Hair ( Crowning Glory ) / Function & Disorders

Hair ( Crowing Glory ) Function & Disorders

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For all people, apart from gender, one of the factors of appearance beauty is having thick and beautiful hair. In addition to the beauty that hair on the head brings to people, the hair in different parts of the body has a duty and helps to protect the body. For example, besides beauty, hair on the head protects the scalp from sunlight. Do not damage the skin.

The hairs in the ears and nose prevent the entrance of germs and bacteria in the body, and eyelashes and eyebrows save the eyes from dust and sweat. Even the extra hairs in different body parts effectively maintain and control the body temperature. In this article about the structure and components of hair, stay with us for more information.

hair structure

There are about 5 million hair follicles on the human body, and there are about 100,000 hairs on the head. Each strand of hair contains two parts: the follicle and the stem. The follicle consists of papillae and bulbs that connect the hair to the scalp. 

The shape of the follicle indicates the type of hair, such as straight, curly, curly, etc. The hair bulb is the living part of the hair, which is located about four millimeters below the scalp, that is, the dermis layer of the skin.

The hair bulb is constantly in contact with the blood vessels, and during the contact, it absorbs nutrients for the hair and makes hair cells. when new cells replace the old cells, the old cells move to the surface of the skin. They drive, and these driven cells become hair with the changes they find.

The building material of hair is called keratin, which is obtained from the decomposition of coal, hydrogen, oxygen, sulfur, and nitrogen. On average, an adult human has about 100,000 hairs.

In the following, we will introduce each of the different parts of the hair stem and root:

  • Hair root components

    The hair root consists of 4 parts:

    1. Dermal papilla
    2. Matrix
    3. Root cover
    4. Fat gland


    • Cutaneous papilla

      It is located in the central part of the hair bulb, which works to supply blood to the hair follicle. It has a great effect on hair growth and is also known as the hair core.


    • Matrix

      In this part, keratinocytes (main hair cells) multiply and are filled with keratin. Also, the production of melanocytes (pigments) is done in this part.


    • Root cover

      During hair growth, its job is to maintain and guide the shape of the hair shaft.


    • Sebaceous gland

      It is located next to the hair follicle and helps to keep the hair healthy, soft, and shiny by secreting fat.


  • Components of the hair shaft

    The hair shaft consists of 3 parts:

    1. Medulla
    2. Cortex
    3. Cuticle


    • Medulla

      It consists of oligomeric cells without a nucleus and is located in the center of the stem.


    • Cortex

      80 to 90% of the hair’s weight is represented by the cortex, and it consists of keratin. Even in the cortex, there is melanin (pigment) that gives color to the hair.


    • Cuticle

      It is the outermost layer of hair and protects the cortex. Its job is to resist external factors such as soil, sun, wind, etc., and taking care of this layer is necessary to maintain hair health.

Hair cycle

The more hair, the bigger the brain: Did you know that body hair is tied to intelligence? Well, at least one research study says so. Dr. Aikarakudy Alias has been studying body hair and intelligence for over 22 years and has found that men with more chest hair often hold more important jobs or perform better in school than men with less chest hair. 

So, if you have a rug on your chest, chances are you’re a genius. But you should know that this hair, which has many secrets hidden in it, has a cycle.

The cycle of the hair follicle (the living part of the hair) consists of three stages:

  • Anagen (growth stage):

    The anagen phase is the proliferative phase and occurs when the hair follicle forms a new hair sheath. The length of this step can vary. For hair on the scalp, the growth phase can take 2 to 6 years, while for eyebrows and eyelashes, it may take a few months for the hair to grow. This is the only stage where the lower part of the hair follicle is present.

To detect the beginning of the anagen phase, the dermal papilla sends a message to the stem cells. When the stem cells are stimulated, the lower part of the hair follicle can grow downwards, and a bulb is formed around the dermal papilla. 

Now, the dermal papilla can connect to the matrix cells inside the bulb. Signal for proliferation, differentiation, and upward growth to form a new hair.

