Hair Loss Basics

July 10, 2024

Anatomy of Hair Follicle

Humans have approximately 5 million hair follicles and 100,000 of them are located on the scalp. In humans the whole body is covered with hairs except palm, sole, lips & genitals. Hair serves the aesthetic function of adding beauty to the human body & it’s a characteristic feature to the mammals.

Hair transplants have become increasingly common as they are a permanent solution to baldness. Patients undergoing hair transplants must know about their hair anatomy and how it affects hair growth. Extreme hair loss can severely affect your self-esteem and overall well-being. Thanks to advanced hair transplant procedures, you can sport denser hair.

Having a thorough understanding of the growth cycle after a hair transplant is crucial. It will help you manage your expectations properly. At MedLinks, we always strive to offer our patients detailed information to make them feel empowered. Here are the essential aspects to learn about the anatomy of your hair and its growth after a transplant.

Hair is a derived of the epidermis and consists of two different parts:

  • Hair follicle: living part located under the skin.
  • Hair shaft: non-living part above the skin.

A muscle called arrector pili is found between the hair bulge area & dermoepidermal junction. Above the insertion of this muscle sebaceous gland & in a few specific regions apocrine glands open in the hair follicle.

Hair follicle:

It is a very important growth structure of the hair consisting of two main parts.

  • Upper infundibulum & isthmus: from insertion of arrector pili muscle to the skin surface.
  • Lower suprabulbar & bulb: begins from the base of the hair follicle and ends at the insertion point of the arrector pili muscle

Infundibulum uppermost part of the hair follicle extending from the skin surface to the opening of sebaceous gland into the hair follicle. It is usually filled by the sebum secreted by the sebaceous gland.

Isthmus is the upper part of the hair follicle between sebaceous glands opening to the insertion arrector pili muscle. Here epithelium keratinization begins with the lack of granular layer named “trichilemmal keratinization”.

The suprabulbar region of the follicle, below the isthmus and above the hair bulb, is comprised of three layers from outermost to innermost: outer root sheath, inner root sheath and hair shaft

Hair bulb: it is the expanded onion shaped portion of the lower part of the hair follicle. It is the active reproductive means living portion of the hair follicle.bulb is connected to the papilla from below which is surrounded by matrix cells and pigment cells. Hair shaft develops from the matrix cells.

Nerve supply: Nerves related to the hair follicle are similar to the dermal nerve network including sensory afferents and autonomic sympathetic nerves. These nerve fibres form a circular layer around the bulge area of terminal follicles and the bulb area of vellus follicles. Several types of nerve endings are associated with hair follicles like Free nerve endings transmit pain, lanceolate nerve endings detect acceleration, Merkel cells responsible for pressure sensation and paolo-Ruffini corpuscles detect tension.

Vascular supply: Cutaneous vascularization is provided by arterioles, which are concentrated at the lower portion of the hair follicle and compose vascular network. During the hair cycle some alteration in the perifollicular vascularisation occurs due to up & down regulation of vascular endothelial growth factor expression.

Hair Shaft:

It’s basically a thin strand of hardened cells that is visible above the scalp. The thickness of a hair varies something in-between 0.04-0.12mm. Hair shaft is consisted of three layers:

  • Cuticle
  • cortex
  • medulla

Cuticle: It’s the most outer layer of the hair and protects the inner layers from harm from the external physical & chemical insults. It has a tough and dense structure. It’s colorless in nature and allows light to shine through it. Around 10% of the hair diameter consists of the cuticle layer. It’s known to provide shine and elasticity to the hair. Cuticle cells are flat & square shapped which are adhered tightly to the cortex cells.

Cortex: It’s the thickest layer of the hair and constitutes around 80-90% of the hair’s diameter. It contains numerous hardened fibrous cells which are made up of various protein molecules. These cells are arranged together in bundles surrounded by keratins. These cells coalesce tightly and are placed parallel to the axis of the shaft. It’s also known to contain the pigment, Melanin giving the hair its natural colour.

