Hair located at different of body including scalp hair are a part of integumentary system of our body. It is the most important and natural part of our body which aids to overall look and personality. Almost, entire exterior surface of our body is covered with hairs except a few places like the palms of hands or the soles of feet.
Each hair is consisting of the following parts –
- Hair shaft – It is the visible part of the hair that extends out of the skin.
- Hair bulb or root – At the base of hair, it widens like a bulb called hair root. It is situated under the skin and extends down to the deeper layers of the skin.
- Papilla – The hair papilla supply blood to the root. It is found inside the bottom of the hair bulb. New hair cells are constantly being made in the hair bulb, close to the papilla.
- Follicle – Hair root is surrounded by the hair follicle which is a sheath of skin and connective tissue. Follicle is also connected to sebaceous oil glands.
- Arrector Pili – Each hair follicle is attached to this tiny muscle which monitors the hair stand up.
- Nerve ends – Many nerve ends are situated at the hair follicle. These nerves sense hair movement and are sensitive to even the slightest draft.
Hairs, which grow and located at different parts of our body performs different functions –
- Scalp Hair improves our overall look and personality. Scalp hair helps to keep the sun rays from reaching to our head.
- Eyelashes and eyebrows hair keep dust, dirt and sweat out of our eyes.
- Hairs in our nose / nostrils and ears help to keep out germs, dirt and other foreign particles to enter in our body.
- Hair on limbs and other body parts helps to regulate our body temperature.
- Hairs stand up when it is too cold. This is because of contraction of tiny muscles called Arrector pili present at the root of each hair. Thus skin get distorted to create goosebumps. This is called piloerection. It is the characteristics of all mammals to use hair or fur to trap an insulating warm air layer above skin to save from cold.
Growth of scalp hair has following properties –
Hair bulb constantly produce new cells which gradually stick together and harden. The full strand of hair develops from this group of hardened hair cells. Because new hardened cells keep on attaching to the hair from below, it is gradually pushed up out of the skin. In this way a single hair on your head grows at a rate of about 1 cm per month.
Facial hair, and especially eyelashes, eyebrows and body hair grows at a slower pace.
The color of scalp hair is determined by the amount of melanin present in the hardened cells of hair shaft. This varies with the age and also from person to person. The amount of melanin typically decreases as people get older. It then loses its color and turns white.
Hair growth can be divided into three phases –
As long as new hair cells continue to grow in the hair bulb, the hair continues to grow longer. This is called Anagen or Growth phase. At any point of time, about 90 % of total visible hair oh body surface is in this growth phase.
Length of growth phase depends on location of hair. Scalp hair growth phase lasts for several years. So it can grow more than a meter in length if not cut. The growth phase is short for hairs at eyelashes, eyebrows, nasal hair and ear hair.
In this phase, hair roots separate from the papilla. It is a transitional phase that last for about two to four weeks.
In telogen or resting phase, the hair gets separated completely from the papilla and thus supply of blood is cut off. Hair is gradually pushed out of the skin by new growing hair. The older hair in resting phase eventually falls out. This resting phase can last for several months.
Human body constantly lose hair because of the resting phase and then fall out by pushing up of newly growing hair. A healthy adult human lose about 70 to 100 hairs from head every day. As new hairs are always growing and replacing them, this natural hair loss is a normal case.
The rate of hair loss become abnormal if the hair roots are damaged during the growth phase or if more hairs go into the resting phase. If no new hair grows in replacement, that part of the skin becomes bald. This type of hair loss is referred to as alopecia. Baldness may be temporary or permanent.
The main causes of increased hair loss or baldness is summarized as follows –
- Hereditary cause – One of the most common reasons for increased hair fall is genetic or hereditary. It is commonly known as androgenic alopecia.
- Aging – As we grow up, rate of hair growth slows down. At a stage, hair follicles stop growing hair, causing hair thinning. At this stage, hair also starts to lose its color.
- Hormonal changes & Medical conditions – A variety of medical conditions can cause permanent or temporary hair loss. Such as hormonal changes due to pregnancy, childbirth, menopause and thyroid problems.
- Medications and supplements – Hair loss may be a side effect of certain drugs, such as chemotherapy those used for cancer and drugs used for arthritis, depression, heart problems, gout and high blood pressure.
- Radiation therapy to the head – After radiotherapy to the head, hair may not grow back as the same as it was before.
- Poor hair care – Hair also requires special treatment and care. This includes oiling, regular washing, conditioning and more.
- Lifestyle – A happy and cheerful life leads to healthy strong hair and a stressful life event can cause general thinning of hair. This type of hair problem is temporary and reversible.
- Hair styling – Most frequent hair styling is one of the major causes of hair fall. Pulling hair tight in a pigtail or cornrows can cause traction alopecia, a type of hair fall. Even heat treatments to straighten or curling hair can cause hair fall.
- Pollution and weather – The pollution and adverse weather conditions may cause scalp irritation, dandruff, itching and hair fall.
Various diseases causing to hair fall are –
- Alopecia areata – It is round patches of total hair loss from the scalp. The cause of alopecia is not known and re-growth of hair happens.
- Baldness – It is the most common type of abnormal hair loss in men. It is also known as “Male pattern baldness”.
- Dandruff – A mild inflammation of the scalp resulting in scaly and itching skin and flake off. Seborrheic dermatitis may also affect the ears and face.
- Tinea capitis – A ringworm fungal infection of the scalp resulting in round patches of hair loss.
- Trichotillomania – A mental disorder that includes the irresistible urge to pull out self hair. Its cause is unknown.
- Lice – These are the tiny insects that live on the scalp and feed on blood. Children are most susceptible to catching these insects.
- Postpartum alopecia – It is a hair loss after delivering a baby and usually resolves without any treatment.
- Folliculitis – Inflammation of hair follicles due to an infection caused by a bacteria called Staphylococcus aureus. Acne is another form of folliculitis that is caused by bacteria called Propionibacterium acnes.
- Hirsutism – A typical condition in which women develop male type of facial hair. This may cause due to an excess of testosterone by medical conditions.
Like other body organs, our hair also need intensive care. A few tips for healthy hair are –
- Cleaning of scalp – Always clean the scalp. If cleaning is not done properly, dirt, sweat and impurities can clog hair follicles. This results in reduced supply of blood and nutrients to follicles leading to poor hair growth and hair fall.
- Use Hair Conditioners – Conditioning of hair improves the look, feel, manageability and appearance of hair. Conditioning reduces the friction between hair strands and allows smoother combing, which can otherwise cause damage to hair.
- Avoid hair heat styling – Constant heating and drying procedures can weaken hair protein and can lead to weakness and fragility that causes hair loss.
- Use shampoo – Avoid using soaps and detergents to wash hair. A shampoo is a regular friend of our hair. A hair friendly shampoo should contain vitamin B3 (niacin), pro-vitamin B5 (panthenol) and B7 (biotin) with other natural ingredients. It should be free from silicon, sulphate and paraben.
- Avoid tight hairstyle – Minimize the use of hair accessories. If necessary use hair clips with rubber padding, hairpins with balled ends, and fabric hair ties instead of rubber bands.
- Exercise – Exercise is as good for healthy hair as for body. It helps in increase in the blood flow with nutrients and oxygen in the scalp. Cardiovascular exercises are useful and can lead to healthy hair.
- Enriched Nutrition – Nutrient plays an important role in hair growth. For stronger and healthier hair, proteins, fruits, green veggies, vitamins, and iron-rich food should be in our diet.