1. Hair Shaft: The hair shaft is the visible part of the hair that extends above the skin's surface. It is composed of three layers: the cuticle, cortex, and medulla (in some hairs). These layers give the hair its strength, color, and texture.
2. Stratum Corneum: This is the outermost layer of the epidermis, which is the topmost layer of the skin. The stratum corneum is made up of dead skin cells that are continuously shed and replaced. It acts as a protective barrier, helping to prevent water loss and shielding the body from external elements.
3. Epidermis: The epidermis is the top layer of the skin and serves as a protective barrier between the body and the external environment. It consists of several layers of cells, each with specific functions. The deepest layer of the epidermis contains cells that actively divide and produce new cells, which then move up through the layers as they mature.
4. Vein and Artery: Veins and arteries are part of the circulatory system. Veins carry oxygen-depleted blood back to the heart, while arteries carry oxygen-rich blood away from the heart to various parts of the body. Blood vessels play a crucial role in supplying nutrients and oxygen to the cells, including those in the hair follicles.
5. Sebaceous Gland: Sebaceous glands are attached to hair follicles and produce sebum, an oily substance. Sebum helps moisturize the skin and hair, preventing excessive drying. It also plays a role in maintaining the health of the skin's microbiome and provides some protection against harmful microorganisms.
6. Dermis: The dermis is the second layer of the skin, located beneath the epidermis. It contains a variety of structures, including blood vessels, nerves, hair follicles, and sebaceous glands. The dermis provides support and nourishment to the epidermis and its appendages, such as hair.
7. Hair Bulb: The hair bulb is the base of the hair follicle, located in the dermal layer of the skin. It is the actively growing part of the hair and contains matrix cells that divide and produce new hair cells. The dermal papilla, a cluster of cells at the base of the hair bulb, supplies nutrients and oxygen to support hair growth.
The interplay of these components creates the structure of hair and its associated functions. The hair shaft's layers contribute to its strength and appearance, the sebaceous gland and dermal papilla play roles in nourishing and supporting hair growth, and the epidermis and its outermost layer offer protection to both the skin and hair. Blood vessels supply essential nutrients to these structures, ensuring their proper function and health.