Unit 7: Ch 51 (Porth's 5th Ed) - Structure and Function of the Skin

Question 1

1. After falling off his bicycle, an 8-year-old boy has a large abrasion on his posterior thigh
   that has removed the epidermis in the region but left the dermis largely intact. Which of
   the following changes in integumentary system would be expected in the area of his
   wound?
   A) Profuse bleeding from removal of his epidermis
   B) Fewer Merkel and Langerhans cells in the region
   C) Exposure of the underlying subcutaneous tissue
   D) Removal of hair follicle roots from the area of the wound bed

Answer 1

Ans: B
Feedback:
Merkel cells and Langerhans cells are components of the epidermis. Bleeding may be
minimal since the epidermis is avascular. Subcutaneous tissue is below the dermis and
would not be directly exposed, and hair follicle roots exist at a deeper level than the
epidermis.

Question 2

2. Which of the following statements best conveys an aspect of the process of
   keratinization?
   A) Keratin cells synthesized in the dermis migrate to the surface over 20 to 30 days.
   B) Mitosis that begins with the cells of the stratum granulosum results in a continual
   supply of new keratinocytes.
   C) The stratum germinativum continuously produces new keratinocytes to replace
   losses.
   D) The basal cells of the epidermis migrate to the skin surface at a rate that matches
   superficial losses of skin cells

Answer 2

Ans: C
Feedback:
The stratum germinativum, or stratum basale, consists of a single layer of basal cells
that are attached to the basal lamina. The basal cells, which are columnar, undergo
mitosis to produce new keratinocytes that move toward the skin surface to replace cells
lost during normal skin shedding. Keratinization does not originate in the dermis or
stratum granulosum, and the basal cells of the epidermis do not migrate to the surface

Question 3

3. A nurse is teaching a client about the role that skin plays in forming a barrier to
   environmental agents and microorganisms. The nurse would recognize that which of the
   following types of cells/junctions are involved in the communication and regulation of
   the immune response and the secretions of cytokines?
   A) Gap junctions
   B) Desmosomes
   C) Adherens junctions
   D) Keratinocytes

Answer 3

Ans: D
Feedback:
Keratinocytes are now known to be active secretory cells that play an important role in
the immunobiology of the skin by communicating and regulating cells of the immune
response and secreting cytokines and inflammatory mediators. Gap junctions allow ions
and molecules to pass between skin cells, and adherens junctions provide a mechanical
connection between cells. Desmosomes are localized patches or plaques that hold two
cells tightly together by proteins called cadherins. They are terminal end points on the
cell walls of keratinocytes.

Question 4

4. While studying the skin in a science class, a student asks why all people have a pinkish
   color to their lips/mucous membranes. The instructor would respond by citing which of
   the following responses?
   A) Melanocytes are the pigment-synthesizing cells.
   B) Pheomelanin is the yellow to red pigment particularly concentrated in the lips and
   nipples of humans.
   C) Tyrosinase is responsible for all-colored cell production.
   D) A person with tiny melanocytes will have more concentrated pigment resulting in
   darker color

Answer 4

Ans: B
Feedback:
Pheomelanin, the yellow to red pigment, is found in all humans. It is particularly
concentrated in the lips, nipples, glans penis, and vagina. Melanocytes are
pigment-synthesizing cells that are scattered in the basal layer and are responsible for
skin color (not mucous membranes). Tyrosinase converts the amino acid tyrosine to a
precursor of melanin. If one has a lack of tyrosinase, the end result will be albinism. In
dark-skinned people, larger melanin-containing melanosomes are produced and
transferred individually to the keratinocyte.

