The central core of the hair strand that is sometimes missing in fine or very fine hair is called the?

The correct answer is the medulla, which is the central core of the hair strand. In many cases, especially with fine or very fine hair, this medulla may be absent or less developed. The medulla is typically composed of a soft, spongy substance and may appear as a series of air spaces within the hair shaft. Its presence can affect the overall characteristics of the hair, including its thickness, strength, and texture.

Understanding the structure of the hair is crucial in hair removal techniques and treatments, as the medulla plays a role in how hair responds to various removal methods. In contrast, the cortex makes up the bulk of the hair and is responsible for the hair's strength and color, while the cuticle is the outermost layer that protects the inner structures. The papilla, located at the base of the hair follicle, is essential for hair growth but is not part of the hair strand itself. Recognizing the role and presence of the medulla can greatly enhance knowledge about hair biology and its implications for hair treatment practices.