What does the term "cortical cells" refer to in hair structure?

Cortical cells refer to the cells located in the cortex, which is the middle layer of the hair shaft. These cells play a crucial role in determining the strength and texture of hair. The cortex comprises approximately 80-90% of the hair structure, contributing to its physical properties. It is within this layer that the fibrous proteins, keratin, and melanin (which gives hair its color) are structured. The arrangement and density of cortical cells directly influence how resilient and textured the hair will be, affecting its overall appearance and feel.

In contrast, while color pigment is indeed stored in the hair, it is specifically within the cortical cells where melanin resides, but this detail does not encapsulate the broader function of the cortical cells as it pertains to strength and texture. Cells responsible for hair growth are part of the hair follicle rather than the structure of the hair shaft itself. Lastly, mentioning cells found exclusively in the scalp does not accurately represent the definition of cortical cells, which are specific to the hair itself. Thus, the focus on cortical cells affecting strength and texture makes this option the most accurate in describing their role in hair structure.