Question 5

5. A 40-year-old male client has a congenital syndrome that affects the function of the
   Langerhans cells of his epidermis. The man’s care provider would expect which of the
   following manifestations of his condition?
   A) Increased susceptibility to infection
   B) High permeability of his epidermis to environmental materials
   C) Lighter skin tone than other individuals of the same ethnicity
   D) Frequent separation between the dermal and epidermal layer of his skin

Answer 5

Ans: A
Feedback:
Langerhans cells are the immunologic cells responsible for recognizing foreign antigens
harmful to the body, and they play an important role in defending the body against
foreign antigens. A lack of Langerhans cells would not manifest in increased
permeability of the skin, unexpected coloration, or separation between layers

Question 6

6. Clinical investigation of a 40-year-old female client with diverse dermatological signs
   and symptoms has focused on the woman’s basement membrane. Which of the
   following skin functions would a clinician most likely attribute to a region of the
   integument other than the basement membrane?
   A) Lack of sensory nerve impulse conduction
   B) Formation of blisters on various skin surfaces
   C) Lack of adhesion between the dermis and epidermis
   D) Large immunoglobulin deposits

Answer 6

Ans: A
Feedback:
While the basement membrane plays roles in adhering between skin layers and is a
common site of immunoglobulin deposition and blister formation, it is not a major site
of afferent nerve endings and consequent sensory transmission

Question 7

7. A person with severe lymphedema is asking the nurse where specifically are the lymph
   vessels located in the skin layers. The nurse would respond,
   A) “Basement membrane.”
   B) “Merkel cell layer.”
   C) “Subcutaneous tissue layer.”
   D) “Papillary dermis layer.”

Answer 7

Ans: D
Feedback:
Dermal papillae contain capillaries, end arterioles, and venules that nourish the
epidermal layers of the skin. This layer of the dermis is richly vascularized. Lymph
vessels and nerve tissue also are found in this layer. The basement membrane is a layer
of intercellular and extracellular matrices that serves as an interface between the dermis
and the epidermis. Merkel cells are connected to afferent nerve terminals, forming a
Merkel disk. They are believed to be neuroendocrine cells. Subcutaneous tissue consists
of fat cells and connective tissues that lend support to the vascular and neural structures.

Question 8

8. Which of the following components of immune function is absent in the dermis?
A) Macrophages
B) T cells
C) Lymph nodes
D) Mast cells

Answer 8

Ans: C
Feedback:
While macrophages, T cells, fibroblasts, and mast cells are all present in the dermis,
lymph nodes are not noted to be present in this layer.

Question 9

9. The skin is richly supplied with arteriovenous anastomoses in which blood flows
   directly between an artery and a vein, bypassing the capillary circulation. What is the
   primary significance of these structures?
   A) They regulate body temperature.
   B) They process sensory information.
   C) They control the formation of “goose bumps”
   D) They combat skin infections.

Answer 9

Ans: A
Feedback:
Anastomoses are important for temperature regulation. They can open up, letting blood
flow through the skin vessels when there is a need to dissipate body heat, or close off,
conserving body heat if the environment temperature is cold. Although goose bumps
are a reaction to cold, they are actually caused by the contraction of the arrector pili
muscles.

Question 10

10. A 51-year-old woman who was born congenitally blind and deaf is able to distinguish
    individuals by light touch of the individual’s face. Which of the following components
    of the woman’s skin innervation likely contributes the most to this ability?
    A) Ruffini corpuscles
    B) Meissner corpuscles
    C) Pacinian corpuscles
    D) Nociceptors

Answer 10

Ans: B
Feedback:
Meissner corpuscles are rapidly adapting nerve endings located on the palmar surfaces
of the fingers and hands; as such, they would be likely to be involved in fine distinction
using the fingers. Ruffini corpuscles are located in the subcutaneous tissue of hairy and
glabrous skin, while pacinian corpuscles detect gross pressure and vibration.
Nociceptors detect painful stimuli.

