B: The epidermis is continually replaced as new cells from the stratum basale move the overlying cells more superficially until eventually the stratum corneum flakes off. If the ink is placed below the stratum basale of the epidermis into the dermis, it remains there and can be seen through the translucent epidermis.

C: UV light converts cholecalciferol (= provitamin D3) into vitamin D precursor. The liver then adds a hydroxyl group.

A: The prefix “trans” implies crossing the skin to be absorbed into the bloodstream, rather than affecting the skin onto which it is applied. “Topically” is reserved for the latter type of administration.

C: Stratum corneum is the outermost dead layer of the epidermis.

D: The cells of the stratum corneum are dead, having lost all of their organelles and being filled with keratin.

D: Choice A is incorrect as fat is not stored. Choice B is incorrect as bile is not excreted. Choice C is incorrect as lymphocytes are not produced.

A: Sudoriferous glands secrete sweat. Sebum (or oil) is produced by sebaceous glands.

D: “Hypo” means below, in this case, the dermis. Subcutaneous fat (superficial fascia) lies beneath the dermis.

B: Melanin causes the skin to darken (tan) which absorbs some of the incoming UV radiation.

C: Endocrine is a general term for glands that produce hormones. Merocrine is another name for eccrine.

C: Dendrocytes are able to engulf bacteria and debris. The melanocytes and keratinocytes of the skin produce melanin and keratin, respectively, while Merkel cells are a sensory structure.

A: Epidermis refers to the outermost layer of the skin. While stratum germinativum is part of the epidermis, it is the deepest part.

B: Dietary calcium requires vitamin D for absorption.

C: Eccrine sweat glands secrete through a duct, and apocrine sweat glands secrete into a hair follicle.

B: The waterproof outer layer of the epidermis is lost if skin is burnt off, so evaporation from the wet tissues beneath proceeds rapidly