  • Catagen stage (stopping hair growth stage):

    The catagen phase is known as the transition or regression phase. It is also the shortest of the three stages, lasting only a few weeks. At this stage, cell division in the matrix stops, and the lower part of the hair follicle begins to regress. 

finally, the lower part of the follicle is no longer there, and the dermal papilla moves upward to connect to the ridge once again. During this process, a mole The hair is formed with a white and hard at the end.

  • Telogen stage (resting stage):

    Hair moles, which are mostly dead, are preserved. In the scalp, these moles are usually kept for about 100 days. Eventually, these hairs are released and shed to start the anagen phase again with new hairs.

At birth, all hair begins in mid-anagen. The human scalp contains more than 100,000 hairs. At any point in time, most hairs are usually found in the anagen phase. 

These hairs can grow about 1 cm per month. However, hair loss is continuous, and people lose about 100 hairs a day on average. Shampooing can double the number of hair loss.

What are the ingredients of hair?

Almost the entire surface of the body is covered with hair except for a few areas, such as the palms of the hands, the soles of the feet, and the mucous areas of the lips and external genitalia. Most of these are fine and colorless hairs. 

Hairs that are located in multiple areas, such as the scalp, eyelashes, and eyebrows, are longer, thicker, and pigmented and are known as terminal hairs. Humans have about 5 million hair follicles, and 100,000 of them are on the scalp.

In this section, we will examine the main materials that make up the structure of hair. These substances are very important and play a key role in hair health and beauty. Knowing these ingredients is essential to having healthy and strong hair.

  • Keratin: the main pillar of hair

    Keratin is one of the main ingredients that make up the main structure of hair. This protein creates structure and strength in hair.

  • Pigments: hair color

    Pigments are also one of the important ingredients in hair structure. These substances give color to the hair and can make them look different. The higher the amount of pigment in the hair, the richer and more attractive the hair color will be.

  • Natural oils: softness and softness of hair

    Natural oils also help to build hair. These oils nourish the hair and make them soft and smooth.

Types of hair

There are different types of hair that can be mentioned below.

  • Greasy hair

    A dry or oily scalp depends on the amount of oil secreted by the hair’s sebaceous glands. This fat lubricates the strands and sheath of the hair, protects it from dryness to some extent, and makes the hair shiny. 

Hair oil softens the hair and makes it easy to comb and style the hair. If these glands are overactive, sebum secretion increases, and as a result, the hair becomes too greasy, which is called seborrhea. The presence of seborrhea causes problems for both scalp and hair. 

In this case, hair roots are suffocated due to the accumulation of fat in the follicles, and as a result, hair loss increases.

    • What is the cause of oily hair?

      Various factors, including heredity, excessive secretion of male hormones (androgenic), nutrition, nervous pressures, and discomforts such as obesity, constipation, and saturation of the liver and gall bladder, are involved in making hair greasy.

In terms of food, people with oily hair need a lot of B vitamins and iodine, and it is better to use more foods that contain these two substances in their daily diet. 

Fish, liver, and egg yolk contain these substances. To treat oily hair, the most important thing is to eliminate oil and fatty foods. If the fat in the hair is due to thyroid gland dysfunction, discomfort, and nervous pressure, you should definitely see a doctor.

  • Dry hair

    Basically, dry hair breaks easily and lacks shine. If you feel that your hair is not alive and shiny and does not have the necessary softness and flexibility, you should change your food plan to some extent and prepare a new plan that contains more vitamin B so that your hair is alive and shines more.

To wash dry hair, you should use an herbal shampoo, reduce the number of times you shampoo, and use warm, not hot, water. After shampooing the hair, use an egg yolk to strengthen the head or add the egg yolk to the shampoo you wash your head with so that the yolk is mixed with the shampoo and does not remain on it. 

In addition to strengthening the hair, natural oils are effective in improving the condition of dry hair.

    • How curly the hair is

      The amount of curly hair depends on the shape of its cross-section. The more oval this section is, the more curly the hair is, and the rounder it is, the straighter the hair is. For example, those who have curly hair are because of the wide and stripy section of their hair.