Question 11

11. A frustrated 26-year-old female has sought a referral to a dermatologist in an effort to
    resolve her sweating and body odor that persists despite good hygiene. Which of the
    following facts would underlie the explanation that her physician provides about her
    problem?
    A) Sebaceous secretions vary in both quantity and constituency between individuals.
    B) Excess production by eccrine sweat glands, combined with bacteria, produces a
    characteristic odor in moist areas of the body.
    C) Apocrine sweat glands produce a substance that is more oily than sweat from
    other sources.
    D) Occlusion of sebaceous glands in the axillae and groin results in proliferation of
    microorganisms

Answer 11

Ans: C
Feedback:
Body odor is the result of apocrine sweat gland secretions combining with bacteria to
produce a characteristic odor. Neither eccrine sweat glands nor sebaceous glands are
primarily involved

Question 12

12. Which of the following structures would likely be present in a hair follicle in a man's
groin but not in a follicle on his face?
A) Arrector pili muscle
B) Sebaceous gland
C) Apocrine gland
D) Hair papilla

Answer 12

Ans: C
Feedback:
Apocrine glands are only found in hair follicles in the underarms and groin. All hair
follicles contain an arrector pili muscle, sebaceous gland, and blood supply in the form
of the hair papilla.

Question 13

13. While working in an allergy clinic, the nurse notices that many patients come in with all
    types of skin reactions. The nurse working in this area knows that which cells play a
    role in the development of allergic skin condition?
    A) Langerhans cells
    B) Merkel cells
    C) Spherical melanosomes
    D) Keratin

Answer 13

Ans: A
Feedback:
Langerhans cells, the antigen-presenting cells of the epidermal skin, not only protect
against harmful pathogens but also play an important role in the development of allergic
skin conditions. Merkel cells play a role in the neuroendocrine cell function such as
neurotransmission for autonomic nerves. Spherical melanosomes are found in people
with light skin. Red hair has spherical melanosomes. Keratin is a protein that forms the
surface of the skin and is also the structural protein of the hair and nails.

Question 14

14. A man’s primary care physician has characterized his skin lesion as being a temporary
    eruption but has cautioned him against repeated rubbing or scratching as to avoid
    lichenization. What is the most likely categorization of the man’s skin lesion?
    A) A blister
    B) A corn
    C) A callus
    D) A rash

Answer 14

Ans: D
Feedback:
A rash is a temporary eruption of the skin that can result in excoriation or lichenization
if rubbed or scratched excessively. Corns, calluses, and blisters are not noted to share
these characteristics.

Question 15

15. A child comes in to show his parents (who are nurses) a blister on his foot from
    “breaking in” a new pair of shoes. The child wants to “pop the blister” to get all the
    fluid out of it, so it would not hurt so much when he puts on shoes/socks. The parents
    know that breaking the skin of the blister will put him at risk for
    A) fluid volume deficit.
    B) further edema due to loss of proteins.
    C) secondary infection.
    D) activity intolerance.

Answer 15

Ans: C
Feedback:
A blister is a vesicle or fluid-filled papule. They can have a mechanical origin caused by
friction from repeated rubbing on a single area of skin. Friction blisters most commonly
occur on the palmar and plantar surfaces of the hands and feet where the skin is
constantly exposed to mechanical trauma. Breaking the skin of a blister to remove the
fluid is inadvisable because of the risk of secondary infection. Fluid volume deficit is
highly unlikely with only one blister on the foot. The fluid in the blister is composed of
proteins but unlikely to cause a shift in fluids due to only having one blister. The child
can continue to be active but usually need a dressing/bandage placed over the blister for
comfort.

Question 16

16. Following exposure to poison oak while camping, a 20-year-old male is experiencing
    pruritus as a consequence of his immune response to irritants in the plant. What
    physiological process best accounts for his complaints?
    A) His body is communicating a low-level pain response as a protective measure.
    B) Free nerve endings are initiating an itch-specific signal to the somatosensory
    cortex.
    C) Local irritation of Langerhans cells is sending signals by way of myelinated type
    C nerve fibers.
    D) Ruffini corpuscles are transmitting the message of pruritus to the cerebral cortex.

Answer 16

Ans: B
Feedback:
It is generally agreed that itch is a sensation that originates in free nerve endings in the
skin, is carried by small myelinated type C nerve fibers to the dorsal horn of the spinal
cord, and is then transmitted to the somatosensory cortex via the spinothalamic tract.
Itching is no longer considered to be a low-level pain response. Ruffini corpuscles and
Langerhans cells are not noted to play a role in pruritus.

