Q: Which formula best represents the relationship between UV exposure, melanin production, and vitamin D synthesis?

$UV_{exposure} \rightarrow \text{Melanin production} \uparrow \rightarrow \text{Vitamin D synthesis} \downarrow$

Q: Which equation best describes the time required for a keratinocyte to migrate from the stratum basale to the stratum corneum?

$t_{migration} \approx 40-50 \text{ days}$

Question 1

Which layer of the epidermis is only present in thick skin, such as the palms of the hands and soles of the feet?

Accepted Answer

Stratum lucidum

Question 2

A patient presents with a bluish discoloration of the skin (cyanosis). Which physiological condition is most likely responsible for this appearance?

Accepted Answer

Extremely low oxygen bound to hemoglobin

Question 3

Which cell type in the epidermis is responsible for producing the pigment that protects DNA from UV radiation?

Accepted Answer

Melanocyte

Question 4

Fingerprints are formed by which anatomical feature of the skin?

Accepted Answer

Prominent dermal papillae arranged into dermal ridges

Question 5

Which type of sweat gland is most prevalent and is responsible for thermoregulation through watery secretion?

Accepted Answer

Eccrine gland

Question 6

A person living near the equator is more likely to have darker skin due to increased melanin production. What is the evolutionary advantage of this adaptation?

Accepted Answer

Prevention of excess vitamin D production

Question 7

Which accessory structure of the skin is derived from epithelial tissue and is involved in protection and sensory functions?

Accepted Answer

Hair

Question 8

Which of the following best describes the process of holocrine secretion in sebaceous glands?

Accepted Answer

Cell rupture and release of oily lipids

Question 9

A patient presents with scaly plaques on the head and neck that may ulcerate and bleed. Which type of skin cancer is most likely?

Accepted Answer

Squamous cell carcinoma

Question 10

Which formula best represents the relationship between UV exposure, melanin production, and vitamin D synthesis?

Accepted Answer

$UV_{exposure} ightarrow 	ext{Melanin production} \uparrow ightarrow 	ext{Vitamin D synthesis} \downarrow$

Question 11

Which cell type in the stratum spinosum acts as a phagocyte and is important for immune defense?

Accepted Answer

Dendritic cell (Langerhans cell)

Question 12

A patient with vitiligo has patches of skin with decreased pigmentation. What is the underlying cause?

Accepted Answer

Autoimmune destruction of melanocytes

Question 13

Which layer of the dermis is responsible for tension lines and is important in wound healing and scarring?

Accepted Answer

Reticular layer

Question 14

Which pigment is responsible for the orange-red coloration of the skin and is obtained from the diet?

Accepted Answer

Carotene

Question 15

A third-degree burn is characterized by which of the following?

Accepted Answer

Destruction of epidermis, dermis, and possibly deeper tissues

Question 16

Which equation best describes the time required for a keratinocyte to migrate from the stratum basale to the stratum corneum?

Accepted Answer

$t_{migration} \approx 40-50 	ext{ days}$

Question 17

Which skin marking is caused by gaps between collagen bundles in the reticular layer of the dermis?

Accepted Answer

Tension lines

Question 18

Which of the following is a secondary function of melanin in the skin?

Accepted Answer

Reduces synthesis of vitamin D in response to UV radiation

Question 19

Which type of skin cancer is most likely to metastasize rapidly and requires early detection for successful treatment?

Accepted Answer

Malignant melanoma

Question 20

Which formula best represents the effect of melanin on UV protection and risk of skin cancer?

Accepted Answer

$	ext{Melanin} \uparrow ightarrow 	ext{UV protection} \uparrow ightarrow 	ext{Skin cancer risk} \downarrow$

The Integumentary System: Structure, Function, and Clinical Relevance

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