By Hair is a filamentous biomaterial that grows from follicles found in the skin of mammals. It is composed mainly of a protein called keratin, which is also found in the outer layer of the skin and nails. Hair serves various functions, including protection, insulation, and sensory purposes.
Here are some key points about hair:
Hair Growth: Hair grows from hair follicles, which are small, tube-like structures embedded in the skin. The rate of hair growth varies among individuals, but on average, hair grows about half an inch (1.25 cm) per month. The growth cycle of hair consists of three phases: anagen (growth phase), catagen (transition phase), and telogen (resting phase).
Hair Structure: Each strand of hair is made up of three layers. The innermost layer is the medulla, followed by the cortex, which contains the pigment responsible for hair color. The outermost layer is called the cuticle, which is a protective layer of overlapping cells that help prevent damage to the hair shaft.
Hair Types: Human hair can be broadly categorized into three main types based on its shape and texture: straight, wavy, and curly. The structure of the hair follicle determines the hair type. Additionally, hair can vary in thickness, density, and color, which is determined by the presence and distribution of melanin pigment.
Hair Color: Hair color is determined by the type and amount of melanin present in the cortex of the hair shaft. Two types of melanin contribute to hair color: eumelanin (which produces black and brown colors) and pheomelanin (which produces yellow and red colors). The combination and distribution of these pigments determine the range of hair colors observed in individuals.
Hair Care: Proper hair care involves maintaining cleanliness, protecting from damage, and promoting overall hair health. This includes regular washing with suitable shampoos, conditioning to moisturize and detangle, protecting from excessive heat and sunlight, and avoiding excessive use of styling products or harsh treatments that can damage the hair.
Hair Loss: Hair loss or alopecia can occur due to various factors, including genetics, hormonal changes, nutritional deficiencies, certain medications, autoimmune conditions, and excessive hairstyling or pulling. There are different types of hair loss, such as male pattern baldness, female pattern hair loss, alopecia areata, and telogen effluvium.
Hair in Culture: Hair holds cultural and social significance in many societies. Hairstyles and haircuts often reflect individual style, cultural traditions, or societal norms. Hair can be styled in various ways using different techniques, tools, and products to achieve desired looks.