Hair follicle anatomy

Understanding the hair follicle anatomy is essential to understand essential treatments such as laser hair removal, PRP hair loss treatments, hair restoration and hair transplantation. Moreover, it helps us to understand the pathogenesis of acne and its treatments.

The hair follicle structure

The hair follicle is a small sac-like structure containing the hair’s root. The sebaceous gland is also located within the hair follicle and produces an oily substance called sebum. Sebum helps to lubricate the hair shaft and keep the scalp hydrated. The hair follicle also contains a small muscle called the arrector pili. This muscle helps keep the hair erect, making it possible for animals to ‘fluff up’ their fur to appear larger. The hair follicle is connected to the nerve endings in the skin, which is why we feel pain when our hair is pulled. The depth of the hair follicle varies depending on where it is located on the body, but it typically extends down into the dermis or subcutaneous layer of skin.

Location within the skin

hair follicles are located in the dermis and house the cells that produce hair. The hair follicle is surrounded by a layer of connective tissue called the epithelium. The epithelium is composed of two types of cells: keratinocytes and melanocytes. Keratinocytes are responsible for producing keratin, the hair’s main structural protein. Melanocytes produce melanin, which gives hair its colour. The hair follicle also contains blood vessels that supply nutrients to the cells that produce hair. When these cells are healthy, they can continue to produce new hairs throughout a person’s lifetime. However, when the cells become damaged or diseased, they may stop producing new hairs, resulting in hair loss.

Hair follicle composition

The wall of the hair follicle is composed of three layers: an outer layer of epithelial cells, a middle layer of connective tissue, and an inner layer of muscle fibres. The epithelial cells are responsible for keratin production, giving the hair strength and flexibility. The connective tissue supports the hair follicle, and the muscle fibres help anchor the follicle in place. Together, these three layers keep the hair follicle healthy and functioning properly.

Sebaceous glands

The sebaceous glands are tiny glands located at the base of each hair follicle. These glands secrete sebum, an oily substance that lubricates and protects the hair. Sebum helps to keep the hair healthy and prevents it from becoming brittle and breaking. It also helps to repel dirt and debris, keeping the scalp clean. The sebaceous glands produce the natural oils that give the hair its lustrous shine. Without these glands, the hair would quickly become dry and dull. In people with oily skin, the sebaceous glands produce too much sebum, leading to excess shine and buildup on the scalp. If not properly controlled, this can eventually lead to acne. While people with dry skin may not have to worry about excessive oil production, they may still suffer from dryness and flaking due to a lack of sebum. Fortunately, many products can help replenish the scalp’s natural oils and keep the hair looking healthy and radiant.

Hair grows from within the hair follicle 

it starts as a small bud called a germinative center and then grows outward. The answer lies within the hair follicle if you’ve ever wondered how hair grows. The hair follicle is a small, cup-shaped indentation in the skin that houses the root of the hair. The hair follicle also contains the cells that produce new hair growth. These cells are called germinative cells, and they divide and grow to form a small bud called a germinative center. The new hair shaft grows outward from here, eventually pushing the old hair out of the follicle. The entire process takes place beneath the skin’s surface, which is why you can’t see new hairs growing until they reach a certain length. So next time you’re admiring your luscious locks, remember that it all starts with a tiny germinative center deep within your hair follicles.

The hair follicle growth phases

There are three phases of hair follicle growth: anagen, catagen, and telogen. The anagen phase is the active growth phase, during which the cells in the follicle divide rapidly. This phase lasts for several years and is responsible for most hair growth. The catagen phase is a transitional period lasting for a few weeks, during which the follicle shrinks and the cells begin to Dak Lak slowly. The telogen phase is the resting phase, during which the cells in the follicle are inactive. This phase lasts for several months before the follicle begins growing again. Each hair follicle goes through these three phases multiple times throughout a person’s life.


About the Author

Kamal Alhallak, Ph.D. in Pharmacy, MBA

Dr. Alhallak has established himself as a leading figure in the field of cosmetics and aesthetics, notably in the Canadian healthcare industry. In 2016, he established the Albany Cosmetic and Laser Center, which offers patients cutting-edge procedures such as laser skin resurfacing, IPL photofacials, neurotoxic and dermal fillers, and more. Because of its mix of cutting-edge technology and individualised attention from Dr. Alhallak, the facility has become one of Alberta's most popular places for aesthetic care and laser research. Dr. Alhallak was designated one of the Top 100 Healthcare Leaders by the International Forum for Advancement in Healthcare (IFAH) in 2021.

You can pre-order the “The Ultimate Guide for Laser and Ipl in the Aesthetic Field” now. This Book is authored by the health professional team including: Dr. Kamal Alhallak, Dr. Salem Tomi, Dr. Adel Abdulhafid, R.N. Dima Omran

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