Question 1

Which layer of the epidermis is primarily responsible for the generation of new keratinocytes, and what is its main function?

Accepted Answer

Stratum basale; contains stem cells that divide to replace superficial keratinocytes

Question 2

A patient presents with a bluish coloration of the lips and nail beds after exposure to extreme cold. What is the most likely physiological explanation for this change in skin color?

Accepted Answer

Sustained reduction in blood supply leading to decreased oxygenation of hemoglobin

Question 3

Which of the following best describes the role of the papillary layer of the dermis?

Accepted Answer

Contains capillaries, lymphatic vessels, and sensory nerve fibers that supply the surface of the skin

Question 4

Which protein is the basic structural component of hair and nails, and what is its primary function?

Accepted Answer

Keratin; forms a tough, fibrous barrier for protection

Question 5

A deep laceration on the forearm destroys the epidermis and part of the deep dermis. Will hair regrow in the affected area after healing, and why?

Accepted Answer

No, because the destruction of the deep dermis eliminates the hair follicles

Question 6

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 7

What is the main function of the arrector pili muscle in the integumentary system?

Accepted Answer

Contracts to produce goosebumps and elevate hair

Question 8

Which of the following best explains the process by which exposure to sunlight increases vitamin D$$_3$$ production in the skin?

Accepted Answer

Ultraviolet radiation converts cholesterol derivatives in the epidermis to vitamin D$$_3$$

Question 9

Which type of gland is most affected by hormonal changes at puberty and is responsible for body odor?

Accepted Answer

Apocrine sweat gland

Question 10

A patient with Addison's disease presents with darkening of the skin. What is the underlying cause of this pigmentation change?

Accepted Answer

Increased secretion of adrenocorticotropic hormone (ACTH) stimulating melanocytes

Question 11

Which of the following is a function of subcutaneous fat in the hypodermis?

Accepted Answer

Serves as an energy reserve and shock absorber

Question 12

Which of the following best describes the difference between insensible and sensible perspiration?

Accepted Answer

Insensible perspiration is evaporative water loss by diffusion across the skin; sensible is water loss due to sweat gland secretion

Question 13

Which cell type in the stratum spinosum is responsible for immune defense against pathogens and superficial skin cancer?

Accepted Answer

Dendritic (Langerhans) cells

Question 14

A patient with jaundice presents with yellowing of the skin and eyes. What is the physiological basis for this condition?

Accepted Answer

Accumulation of bilirubin in body fluids due to liver dysfunction

Question 15

Which of the following best explains why incisions made parallel to tension (cleavage) lines in the skin heal better than those made perpendicular?

Accepted Answer

Parallel incisions remain closed and heal with less scarring due to alignment with collagen and elastic fiber bundles

Question 16

Which of the following is a direct effect of aging on the integumentary system?

Accepted Answer

Decreased basal cell activity and reduced vitamin D$$_3$$ production

Question 17

Which pigment is most responsible for the yellow-orange coloration of the skin, and where is it most apparent?

Accepted Answer

Carotene; in the stratum corneum of light-skinned individuals

Question 18

Which of the following best describes the function of keratohyalin in the stratum granulosum?

Accepted Answer

Initiates aggregation and cross-linking of keratin fibers, leading to cell dehydration

Question 19

Which of the following equations best represents the relationship between vitamin D$$_3$$ synthesis and sunlight exposure in the skin?

Accepted Answer

$$ 7	ext{-dehydrocholesterol} + UVB ightarrow 	ext{cholecalciferol (vitamin D}_3	ext{)} $$

Chapter 5: The Integumentary System – Structure and Function

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