Medulla: It is located in the center of the hair shaft preferably presented in coarser fibers. . Its thickness ranges according to the thickness of the hair. Medulla’s presence in a hair determines its stiffness and thickness. It’s not at all present in fine hairs.

The Composition of Hair – Things to Know

The newly implanted follicles contribute to your hair growth. It lies at the intersection of the hypodermis and the dermis and is commonly known as the bulb. The hair shaft supplies blood to your scalp. It provides your hair with vital nutrients and ensures that they remain healthy. This small vessel also supplies your hair with essential minerals, amino acids, and vitamins.

Your hair is also surrounded by sebaceous glands responsible for secreting sebum. It is the hair’s natural lubricant. The scalp has delicate pores on its surface which ensures the proper drainage of sweat. Your hair growth cycle after a transplant at our clinic greatly depends on your ability to stick to post-operative instructions.

Essential Aspects to Learn About Hair’s Structure

Human hair contains keratin. It is a fibrous and helical protein that forms an integral part of your skin. Your hair comprises eighteen amino acids like proline, arginine, threonine, etc. The structure of your hair contains the following three parts.

  • The Pith

The pith, also known as the medulla, is the shaft’s central part. The main composition of the pith is an amorphous and greasy substance.

  • The Cuticle

It is the thin outer layer of your hair that protects it from external elements. The cuticle is integral to the overall nourishment of your hair follicles.

  • The Cortex

The cortex renders your hair with the flexibility and elasticity it requires. The cells in the cortex are associated with lipids and proteins.

Hair Growth Cycle After a Transplant

Besides knowing hair anatomy, you should also know about the growth cycle of your hair after a transplant. The growth cycle of your hair comprises of four different phases. Anagen, catagen, and telogen are the primary three phases that cover the growth of your hair.

The exogen phase refers to the shedding phase where old hair sheds. Each phase has its own distinctive timeline and is commonly affected by age, nutrition, and overall health. Listed are the stages of hair growth to know after undergoing a hair transplant at MedLinks.

Anagen – The Hair Growth Phase

Your hair growth after a transplant at our clinic commences with the anagen phase. It is also known as the most extended phase. During this phase, your newly transplanted hair follicles will push out hairs. These hairs will continue to grow. At any point in time, around 90% of your hair is in the anagen phase.

Catagen – The Transition Phase

The catagen phase lasts for ten days. During this phase, the hair follicles shrink and there is a gradual decrease in the rate of the hair growth. Only 5% of your hairs are in the catagen phase after a hair transplant at our centre.

Telogen – The Resting Phase

Around 10% to 15% of your hair is in this phase after a hair transplant. In this phase, you won’t notice any gradual growth of hair. It is essential to take good care of your hair and follow the post-operative instructions during this phase.

Exogen – The Hair Shedding Stage

We usually term the exogen phase as the extension of the telogen stage. The exogen phase is characterised by the shedding of hair from the scalp. It is normal to lose 60 to 100 hair strands during this stage after surgery. The exogen stage is followed by intense hair growth and you notice the visible changes.

Hair Colour after a Transplant – Key Things to Know

We usually suggest our patients to wait for four weeks before colouring their hair after a transplant. Usually, hair dyes contain harsh chemicals that can be harmful to transplanted grafts. Colouring your hair soon after a transplant may cause irreversible damage to your scalp.

After a hair transplant surgery, it is crucial to follow the right aftercare and recovery guidelines. It includes adhering to the timeline of colouring your hair at the right time. Our Perfect i hair transplant is redefining hair restoration in India.

It is an advanced procedure to execute a FUE hair transplant. The instant implantation of the extracted follicles makes this procedure highly effective. We also don’t use implanters while performing the Perfect i hair transplant. Contact us today to learn more about our hair transplant procedures.

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Disclaimer:The content published on this website( is meant to spread awareness and educate the concerned patients regarding baldness and hair transplants as well as the treatment options available for baldness and hair transplant treatment in Delhi India. Any information on the website shall not be regarded as a prescription from a professional dermatologist. We recommend visiting a dermatologist in person for the right diagnosis and the treatment for any hair issues. We do not guarantee specific results as the treatments and the results vary from person to person.

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