Question 17

17. A boy has arrived home after experiencing his first outdoor camping trip with his Boy
    Scout troupe. Upon arrival at home, he is very uncomfortable and scratching at a rash. It
    appears that he contacted poison ivy and that it has spread to many areas on his body.
    The nurse in the clinic will likely prescribe which of the following treatment measures
    for this child? Select all that apply.
    A) Prescription for corticosteroids.
    B) Cool showers especially right before bedtime.
    C) Over-the-counter antihistamines.
    D) Occlusive ointments with high petroleum content.

Answer 17

Ans: A, B, C
Feedback:
Most treatment measures for pruritus are nonspecific. Rubbing using the entire hand
helps prevent scratching. Because vasodilation tends to increase itching, cold
applications may provide relief. Cool showers before bed may be helpful. Topical
corticosteroids may be helpful in some cases. However, systemic antihistamines and
corticosteroids may be indicated for people with severe pruritus. Occlusive dressings are
thick creams that contain petroleum and can act as a barrier to prevent water loss from
the skin. They usually are prescribed for dry skin.

Question 18

18. An 81-year-old woman has noted a gradual decrease in the moisture of her skin over
    many years. Which phenomena associated with the aging process are known to
    contribute to her xerosis? Select all that apply.
    A) Separation of the basement membrane from adjacent dermal and epidermal layers
    B) Changing composition of sebaceous gland secretions
    C) Flattening of the dermal rete ridges
    D) Decreased moisture secretions from sweat glands
    E) Decrease in skin capillaries

Answer 18

Ans: B, C, D, E
Feedback:
The effects of aging on skin dryness include a change in the composition of sebaceous
gland secretions and a decrease in the secretion of moisture from the sweat glands.
Aging is also accompanied by a decrease in skin capillaries and flattening of the dermal
rete ridges resulting in less surface area for exchange of fluids between the dermis,
epidermis, and skin surface. Separation of the basement membrane is not noted to be a
normal accompaniment to aging.

Question 19

19. When trying to explain the advantages of using an emollient over other products to a
    patient suffering from dry skin, the nurse will emphasize emollients
    A) can replenish the oils on the skin surface because they contain fatty acids.
    B) will draw water out from the deeper skin layers.
    C) provide moisture-proof material to the skin by providing a thick creamy layer as a
    barrier.
    D) will contain some form of numbing agent like lidocaine to help with the itching.

Answer 19

Ans: A
Feedback:
Emollients are fatty acid–containing lotions that replenish the oils on the skin surface
but usually do not leave a residue on the skin. Humectants are the additives in lotions
that draw out the water from the deeper skin layers and hold it on the skin surface.
However, the water that is drawn to the skin is transepidermal water, not atmospheric
water. Thus, continued evaporation from the skin can actually exacerbate dryness.
Occlusive are thick creams that contain petroleum to act as a barrier. Lotions or cream
additives include steroids or mild anesthetics, such as camphor, menthol, lidocaine, or
benzocaine. These agents work by suppressing itching while moisturizing the skin.

Question 20

20. Which of the following facts accounts for the variation in skin tone that exists between
    individuals?
    A) Someone with dark skin has more melanocytes in his or her skin layers.
    B) Darker-skinned individuals have melanosomes that produce melanin faster.
    C) Dark skin is associated spherical melanosomes, which produce and
    “package” pigment differently.
    D) Greater numbers of keratinocytes result in darker skin tone.

Answer 20

Ans: B
Feedback:
The amount of melanin in the keratinocytes determines a person’s skin color.
Dark-skinned and light-skinned people have the same amount of melanocytes. However,
in dark-skinned people, larger melanosomes are produced and transferred to the
keratinocyte individually. In light-skinned people, a number of smaller melanosomes are packaged together in a membrane and then transferred to the keratinocyte. The way the
melanosomes are packaged is responsible for the pigmentation in darker-skinned
persons. Darker-skinned people do not have more melanocytes than light-skinned
people, but the production and packaging of pigment is different.