Skin Test 101*** I take no responsibility as to the accuracy of this. Further, this is by no means comprehensive.***

CHOOSE THE BEST ANSWER

1. Which of the following is the most superficial layer of the epidermis?a. Stratum Granulosumb. Stratum Lucidumc. Stratum Corneumd. Stratum Basalee. Stratum Malphigi

2. In which layer of epidermis does mitosis occur?a. Stratum Granulosumb. Stratum Basalec. Stratum Corneumd. Stratum Reticularise. Stratum Lucidum

3. Which of the following cells is NOT found in the epidermis?a. Endothelial cellsb. Merkel Cellsc. Squamous Epithelial cellsd. Langerhans Cellse. Melanocyte

4. Which of the following is NOT true of Thick Skin?a. It is generally missing the Stratum Lucidumb. It is found only on the soles of the feet and palms of the handsc. It refers to the thickness of the epidermis onlyd. Is also called glaborous skine. No hair arises from Thick Skin

5. What is the principal function of a Langerhans Cell?a. Secretory; it assists sebaceous glands in producing sebumb. Structural; it partly defines the epidermal-dermal junctionc. Absorption; it contains numerous villi to absorb ions and small moleculesd. Immunological; it participates in antigen presentatione. Temperature Regulation; it senses a change in temperature and activates a cascade to

increase or decrease bloodflow in response.

6. Which of the following proteins is incorrectly matched with its function in skin?a. Involucrin: cross-linked by transglutaminase onto the cell membrane, creating a

membrane impermeable to waterb. Filaggrin: cross-links tonofilaments in the Papillary layer of the dermisc. Oxyhemaglobin: contributes to color of skind. Keratin: family of fibrous proteins that make up intermediate filamentse. All of the above are correctly matched to their respective functions.

7. Which of the following is TRUE?a. Keratinocytes are derived from the endoderm germ layerb. Melanocytes are derived from the ectoderm germ layerc. Langerhans cells are immotiled. Merkel cells are mechanoreceptorse. NONE OF THE ABOVE are true.

8. Keratinocytes:a. Do not undergo mitosisb. Add to create a waterproof barrier in the dermisc. Are inhibited by dimethyl sulfoxide (DMSO)d. Are derived from ectoderm germ layere. Have a significant secretory function

9. The waterproof barrier formed in the epidermis is due in part to:a. Impermeability of cells due to build up of keratinb. Thickening of cell membrane due to involucrinc. Presence of glycolipids between keratinocytesd. All of the Abovee. None of the Above

10. Which of the following diseases/conditions is due to the excess proliferation of keratinocytes?a. Phemphigusb. Psoriasisc. Eczemad. Squamous Cell carcinomae. Erythema

For Questions 11-12, Refer to the diagram below:

11. Arrow A points to: a. Internal root sheathb. Cortex of the hair rootc. Medulla of the hair rootd. Bulb of the haire. External root sheath

A

B

12. Arrow B points to: a. Internal root sheathb. Cortex of the hair rootc. Medulla of the hair rootd. Bulb of the haire. External root sheath

13. Dimethyl Sulfoxide (DMSO) is hazardous to the skin becausea. It inhibits keratinocytes from actingb. It is a penetrating agent of the skin and could transport toxinsc. It inhibits development of the Stratum Basale, causing skin to “slough off”d. It is a primary cause of inflammation, indirectly causing arthritise. It inhibits intracellular proteins, causing a proliferative pathway to remain “turned on”

(thus, it is carcinogenic)

14. Which of the following is NOT true?a. The stratum lucidum contains dead keratinocytesb. The stratum granulosum begins the degenerative phasec. The stratum corneum contains sets of cells called “squames”d. The stratum basale is typically the thickest layer of the epidermise. The stratum spinosum contains cells with visible nuclei

15. Which of the following conditions (I-IV) are primarily due to melanocytes:I. PhemphigusII. AlbinoIII. NevusIV. Lamellar ichthyosis

a. I, II & IIIb. II onlyc. II, III, IVd. II, IIIe. II, IV

16. Which of the following is TRUE?a. The papillary layer is the thickest layer of the dermisb. The hypodermis is where friction ridges are presentc. Striae reflect tears in the dermisd. The dermis is unique in that it contains no collagene. Blood vessels are predominantly present in the epidermis

For questions 17-19, please refer to the diagram below:

