Structure And Composition Of The Hair - Honesthairfactory

Hair is composed of complex keratin fibers, which are composed of keratin molecules and intertwined with each other through spiral combinations. We cut the hair into numerous connected cross-sections, and observe the cross-sections of the hair under the microscope. We can see that each cross-section is composed of cuticle, cortex and pith. At honesthairfactory.com, we are going to tell you the structure and composition of the hair.

Everything You Need To Know About Hair Stem Structure

Hair Stem

With the deepening of the study of hair structure and properties, we have a clear understanding of hair structure. Hair is composed of a hair stem and hair root. Through the cell division of hair mother cells in the hairball, the cells rise one by one, keratinize and elongate at the same time. The life of the hair is usually 3-6 years of the growth period, then after 2-3 weeks of degradation period into the resting period, 3-4 months of red sandalwood shed. Then it closes and new hair grows from the pores. This is called hair circulation because it takes a long time, so it is very important to care for hair damage.

Hair Structure

The micrograph of the hair and the electron microscope of the hair section are composed of three layers: the epidermis area containing epidermis (capillarity) and cell membrane complex (CMC), the cortex area containing cortex (cortex) and CMC, and the bone marrow (bone marrow). The epidermis is made up of hard, flat keratins with 4-10 layers overlapping to protect the inner tissue of the hair.

CMC is to connect the epidermis between the epidermis and the epidermis, protect the hair from external physical and chemical stimulation, and prevent the hair components from flowing out. In addition, the cortex, which accounts for 85-90% of the hair, is composed of spindle cells, which are softer than the epidermis, and determine the hardness, elasticity and softness of the hair.

Hair Cuticle

The outer layer of the hair epidermis is crisscrossed by flat cells and arranged in scales from the hair root to the hair tip, wrapping the inner cortex. The main component is a kind of cross "keratin" protein, which is composed of scaly or tile-like keratinocytes. Although this membrane is very thin, accounting for only 10% - 15% of the whole hair, it has important properties. It can protect the hair from the influence of the external environment, resist external stimulation, protect sebum, inhibit water evaporation, and keep the hair dark, glossy and flexible.

The hair epidermis has strong swelling power, can effectively absorb chemical components, and close pores when meeting alkali. The epidermis is cohesive and continues the keratin fiber of the cortex, which can resist some physical and chemical effects of the outside world. If the cuticle becomes thinner, the hair will lose cohesion and resistance, and the hair will become fragile. When the sunlight enters the cells from the translucent cell membrane of the epidermis, if the hair is damaged or bifurcated, an irregular reflection will appear when the sunlight enters, giving people a rough feeling of hair.

The cuticle of the hair is composed of hard keratin, which has a certain hardness but is very brittle. It has poor resistance to abrasion. It is easy to be injured and fall off when excessively combing and using bad shampoo, making the hair dry and lusterless. Generally speaking, hair damage is the damage of the hair epidermis.

Hair Cortex

The hair cortex accounts for 75% to 90% of the hair composition. It is composed of soft keratin, which is an important part of determining the performance of hair. The hair cortex is located on the inner side of the fur surface, and is composed of many fine fibrous cells containing melanin with coagulating power. The main component of fibroblasts is keratin, which is composed of amino acids. The protein chains intertwine with each other to form fibrils. These small spiral fibrils are further aggregated into small fibrils, and then a number of small spiral fibrils form large fibrils. Finally, several large spiral fibrils combine to form fibrils that can be seen by naked eyes. The chain structure of keratin makes the hair retractable and not easy to be broken. But when the hair is wet, it is more fragile, improper traction, easy to cause damage. The hair cortex is the main component of hair. Melanin in cells is the key to determine the color of hair. 

Hair Medulla 

Located in the center of the hair, the hair medulla is a collection of hollow cells containing some melanin ions. These cell aggregates are arranged in a cubic honeycomb-like one to two side by side. Inside it is a hollow hollow structure, which contains air. These air-containing holes have the function of heat insulation and can improve the strength and rigidity of the hair without increasing the weight of the hair. Its task is to protect the hair from direct sunlight. Soft and hard hair also contains more medulla, which is 2 / 3 of the volume of hair.

The basic component of hair is keratin, which is composed of amino acids. They improve the nutrition and ingredients needed for hair growth. Various amino acid fibrils are intertwined and cross-linked through spiral and spring mechanisms, forming the strength and flexibility of keratin, thus giving the hair unique rigidity and toughness.

In natural hair, the content of cysteine is about 15% - 16%. After a perm, the content of cysteine is reduced to 2% - 3%. At the same time, there is no cysteine before perm, which indicates that perm is harmful to hair quality.