While lecturing about frostbite, the instructor asks the students, "Which substance prevents undue evaporation from the stratum corneum during the cold winter weather which then helps conserve body heat?" The most correct student answer is:

Question

A) A Langerhans cell, which produces antigen-presenting cells
B) An eccrine sweat gland
C) A nerve ending
D) Sebum, secreted by the sebaceous gland

Answer 1

Ans: D
Feedback:
Sebum lubricates the hair and skin, prevents undue evaporation of moisture from the stratum corneum during cold weather, and helps to conserve body heat. Langerhans cells are dendritic cells that reside principally in the stratum spinosum of the epidermis and play a major role in the functioning of the skin's immune system. Their major function is to phagocytose and process foreign antigens. Most hair follicles are associated with sebaceous glands, and these structures combine to form the pilosebaceous unit. Langerhans cells are not paired with hair follicles, and apocrine, not eccrine, glands are often associated with a hair follicle. Nerve endings are widely distributed throughout the skin, but these are not paired with hair follicles.