17. The layer enclosed by the BLACK brackets is derived froma. Endodermb. Mesodermc. Ectodermd. Mesenchymee. Mucoid

18. A patient presents with edema, exudation & crusting, and severe itching (pruritis). Noticeably, there is significant inflammation to the areas affected. There are no noticeable “scales”, and the skin is staying attached well. The patient seems NOT to have significant loss of fluids. She most likely has:

a. Contact dermatitis, affecting the RED-bracketed region onlyb. Phemphigus, affecting the BLACK-bracketed region onlyc. Eczema, affecting both the RED and BLACK-bracketed regionsd. Eczema, affecting only the RED-bracketed region onlye. Psoriasis, affecting RED-bracketed region only

19. The most superficial layer of the RED-bracketed region contains which of the following cells?I. MelanocytesII. Merkel cellsIII. Endothelial cellsIV. SquamesV. Functional Keratinocytes

a. I, II, IV & Vb. I & Vc. III, IVd. IV onlye. V only

20. Which of the following is NOT involved in the formation of a melanin epidermal unit?a. Tyrosine is converted into melanin via Tyrosinaseb. Formation of premelanosomes from the golgi apparatusc. Formation of melanosomesd. Fusion of melanin granules with lysosomes in the keratinocytee. All of the above are involved in the formation of a melanin epidermal unit.

21. A correct difference between an eccrine sweat gland and an apocrine sweat gland, is that:a. Eccrine sweat glands are less common, located only in the axilla, mons pubis &

curcumanal regions; apocrine are much more common.b. Eccrine sweat glands are have a serous type of secretion, whereas apocrine have a

mucoserous typec. Eccrine sweat glands begin functioning at puberty, whereas apocrine sweat glands are

functional throughout lifed. Eccrine sweat glands have a smaller lumen than apocrine sweat glandse. All of the above.

22. Regarding innervations of the skin, which of the following is NOT accurate?a. There are six morphologically distinct types of receptors in the skinb. Merkel cells function as pressure receptors for light touchc. Both Meissner’s and Ruffini’s corpuscles are encapsulatedd. Tension is sensed by the Ruffini corpusclee. All of the above are accurate.

23. The portion of the Fingernail where keratinocytes proliferate is thea. Nail bedb. Nail matrixc. hyponychiumd. Lunulae. Nail plate

24. Periderm, refers to:a. The superficial layer of squamous epithelium which forms at 4-5 weeks of developmentb. The outermost layer of skin under the hyponychiumc. The most superficial layer of skin on the eyelid, as it is missing the stratum lucidumd. The intermediate layer of skin formed between the dermis and the hypodermise. The rarely seen but plausible layer of skin which sometimes appears in thick skin,

between the strata granulosum and spinosum

25. A fetus is captured on sonogram at 15 weeks of gestation. We would expect the skin of the fetus to contain:

a. A single layer of epiderms, as skin is just now developing and will proliferate laterb. A bilayer of epidermis, as the germinal cells have just begun replicatingc. Several layers of epidermis, constantly being replaced and expanding, but not yet fully

developedd. Normal skin (normal epidermis), with all proper layers being presente. None of the above.

26. Hypertrichosis refers to:a. Excessive hairiness due to conversion of vellus hair to terminal hair by androgens.b. Excessive hairiness due to a compensatory mechanism as sebaceous glands have poorly

developedc. Absence of nails causing excessive hairiness in compensationd. Excessive hairiness due to formation of excessive follicles or persistence of hair follicles

that normally disappear during developmente. Excessive hairiness due to failure of the hair bud to elongate.

27. Which of the following is in the correct order for normal growth (from first to last):a. Anagen, telogen, proliferationb. Anagen, catagen, proliferationc. Catagen, telogen, anagend. Telogen, catagen, anagene. Anagen, catagen, telogen

28. Eccrine sweat glands begin forming:a. Around 10-12 wks gestationb. Around 18-20 weeks gestationc. Around 7-8 weeks gestationd. Around 28 weeks gestatione. Around 3-4 weeks gestation

29. The Fingernail plate is first visible at:a. Around 12-14 wks gestationb. Around 18-20 weeks gestationc. Around 7-8 weeks gestationd. Around 27 weeks gestatione. Around 3-4 weeks gestation

30. Migration of keratinocytes from the basement membrane to the center of a wound in epidermial wound healing requires:

a. Tyrosinases, to rid melanin of the path toward the woundb. Metalloproteinases, to break hemidesmosomesc. Endothelial growth factors to be secreted by the keratinocytes as they migrated. B & Ce. A, B & C

