Final answer:
The two primary parts relevant to hair care are the hair fiber, also known as the hair shaft, and the hair follicle. The hair matrix within the follicle, including the hair root, bulb, and papilla, plays a critical role in hair growth and health. The hair fiber is what is visible and is composed of dead, keratinized cells.
Step-by-step explanation:
The two primary parts of hair care are the hair fiber and the hair follicle. The hair fiber, also known as the hair shaft, is primarily made of dead, keratinized cells and is the part that is visible above the skin's surface. The hair follicle, on the other hand, is the structure from which hair originates. It is embedded within the skin's dermis and extends into the epidermis.
At the base of the hair follicle lies the hair root, which is the living part of the hair. Deep in the dermis, at the hair root, you'll find the hair bulb and the hair matrix. The hair matrix contains a layer of basal cells that are responsible for the growth of the hair fiber, and hence could be considered a critical part of hair care from a biological standpoint.
The hair papilla, which is surrounded by the hair bulb, is made of connective tissue and contains blood capillaries and nerve endings that feed the cells in the hair matrix. While the hair papilla itself is not a part of the hair fiber, it is essential for the growth and health of the hair follicle and consequently the hair that grows from it.