1. Cuticle: This is the outermost layer of the hair shaft. It's made up of overlapping scales that protect the inner layers. Think of it like shingles on a roof. A healthy cuticle is smooth, reflecting light and giving hair shine.
2. Cortex: This is the middle and thickest layer of the hair shaft. It contains the protein keratin, which gives hair its strength, elasticity, and color (melanin is stored here).
3. Medulla: This is the innermost core of the hair shaft. It's not always present, especially in fine or light-colored hair. When present, it's a soft, spongy core containing air spaces and keratin. Its exact function is not fully understood.