31. A woman is rushed to the E.R. with burns on her proximal forearms, from a horrible baking accident. You and Dr. House are both present, and while he’s kicking back some Vicodin, you’re evaluating the patient. She presents with extreme pain to the proximal forearms. Upon evaluation, you discover that there is no apparent scarring or charring, but there is some blister formation. Dr. House, finally getting around to seeing the patient, states that the woman has third-degree burns, and demands (1) amputation, and (2) a martini. Setting the ethical issues aside, you:

a. Disagree with Dr. House because amputation is cruel and unusual and is never medically relevant

b. Disagree with Dr. House because the woman is suffering from first-degree burnsc. Disagree with Dr. House because the woman is suffering from second-degree burnsd. Disagree with Dr. House because, although the woman has third-degree burns, her pain

in the proximal forearm contraindicates amputatione. Always agree with Dr. House, because disagreeing with him will only bring you a

sardonic response and will possibly get you fired.

32. The mode of secretion of apocrine and eccrine sweat glands, respectively, are:a. Apocrine, merocrineb. Merocrine, merocrinec. Merocrine, holocrined. Apocrine, holocrinee. Apocrine, apocrine

33. Hair follicles are found in:a. Thick skin onlyb. Thin skin onlyc. Both Thick and Thin Skind. Neither Thick nor thin skin…their found in the hypodermise. None of the above.

-----------ANSWERS FOLLOW-----------

ANSWERS**Numbers parenthetically (#) indicate page of Dr. Crissman’s notes that correlate to correct responses. For some questions, an explanation is given.

1. C (31)2. B (30)3. A (28) – Epidermis is avascular4. A (32) – Thin skin lacks stratum lucidum5. D (33)6. B (36) – filaggrin is found in the epidermis, not the dermis.7. D (33) – Langerhans cells are motile; keratinocytes are derived from ectoderm; melanocytes are

derived from neural crest cells. 8. D (33) – Keratinocytes are not located in the dermis; have nothing to do with DMSO; do not

secrete significantly (they produce keratin, but it is stored within the cell); Can undergo mitosis (pages 34-35)

9. D (36)10. B (38)11. C (Diagrams, pp. 47, 49) 12. E (Best answer; Diagrams pp. 47, 49)13. B (39)14. D (30) – S. Basale is a single layer of cells, and thusly cannot possibly the thickest layer15. D (41-42) – Phemphigus is an autoimmune disease (38); Lamellar ichthyosis is due to

hyperkeratinization of the skin (59-60)16. C (45) – The reticular layer of the dermis is the thickest (28); Friction ridges appear in the

epidermis/dermis (43); The dermis has tons of collagen (42-44); Again, epidermis is avascular.17. D (28) – BLACK brackets indicate DERMIS; Dermis is derived from mesenchyme18. C (38) – These are the symptoms of Eczema (contact dermatitis shouldn’t produce edema and

inflammation). Eczema affects both the RED (epidermis) and BLACK (dermis) layers, as edema and infiltration of WBC’s must come from this layer. Phemphigus is ruled out in that the skin is well intact and fluid retention seems normal (outside of the edema).

19. D (37) – The most superficial layer of the EPIDERMIS is the Stratum Corneum, which contains only dead cells called squames.

20. E (40)21. D (52-53)22. E (55)23. B (53)24. A (58)25. C (diagram, page 59) – the single layer ends about 3 weeks; it’s bilayered at 4-5 weeks and

replaces from the intermediate layer starting around 11-weeks. This continues until 21 weeks, when a normal stratum corneum is present.

26. D (62)27. E (50)28. B (62)29. A (62) – The plate forms at 11-12 weeks, and is visible at 12-14 weeks on the fingers. 12-14 is the

closest correct answer.

30. B (64) – Tyrosinases are irrelevant to this process; Endothelial growth factors are released by platelets during the clot formation phase. They are not involved in the migration phase; if anything, they cause proliferation. It could be argued that they are chemotaxic factor, but still, the answer would be incorrect as keratinocytes do not release growth factors in this process.

31. C (65) – Though Choice E might be correct, for the purpose of this question, the best answer is Choice C. Blistering separates Second-degree burns from First-degree burns. Without skin charring, we cannot call this “third degree”. Amputation is somewhat irrelevant here.

32. B (52-53) – modes of both are merocrine33. B (32)