  • Normal hair

  • mixed hair

Hair disorders

Hair is one of the most glamorous identifiers of beauty in every person. Having healthy and transparent hair can give a hundredfold effect to your charm. But why does the condition of the hair and its clarity not suit us sometimes, or does the hair even start to fall out? 

In such cases, we should know that there is a problem with hair health, which may be caused by a nervous shock or suffering from various scalp diseases.

In general, hair is a fragile and vulnerable tissue, and if we do not treat it very soon when hair diseases occur, the damage may not be cured.

Therefore, it is necessary to know common hair diseases, what to do when faced with such cases, and when to see a doctor. We must know all the things to maintain hair health and prevent hair diseases, not be exposed to stress and nervous shocks, and have healthy nutrition in order to have healthy hair.

Disorders related to hair are either caused by the hair itself and disorders in its different parts or are related to the scalp. In cases related to the hair itself, it can be caused by a disorder in the hair shaft or hair root, which we will examine below.

  • Hair disorders (diseases) related to hair roots

A problem in the hair root can cause a lot of damage to the hair tissue because the hair is nourished from the root. 

Sometimes, scalp problems also cause all kinds of hair root diseases. For example, infections caused by fungi, bacteria, or diseases such as corona may affect the scalp and cause hair loss. In some cases, itchy scalp is usually a symptom of fungal diseases that must be treated. 

In these cases, the use of antifungal shampoos and medicines prescribed by the doctor is very effective and improves the health of the scalp in a short time.

Sometimes, in some diseases, the use of certain treatments, such as cancer treatment or being in a state of nervous shock and severe stress, affects the hair root and threatens the health of the hair.

In addition, hormonal changes due to pregnancy, childbirth, menopause, and thyroid problems cause the hair roots to weaken and lose a large amount of hair. 

Diseases such as alopecia, which is related to the immune system, also cause coin and patchy hair loss, which is sometimes caused by a scalp infection. Folliculitis is another type of hair root disease that causes inflammation of the root and sometimes superficial wounds or pimples.

Of course, folliculitis occurs in all areas of the body, and sometimes, the skin may develop folliculitis after trimming body hair. 

One of its obvious signs is the formation of red pimples in the area of the hair roots. The infection caused by folliculitis, if not treated, has the possibility of spreading to other parts of the body, so it is better to be treated as soon as possible.

Some common diseases related to hair roots include:

    • Hair infection

      Some types of hair infection are contagious and can be transmitted from one person to another. For example, a type of fungal infection of the scalp causes a part of the head to become itchy and scaly in the form of a small red circle. With the growth of the circle created on the head, the hair in that part is gradually separated from the scalp and begins to fall.


    • Folliculitis:

      Bacterial infection of the hair follicle causes red bumps on the scalp but usually does not cause hair loss.


    • Alopecia:

      Alopecia is a disease that usually occurs due to immune system deficiencies in the body. In this disease, the body mistakenly does not consider the hair as a part of the body and tries to destroy it.

Various factors are involved in the occurrence of this disease. For example, if you have recently been on a strict weight loss diet, it is not unlikely that you will encounter this problem. 

Other factors, such as excessive consumption of fast food, hormonal and genetic problems, anxiety, suffering from thyroid diseases, taking blood pressure pills, etc., also increase the probability of this disease.

    • Androgenic alopecia:

      This disease, which is better known as baldness, is caused by genetic factors in more than 95% of cases. Of course, it is somewhat predictable and controllable in both men and women, but it usually progresses with age. In men, the pattern of baldness is more in the shape of the English letter M, which starts from the temples or the crown of the head.

The pattern of female hair loss also appears with thinning and regional or partial hair loss in different parts of the head.

    • Alopecia areata:

      This type of hair loss in patches is an immune disorder in which the body attacks its own hair follicles. This loss is seen in the hair of the head, but it is possible for it to happen to the eyelashes and beard as well. Hair loss can be sudden and occur in just a few days or over several weeks.

Sometimes, itching or burning occurs in the area before hair loss. Hair follicles do not die, so if the inflammation of the follicles subsides, the hair will grow back. People who experience only a few patches of hair loss often recover spontaneously and completely without any treatment.

