The innermost part of the hair (medulla) and the outside layer of the hair (cuticle) do not react with hair dye.
It's called the lower mantle.
The innermost part of an object is called its core.
The innermost layer of a carrot is called the core or heart. This part of the carrot is typically darker in color and has a slightly different texture compared to the rest of the carrot.
The medulla is the inner most layer of hair.
The innermost and hottest part of the sun is called the core. It is where nuclear reactions occur, producing immense heat and energy through the fusion of hydrogen atoms into helium.
Connective Tissue Sheath
The term "medulla" is used for different parts of the body because it simply means "middle" or "central" in Latin. The medulla in the hair may refer to the innermost layer of the hair shaft, while the medulla in the brain refers to the lower part of the brainstem responsible for regulating basic bodily functions like breathing and heart rate.
The three main layers of the hair shaft are the medulla (innermost layer), cortex (middle layer), and cuticle (outer layer). The medulla is the innermost part of the hair shaft, often absent in fine hairs. The cortex provides strength, color, and texture to the hair, while the cuticle is the protective outer layer made up of overlapping scales.
Hair Shaft
the innermost part of something
The innermost part of a flower is the carpel, which is the female reproductive organ. It consists of the stigma, style, and ovary, where the ovules are located.