Review Questions

15. In humans, exposure of the skin to sunlight is required for ________. a. vitamin D synthesis b. arteriole constriction c. folate production d. thermoregulation

A. vitamin D synthesis

13. Sebaceous glands ________. a. are a type of sweat gland b. are associated with hair follicles c. may function in response to touch d. release a watery solution of salt and metabolic waste

B. are associated with hair follicles.

23. After a skin injury, the body initiates a wound-healing response. The first step of this response is the formation of a blood clot to stop bleeding. Which of the following would be the next response? a. increased production of melanin by melanocytes b. increased production of connective tissue c. an increase in Pacinian corpuscles around the wound d. an increased activity in the stratum lucidum

B. increased production of the connective tissue

19. If you cut yourself and bacteria enter the wound, which of the following cells would help get rid of the bacteria? a. Merkel cells b. keratinocytes c. Langerhans cells d. melanocytes

C. Langerhans cells

21. Bedsores ________. a. can be treated with topical moisturizers b. can result from deep massages c. are preventable by eliminating pressure points d. are caused by dry skin

C. are preventable by eliminating pressure points

7. The papillary and reticular layers of the dermis are composed mainly of ________. a. melanocytes b. keratinocytes c. connective tissue d. adipose tissue

C. connective tissue

17. An individual using a sharp knife notices a small amount of blood where he just cut himself. Which of the following layers of skin did he have to cut into in order to bleed? a. stratum corneum b. stratum basale c. papillary dermis d. stratum granulosum

C. papillary dermis

9. Which of the following is not a function of the hypodermic? A. protects underlying organs B. helps maintain body temperature C. source of blood vessels in the epidermis D. a site to long-term energy storage

C. source of blood vessels in the epidermis

11. The hair matrix contains ________. a. the hair follicle b. the hair shaft c. the glassy membrane d. a layer of basal cells

D. a layer of basal cells

5. The papillary layer of the dermis is most closely associated with which layer of the epidermis? A. stratum spinosum B. stratum corneum C. stratum granulosum D. stratum basale

D. stratum basale

29. Why do people sweat excessively when exercising outside on a hot day?

Sweating cools the body when it becomes warm. When the body temperature rises, such as when exercising on a hot day, the dermal blood vessels dilate, and the sweat glands begin to secrete more sweat. The evaporation of the sweat from the surface of the skin cools the body by dissipating heat.

25. What determines the color of skin, and what is the process that darkens skin when it is exposed to UV light?

The pigment melanin, produced by melanocytes, is primarily responsible for skin color. Melanin comes in different shades of brown and black. Individuals with darker skin have darker more abundant melanin, whereas fair-skinned individuals have a lighter shade of skin and less melanin. Exposure to UV irradiation stimulates the melanocytes to produce and secrete more melanin.

31. Why do teenagers often experience acne?

Acne results from a blockage of sebaceous glands by sebum. The blockage causes blackheads to form, which are susceptible to infection. The infected tissue then becomes red and inflamed. Teenagers experience this at high rates because the sebaceous become active during puberty. Hormones that are especially active during puberty stimulate the release of sebum, leading in many cases to blockages.

27. Explain the differences between eccrine and apocrine sweat glands.

Eccrine sweat glands are all over the body, especially the forehead and palms of the hand. They release watery sweat, mixed with some metabolic waste and antibodies. Apocrine glands are associated with hair follicles. They are larger than eccrine sweat glands and lie deeper in the dermis, sometimes even reaching the hypodermis. They release a thicker sweat that is often decomposed by bacteria on the skin, resulting in unpleasant odor.