Alopecia totalis is the name of the advanced form of this disorder in which all hair falls out.

    • Traction alopecia:

      As a result of continuous stretching of the hair, which may be caused by hair braiding or the use of elastics and hair clips, it can put pressure on the hair follicles, and as a result, the hair will fall out. In some people, traction alopecia is also caused by anxiety or bad nervous habits in putting pressure on the hair roots.

  • Telogen effluvium:

    When a person is exposed to a very stressful situation, a large number of hair follicles enter the natural telogen (shedding) phase. Fortunately, normal hair growth resumes with the start of a new hair growth cycle.

  • Anagen effluvium:

    When the hair follicles are in the anagen (growth) stage, hair may fall out, but this usually happens in people who are undergoing chemotherapy or radiation therapy for cancer. The process of such treatments is based on destroying growing and dividing cancer cells, which also destroys growing hair cells.

  • White hair

    Some people believe that frizzy hair gives them a distinctive look, but others see it as a sign of aging. Whatever you feel about gray or gray hair, you’ll eventually get it as you get older (if you still have any hair left in your old age, of course).

Scientists have tried a lot to find out the cause of gray hair and believe that they have found the root of this problem. Hair reaches its color from a pigment called melanin, which is created by melanocyte cells in hair follicles. 

Researchers have found that melanocytes are damaged over the years and eventually lose the power to produce melanin. Research has shown that DNA damage and hydrogen peroxide accumulation in follicles are possible causes of melanin production disorders. 

Without the presence of melanin, the hairs that grow have no pigment, and as a result, they become gray, white, or silver.

Some people’s hair starts turning white at a young age. Genes usually play a role when the process of hair graying starts, so if your mother’s or father’s hair turns gray early, it is likely that your hair will also turn white early. 

If you are one of those people who do not think that graying hair makes you stand out, you can easily hide it by using hair color.

    • The cause of gray hair

      Human hair begins to turn white around the age of 40 to 45, but it can also be seen at a young age.

Apart from the natural process, there are other reasons that cause graying of the head hair, including sadness and grief, fear and anxiety, nervous pressure, working too much without rest, improper nutrition, permanent constipation, lack of vitamin B, and lack of zinc and Manganese.

  • Hair disorders related to the hair shaft

Any abnormality in the structure of the hair shaft can be a type of hair shaft disease. Some hair shaft problems are easily seen with the naked eye, but others require careful microscopic examination.

The types of hair disorders related to the hair shaft are:

    • Hair leprosy

First, let’s go to the most common problem related to hair, i.e., frizz. Frizz causes the lower part of the hair to split or even split. This disease has no definitive treatment, and the only treatment is to cut the affected part of the hair.

When various factors, such as indigestion of food and digestive problems, do not reach the hair, the hair becomes frizzy. In addition, exposure to sunlight, as well as dyeing or bleaching hair, will also cause such a problem.

    • Loss of moisture in the hair texture or roughness

    • Hair that cannot be combed, hair strands grow in different directions and cannot be fixed even by combing.

    • Brittleness of hair and reduction of its tensile strength: To test the strength of hair, it is enough to gently pull the hair shaft to see if it is naturally brittle or not.


The cause of hair shaft diseases is caused by the following different things:

  • Repeated physical damage to the hair shaft
  • Genetic abnormalities
  • Excessive hair grooming
  • Stretching caused by braiding or tying hair with elastics
  • Heat from hair dryers, irons, or curlers
  • Using chemicals such as hair dyes, lotions, or hair straighteners

Usually, when the causes of hair disease are genetic, there is no specific treatment for them, but sometimes they recover on their own. Don’t forget that you can always reduce the effects of hair diseases by taking proper care of your hair.


  • Hair disorders related to the scalp

    • Dandruff

      Another common hair condition is dandruff, in which dead scalp cells become flaky and often fall onto the shoulder or clothing.

Although the flakes caused by dandruff may look similar, they are of different types and differ according to different scalp conditions. Before treating dandruff, the type of dandruff should be diagnosed.

