Which layer is the innermost portion of the hair shaft?

Which layer is the innermost portion of the hair shaft?

• A. Cortex
• B. Cuticle
• C. Papilla
• D. Medulla

Answer: (D)

The innermost portion of the hair shaft is the medulla. It sits at the very center, composed of loosely packed cells and sometimes air spaces. The medulla is not present in all hairs, especially very fine ones, but when it exists, it forms the core inside the shaft. Surrounding the medulla is the cortex, which provides most of the hair’s strength and color, and outside of that is the cuticle, a protective outer layer of overlapping cells. The papilla, located at the base of the hair follicle, nourishes the growing hair and is not part of the shaft itself.

The innermost portion of the hair shaft is the medulla. It sits at the very center, composed of loosely packed cells and sometimes air spaces. The medulla is not present in all hairs, especially very fine ones, but when it exists, it forms the core inside the shaft. Surrounding the medulla is the cortex, which provides most of the hair’s strength and color, and outside of that is the cuticle, a protective outer layer of overlapping cells. The papilla, located at the base of the hair follicle, nourishes the growing hair and is not part of the shaft itself.