The skin is the largest organ because it covers the whole body. Its two major parts include the epidermis and the dermis.
The epidermis consists of five layers. The outermost layer, or your skin’s surface, is made up of dead cells, while the innermost layer is responsible for cell generation. When new cells grow and divide from the innermost layer, they push older cells upward until they become your skin’s surface. The dermis, which is found below the epidermis, contains your skin cell’s nutrient-supplying blood vessels.
Hair starts deeply from the human skin. And hair growth cycle has three stages. The anagen phase starts with a hair follicle – the unseen part of hair located in your dermis. The anagen phase usually lasts for six years, which makes it possible to grow your hair longer. Ninety percent of your present hair undergoes this stage.
The hair follicle has several parts:
- Bulge. This is where stem cells come from.
- Outer root sheath. This is the passage of the stem cells to the dermal papilla.
- Dermal papilla. This part gives nourishment to stem cells to start hair growth.
- Sebaceous glands. These glands are located beside the bulge. They release sebum, which helps the transport of stem cells from the bulge to the derma papilla.
- Hair bulb. This is the formed structure of the growing cells or the starting point of hair growth. Melanocytes are the cells in the hair bulb that produce melanin, which gives hair its color.
Meanwhile, the visible hair on your skin is called the hair shaft. It has three parts:
- 1.Cuticle. These are the outermost 6 to 11 layers made up of overlapping semi-transparent keratin scales. The cuticle protects your cortex by minimizing the lost of moisture and by keeping the bond of your hair shaft and hair follicle.
- 2.Cortex. This is the middle layer made up of long keratin filaments (disulfide and hydrogen bonds). The cortex provides the texture, color, flexibility, and strength of your hair.
- 3.Medulla. This is the innermost layer made up of air spaces and keratin transparent cells. This is present in thick and large hairs.
The second stage is called the catagen phase, or the stoppage of hair growth. Follicle cells die, causing the hair shaft to detach from the germinal matrix. This cycle lasts for 2 to 3 weeks, and only 1% of your present hair undergoes this stage.
The last stage is called telogen, or the 3 to 4-month rest of the hair follicle from hair growth. This happens to 10% of your hair, where the outer root sheath remains connected to the dermal papilla.
This growth cycle repeats, depending on the human body. This shows that frizzy hair is inevitable, especially during the catagen phase as the shaft disconnects from the cell-generating part. However, there are still external factors which contribute to frizzy hair.