth of hair. This growth generally occurs in distinct sequential stages. Anagen is the first stage of hair growth, and it is the active growth stage of hair. The second stage is a resting stage called elogen. Thirdly, a catagen stage occurs in which the regression of hair follicles occurs. Then, there is a stage of active hair shedding occurs called exogen. The final stage of hair growth is kenogen; here, empty hair follicles and the growth of new hair occurs. Moreover, humans have the longest period of hair growth among all other mammals.  

What is Hair Root

Hair roots are hairs that occur below the surface of the skin, anchoring to the follicle. Hair roots end deep in the dermis at the hair bulb. They have a mitotically active layer of cells called a hair matrix. In addition, the hair papilla is the structure that surrounds the hair bulb. Generally, hair is a keratinous structure that grows out of the epidermis. Hair is made up of dead, keratinized cells.

Figure 2: Hair

Moreover, the main function of hair roots is to contract the hair in response to the nerve impulses of the sympathetic nervous system. In general, the other parts of the hair include the hair shaft, hair bulb, hair matrix, and hair papilla.

Similarities Between Hair Follicle and Hair Root

• Hair follicles and hair roots are two types of structures that occur at the end of the hair.
• Their function is to attach the hair strand to the skin.

Difference Between Hair Follicle and Hair Root

Definition

A hair follicle refers to a tube-like structure (pore) that surrounds the root and strand of a hair, while a hair root refers to a structure that occurs in the skin and extends down to the deeper layers of the skin.

Significance

A hair follicle begins at the surface of the dermis, while a hair root occurs in the deep of the dermis at the hair bulb.

Function

The main function of hair follicles is to grow hair, while the main function of hair roots is to contract the hair in response to nerve signals from the sympathetic nervous system.

Conclusion                                                                                               

In brief, hair follicles and hair roots are two structures of the hair. Both occur near the skin. Therefore, they attach the hair to the skin. A hair follicle is a tube-like structure that surrounds the root of the hair strand. It begins at the surface of the dermis and its main function is to grow hair. A hair root, on the other hand, is a structure that occurs in the skin and extends down to deeper layers of the skin. Generally, hair roots occur in the deep of the dermis at the hair bulb. The main function of hair roots is to contract the hair in response to nerve signals. Therefore, the main difference between hair follicle and hair root is their occurrence.                               

References:

1. Learning, Lumen. “Biology for Majors II.” Lumen, 

Image Courtesy:

1. “Blausen 0438 HairFollicleAnatomy 02” By BruceBlaus – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “ArmHair” By Zephyris – Own Work (CC BY-SA 3.0) via Commons Wikimedia