In fact, the cause of this problem is the presence of fungi on the scalp. Of course, the presence of these fungi in itself is not a reason for dandruff; Rather, other factors, such as inflammation of the scalp, stress, anxiety, cold weather, etc., are important factors in the occurrence of dandruff.

In fact, when the environment is such that the growth of the fungus is provided, dandruff shows itself. To treat dandruff, you can use anti-dandruff shampoos that contain zinc, ketoconazole, and selenium sulfide. 

Also, consuming foods and vegetables containing vitamin B also helps control this problem. Probiotic yogurt also has beneficial bacteria and can be very useful in preventing this problem.

      • Types of dandruff:
        • Dry scalp dandruff: This type of dandruff occurs mostly in winter because the heat of the house dries the scalp and destroys its cells. Using moisturizing shampoos and coconut oil is very useful in preventing itching and treating dandruff caused by dry scalp.


        • Oily Dandruff: Sebaceous glands located under the skin produce sebum. Sebum is an oily ingredient that helps maintain moisture and protect the skin. When the sebaceous glands create too much sebum, they can make the hair greasy and stick together, thus irritating the scalp and causing dandruff. The amount of dandruff flakes in oily skin is more than in dry skin, and they tend to be more yellow than white. Regular use of anti-dandruff shampoo containing salicylic acid can help control this type of dandruff.


        • Dandruff caused by fungus: A type of fungus called Malassezia, which is found on every human skin, causes an inflammatory response in some people that leads to dandruff or even eczema. Using shampoos with compounds containing Malassezia inhibitors can be effective in treating dandruff caused by fungus.


        • Dandruff caused by disease: some common skin diseases, such as eczema or seborrheic dermatitis, also affect the scalp and cause dandruff.


    • pearl disease

      A severe drop in the quality of hair follicles causes the formation of pearl disease. This loss occurs as a result of inflammation and swelling of the scalp, and the hair that grows in such a part of the scalp is very weak and fragile. The swollen parts of the scalp suffer from hair loss, and these areas look like white pearls on the head.

    • Itchy scalp

      There are a wide range of causes for an itchy scalp. Dandruff and an inflammatory skin called seborrheic dermatitis are the most common reasons for an itchy scalp. Seborrheic dermatitis can be the result of seasonal changes, stress, hormonal fluctuations, or yeast overgrowth on the skin.

Cause of hair-related disorders

Although, in many cases, genetic issues, aging, improper nutrition, and lack of hygiene and proper hair care are among the main reasons for the occurrence of various hair diseases, you should know that many diseases also cause disturbing hair disorders

What is the most common hair disease?

Hair loss can be considered the most common hair disease that many people are looking for ways to deal with. Especially in men, hair loss is observed at a younger age than in women, and many times, it is caused by genetic factors.

What are the main causes of hair-related diseases?

Genetic, hormonal, autoimmune issues, aging, improper nutrition, and lack of hygiene and proper hair care are among the main reasons for the occurrence of various hair diseases. Changing your lifestyle, avoiding stressful situations, taking good care of your hair, and using the suit shampoo can be very useful in preventing hair diseases.


Consequently, understanding the complex balance between hair function and the various disorders it may face is critical to maintaining healthy and vibrant hair. From its essential role in regulating body temperature to its cultural significance and aesthetic appeal, hair is a truly remarkable aspect of human biology.

As you delve deeper into the realm of hair care and management, remember to prioritize both prevention and preventative measures against common disorders. Whether you’re looking for daily maintenance tips or exploring treatment options for specific conditions, knowledge is your greatest ally on your journey to hair health.

