Q: Which of the following equations best represents the relationship between the rate of diffusion ($$D$$), surface area ($$A$$), concentration gradient ($$\Delta C$$), and thickness of the membrane ($$d) in $$the context of nutrient diffusion to the epidermis?

$$D = \frac{A \times \Delta C}{d}$$

Question 1

A patient presents with a third-degree burn on their forearm. Which of the following best describes the extent of tissue damage in a third-degree burn?

Accepted Answer

It destroys the epidermis and dermis, potentially damaging underlying tissues such as subcutaneous fat, nerves, and blood vessels.

Question 2

Which of the following statements about the epidermis is correct?

Accepted Answer

The epidermis is composed of keratinized stratified squamous epithelium and is avascular.

Question 3

A topical medication is designed to be absorbed through the skin without entering the bloodstream. Which property should this medication have to maximize its effectiveness and safety?

Accepted Answer

It should be nonpolar, allowing it to cross the lipid-rich stratum corneum but not enter systemic circulation.

Question 4

Which layer of the epidermis is responsible for the continuous production of new keratinocytes through mitosis?

Accepted Answer

Stratum basale

Question 5

A person with a genetic mutation that prevents the production of melanin would be most at risk for which of the following?

Accepted Answer

Increased risk of UV-induced DNA damage and skin cancer

Question 6

Which of the following best explains why the epidermis is limited in thickness?

Accepted Answer

The epidermis is limited by the need for diffusion of oxygen and nutrients from the dermis, as it is avascular.

Question 7

A needle is inserted into the epidermis of thin skin. In which order does the needle pass through the layers, from superficial to deep?

Accepted Answer

Stratum corneum, stratum granulosum, stratum spinosum, stratum basale

Question 8

Which of the following is a function of the dermal papillae?

Accepted Answer

They interlock with the epidermis, increasing the surface area for exchange of gases, nutrients, and waste products.

Question 9

Which of the following best describes the role of sweat glands in thermoregulation?

Accepted Answer

They release sweat, which evaporates and cools the body when body temperature rises.

Question 10

A patient has a mutation affecting the desmosomes in their epidermis. Which of the following symptoms would you most likely expect?

Accepted Answer

Fragile skin that blisters easily due to poor cell-to-cell adhesion

Question 11

Which of the following equations best represents the relationship between the rate of diffusion ($$D$$), surface area ($$A$$), concentration gradient ($$\Delta C$$), and thickness of the membrane ($$d) in $$the context of nutrient diffusion to the epidermis?

Accepted Answer

$$D = \frac{A 	imes \Delta C}{d}$$

Question 12

Which of the following best explains why thick skin is found on the palms and soles?

Accepted Answer

These areas are subject to high mechanical stress and require additional layers for protection.

Question 13

Which of the following is NOT a function of the integumentary system?

Accepted Answer

Production of red blood cells

Question 14

A person with jaundice has yellowing of the skin. Which pigment is most likely responsible for this change in skin color?

Accepted Answer

Bilirubin

Question 15

Which of the following best describes the process of keratinocyte movement through the epidermis?

Accepted Answer

Keratinocytes originate in the stratum basale, undergo mitosis, and are pushed upward through the layers until they are shed from the stratum corneum.

Question 16

Which of the following best explains why the stratum corneum is an effective barrier to water loss?

Accepted Answer

It is composed of dead keratinocytes filled with keratin and coated with a lipid-based substance.

Question 17

Which of the following best describes the function of Langerhans (dendritic) cells in the epidermis?

Accepted Answer

They act as immune cells, protecting the skin from pathogens.

Question 18

A patient is unable to produce sweat due to a genetic disorder. Which of the following physiological processes would be most directly impaired?

Accepted Answer

Thermoregulation

Question 19

Which of the following best describes the role of vitamin D synthesis in the skin?

Accepted Answer

UV radiation converts a cholesterol-like compound in the skin to cholecalciferol (vitamin D3), which is then modified by the liver and kidneys to form calcitriol.

The Integumentary System: Structure, Function, and Clinical Relevance

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