The outermost, tough portion of a hair shaft is the
A)cortex.
B)cuticle.
C)medulla.
D)soft keratin.
E)external root sheath.

Question

Quizplus · Accepted Answer

The cuticle is the outermost layer of a hair shaft and is composed of flattened, keratinized cells that overlap like shingles on a roof to provide protection and smoothness to the hair. The cortex is the middle layer of the hair shaft and contains melanin pigment and structural proteins. The medulla is the innermost layer and contains soft keratin. The external root sheath is the extension of the epidermis that surrounds the hair follicle. Soft keratin refers to the type of keratin found in the medulla, not the outermost layer of the hair shaft.

The Outermost, Tough Portion of a Hair Shaft Is the