Final answer:
The region of a hair located outside of the medulla and containing granules of pigment is called the cortex. It is part of the hair shaft which consists of the cuticle, cortex, and medulla, and the cortex determines hair texture and strength.
Step-by-step explanation:
The region of a hair located outside of the medulla and containing granules of pigment is called the cortex. The hair shaft, which is the part of the hair we see above the skin, has three zones: the outermost zone is the cuticle, the middle zone is the cortex, and the innermost zone is the medulla. The cortex in hair is a layer of compressed, keratinized cells that provide the hair with strength and determine its texture (straight, curly) based on the shape and structure of the cortex cells relative to the shape of the hair follicle.
Hair originates in the epidermis and grows from a hair follicle. The living part of the hair is the hair root located within the follicle, while the shaft consists of dead, keratinized cells without biochemical activity, thus considered dead. The cells of the hair bulb, which are mitotically active basal cells known as the hair matrix, divide and push cells outward forming the hair shaft as the hair grows.