The hair shaft is where the hair is

The part of the hair that protrudes from the scalp is the hair shaft, and the lower part of the scalp is the hair roots.

Alopecia is divided into physiological alopecia and pathological alopecia, among which, the causes of pathological alopecia are as follows:

1. Mental pressure, excessive use of the brain, staying up late, smoking, etc.

2. Genetic factors, such as hereditary topping.

3. Frequent perm and dyeing lead to damage to hair follicles.

4. The use of substandard shampoo products causes damage to hair follicles.

5. Seborrheic alopecia.

6. Nutrient trace elements.

Lack. If it is physiological alopecia, it is a normal phenomenon and there is no need to worry; If it is pathological alopecia, it needs to be targeted.

Alopecia refers to the phenomenon of hair loss, and the hair that falls out normally is in the catagen and telogen phases, and the normal amount of hair can be maintained because the hair that enters the catagen phase and the hair that has newly entered the anagen phase is constantly in dynamic balance.

Hair loss is common, with physiological and pathological factors. Physiologic factors such as postpartum alopecia and malnutrition are more common in telogen effluvium.

Excessive fatigue, or improper hair washing, resulting in hair falling out severely. Physiological hair loss can be effectively improved with daily conditioning and hair maintenance.

There is also pathological alopecia, which is common in androgenetic alopecia, seborrheic alopecia, alopecia areata, and lupus erythematosus.

Hair loss caused by various diseases such as tinea capitis. This kind of hair loss should be actively identified**, removed**and symptomatic**. In order to achieve a better ** effect.

Hair is divided into a slightly dry end, and the middle part of the hair.

The fur cortex is the main component of hair and is made up of elongated cells that run parallel to the long axis of the hair. In these cells there are about 10 mm of tensile filaments and interfibrous matrix, which determine the main physiological traits of the hair.

The filaments are composed of fibrin, 50% of which have a helical structure, and the matrix is composed of non-spirochete proteins rich in cystine. These proteins are synthesized at the lower end of the hair follicle, and cysteine, the final stage of synthesis, is converted to cystine.

The function of the sebaceous glands is to secrete sebum, which is extruded through the sebaceous ducts, and when the hair passes through the sebaceous ducts, it takes away the sebum squeezed out by the sebaceous ducts. Sebum provides natural protection to the hair, giving it shine and waterproofness.

The erector pili muscle is a small muscular organ connected to the epidermis, and depending on the external physiological environment, the erector pili muscle can stretch or contract. A drop in temperature or the action of adrenal hormones can pull the hair follicles higher and make the hair stand on end.

The physical properties of hair are related to its chemical composition. When the hair is soaked in water, it will swell quickly, and the weight after expansion is about 40% higher than the dry weight before soaking, which indicates that the hair is almost purely protein and has very little lipid. The hair has a strong duality due to the arrangement of the filaments in the cells that are parallel to the long axis of the hair.