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Author and specialist

Dr. Majid Zahrabi,


  • Board Certified Neurosurgeon
  • DHA certificate holder
  • Plantation certificate holder, France
  • Certified holder of Discogol, France
  • A pioneer in the non-surgical treatment of disc herniation in the Middle East and CIS countries.
  • Under the training and coaching of Professor Jacques Theron (founder of Discogel Therapy) since 2008
  • More than 400 successful cervical and 1300 lumbar discogel injections
  • Trained and certified several neurosurgeons and spine surgeons in the Middle East and CIS countries for the treatment of Discogel
  • Strong belief in patient-centered care planning and participation
  • Neurosurgeon and spine surgeon at Imam Khomeini and Amir Mazandarani Hospital, Sari, Iran, with more than 430 surgeries annually, 2000-2011
  • Neurosurgeon and spine surgeon at Farmaniyeh, Nikan and Yas Sepid Hospital, Tehran, Iran, with more than 400 surgeries annually, 2011-2012
  • Neurosurgeon at Iranian Hospital, Dubai, 2022-2023
  • Since 2015, he has been working as a reference doctor for the treatment of intervertebral disc herniation with Discogel and has trained many doctors of spine-related specialties in various countries of the Middle East and CIS in person/practically and online.



  • Individual training sessions under the direct supervision of Professor Jacques Theron in Discogel treatment, 2008-2020
  • Training sessions under the supervision of Professor Thierry Boye on spinal implants, 2007
  • Participation and presentation in several national and international medical and neuro-spinal conferences
  • Board certificate by Iran Neurosurgery Board, 2001
  • Neurosurgery assistant training course, Isfahan University of Medical Sciences, Isfahan, Iran, 1996-2001 (In 2001, he graduated from Isfahan University of Medical Sciences with the first rank in the country.
  • His thesis the titled:The Application of human amniotic membrane in repair of dura matter in dogs.” ( It was happening for the first time in the world. )
  • General medical education, Tabriz University of Medical Sciences, Tabriz, Iran, 1984-1993


Published books:

  • CT scan of the brain for doctors
  • Etiology and treatment of painful spine disorders
  • Atlas of diagnosis, prevention, and treatment of spine disorders
  • The most common mistakes in the treatment of spinal disorders
  • Reading brain CT scan in simple language (3rd place in the book of the year)
  • Treatment of head and spine injuries

Publications and articles:

  • Bacteriostatic and bactericidal effects of DISCOGEL® (https://www.researchgate.net/)
  • Muscle recovery, reduction of pain, and improvement of movement strategies in patients with lumbar discopathy after injection of Discogel.
  • The article on the initial results of the treatment of intervertebral disc herniation with discogel injection, which won the second-best poster rank at the Pan Arab International Congress of Interventional Radiology (March 14-16, 2015) and was accepted for presentation at the Chicago Pain Congress.
  • The use of human amniotic membrane in dura mater repair in dogs, a study for the first time in the world.



  • Annual Congress of Physiotherapists of Iran, 2019
  • Chicago International Pain Congress, 2019
  • Iran International Pain Management Congress, 2018
  • Annual Congress of Physiotherapists of Iran, 2018
  • Presentation of Discogel as an innovative solution for the treatment of spinal disc herniation in Armenia for orthopedic specialists and neurosurgeons, 2017
  • First Live Workshop and Seminar on Minimally Invasive Disc Therapy (DISCON), 2017
  • Presentation of Discogel as an innovative solution for the treatment of spinal disc herniation in Azerbaijan for orthopedic specialists and neurosurgeons, 2016
  • Seminar of Iranian official managers, 2016
  • Presentation of Discogel as an innovative solution for the treatment of spinal disc herniation in Tajikistan for orthopedic specialists and neurosurgeons, 2016
  • International Neurological Intervention Congress in Iran, 2014
  • Educational seminar for nurses on treatment approaches for head and spine trauma, 2014
  • Educational seminar for general practitioners on treatment approaches for head and spine trauma, 2014
  • Speech at the Retraining Seminar for General Practitioners and Specialists in Dubai (Discon) in 2017
  • Speech in the internal retraining courses of Irani Hospital, Dubai
  • Holding lecture sessions and practical workshops on the treatment of intervertebral disc herniation with discogel injection in Azerbaijan, Tajikistan, Ukraine, Oman, and Armenia during the years 2015 to 2021.
  • Giving a lecture and holding a practical workshop for neurosurgeons in Vietnam at Ho Chi Minh City University in 2023

Dr. Majid Zohrabi started treating his patients in Dubai in 2022 and continues his activities in private medical centers in the UAE.