1. All the following are functions of the skin except: a. excretion of body wastes b. insulation c. protection from mechanical damage d. site of vitamin A synthesis 2. The most superficial layer of the epidermis is the: a. stratum basale b. stratum spinosum c. stratum granulosum d. stratum corneum 3. These cells produce a brown-to-black pigment that colors the skin and protects DNA from ultraviolet radiation damage. The cells are: a. dendritic cells c. melanocytes d. tactile cells b. keratinocytes 4. The portion of a hair that projects from the surface of the skin is known as the: a. bulb b. matrix c. root d.) shaft 5. Circle the correct underlined term. The ducts of sebaceous sweat glands usually empty into a hair follicle but may also open directly on the skin surface.