What are the 3 main structures of the hair follicle?

The appendage that projects from the epidermis is known as the hair shaft. The hair shaft is comprised of three layers: the cuticle, cortex, and medulla.

The cuticle is the hair’s outer most layer which has shingle or scale like cells that overlap. These cells work defensively to prevent damage to the hair’s inner structure and to control water content of hair fiber. The middle structure includes the cortex which provides strength, color and texture of the hair. The innermost structure is the medulla layer which is only present in large thick hairs. The shingle like cells of the cuticle layer point toward the ends of the hair and are raised during chemical processes. When the cells are raised, solutions are able to enter into the cortex layer.

The improper use of tools, heat, excessive manipulation and chemical over-processing can cause damage to the cuticle layer of the hair, weakening the integrity of the hair. To prevent hair damage, take a proactive approach to healthy hair care by scheduling an appointment with a licensed stylist.

The middle layer of the hair is known as the cortex, and it has many different functions. Approximately 90 percent of hair’s total weight lies within the cortex layer. Elongated cells form a fibrous substance that gives strength and elasticity to the hair. The cortex also houses the pigment (melanin) that gives hair its natural color. Services such as chemical hair relaxing, thermal styling, wet setting and hair coloring oxidation cause temporary and permanent changes to the hair. These changes take place in the cortex layer.

There are two types of melanin that can be found in the cortex layer of the hair: eumelanin and pheomelanin. Eumelanin produces brown and black color, and is the most prevalent type of melanin. Pheomelanin imparts yellow, blonde, red and auburn hues. Natural hair color derives from a peomelanin and eumelanin ratio combined with the size and number of pigment granules. When hair is gray, there is an absence of melanin pigment in the cortex layer.

The medulla, also referred to as the pith or marrow of the hair, is the innermost layer. Composed of round cells, this layer is normally found in thick and/or coarse hair. Naturally blonde and fine hair generally does not have a medulla. The function of this layer of hair does not affect the hair care services conducted by salon professionals.

Beneath the epidermis is a factory of structures working together to promote hair growth. The hair root, the portion of hair underneath the scalp’s surface, works with the dermal papilla, hair bulb, arrectorpili, sebaceous or oil gland and follicle in the formation of hair.

The dermal papilla contains the blood supply and nerves that produce nutrients for the hair. These vital nutrients are needed in order for hair to grow. The dermal papilla is shaped similar to a cone and sits inside the hair bulb.

The hair bulb is another important factory producer. It is located at the base of the hair strand, and its shape is like a club. It acts as a cover for the dermal papilla.

The arrectorpili is a familiar hair factory worker. Its colloquial name is goose bumps. This small muscle fiber lives in the bottom of the hair follicle. Changes in temperatures and fear often cause the muscle fiber to contract, making hair stand straight up. The results, goose bumps, last a few seconds.

The oil glands of the skin are called sebaceous glands. These glands are connected to the hair follicle and secrete sebum, an oily substance that lubricates the hair.

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What are the 3 main structures of the hair follicle?

Trichology Talks

Your hair has a fascinating structure. It has three distinct layers, and is made up of amino acids (proteins) held together by chemical bonds.

Each of your hairs grows from its own individual hair follicle. The hair bulb is situated at the base of each hair follicle, and contains your growing hair cells. These continually divide and push upwards, gradually hardening. When they reach the upper part of the bulb, they arrange themselves into six concentric layers. The three inner layers become the hair, made up of the cuticle, the cortex and the medulla (although the medulla isn’t always present, especially in hairs with a thinner diameter). The outer three layers become the lining of the follicle.

Specific cells in the hair bulb, called melanocytes, make the pigment called melanin that gives your hair its colour.

The shape of your hair follicle determines the shape of your hair (i.e. whether it is straight, wavy or curly).

Your hair shaft is the part of your hair that can be seen above your scalp. It is made of a protein called keratin, compacted and fused together.

Keratin is the same material that nails, hoofs, feathers and claws are composed of.

Keratin is a remarkably strong protein, very resistant to wear and tear. It is held together by two kinds of bonds: disulphide bonds and hydrogen bonds.

Disulphide bonds are extremely durable. In fact, they are one of the strongest naturally occurring bonds in the world. When you perm it or relax your hair, these disulphide bonds are broken, and reset into a different configuration. This is what allows you to permanently change the shape of your hair.

Hydrogen bonds are weaker and more numerous than disulphide bonds. They help give your hair its flexibility. When you wet your hair, they are easily broken and can be temporarily reset with heat until they become wet again (either from water or humidity). This is what allows you to style your hair with hair dryers and tongs after washing.

Your hair shaft consists of three layers

The Cuticle

The cuticle is your hair’s protective layer, composed of overlapping cells — like fish scales or roof tiles, but facing downwards. A healthy cuticle is smooth and flat. This gives your hair shine and protects the inner layers from damage. It also minimises the movement of moisture in and out of the underlying cortex, thus maintaining your hair’s hydration balance and flexibility. However, chemical processes and weathering can lift the cuticle and disrupt this balance, causing your hair to become dry and brittle.

The Cortex

The cortex forms the main bulk and pigment (colour) of your hair. It consists of long keratin filaments, which are held together by disulphide and hydrogen bonds. The health of your cortex depends largely on the integrity of the cuticle protecting it.

The Medulla

The medulla, only present in thicker hair types, is the innermost layer of your hair. It consists of a soft, thin core of transparent cells and air spaces.

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What is the basic structure of the hair follicle?

A hair follicle is a tube-like structure (pore) that surrounds the root and strand of a hair. Hair follicles exist in the top two layers of your skin. You're born with over 5 million hair follicles in your body and over one million hair follicles on your head. As you age, hair grows out of your hair follicles.

What are the 3 follicle cycles of hair growth?

This cycle can be divided into three phases: anagen (growth), catagen (transition), and telogen (rest). Anagen growth is the active phase in which the hair follicle takes on its onion-like shape and works to produce the hair fiber.