Deck 18: Skin

Question 1

Which of the following components of the epidermis provides sealant between adjacent cells?

A) Keratohyaline granules
B) Glycolipids and lipids
C) Keratin
D) Desmosomes
E) Adherent junctions

Answer 1

Glycolipids and lipids

Question 2

Which cells derive from precursors originating in the bone marrow and function as antigen-presenting cells in skin?

A) Keratinocytes
B) Langerhans cells
C) Melanocytes
D) Merkel cell
E) Arrector pili

Answer 2

Langerhans cells

Question 3

Cells responsible for producing the pigment for dark hair are located in which of following?

A) The cortex of the hair shaft
B) Throughout the hair shaft
C) The internal root sheath of the hair
D) The dermal papilla of the hair bulb
E) The hair matrix (zone of dividing and differentiating cells) of the hair bulb

Answer 3

The hair matrix (zone of dividing and differentiating cells) of the hair bulb

Question 4

Which of the following separates the hair follicle from the connective tissue of the dermis?

A) External root sheath
B) Internal root sheath
C) Glassy membrane
D) Hair cuticle
E) Medulla

Question 5

Which structure typifies reticular dermis but not papillary dermis?

A) Capillaries
B) Dense irregular connective tissue
C) Meissner tactile corpuscles
D) Sweat gland ducts
E) Type I collagen fibers

Question 6

Which of the following best characterizes sebaceous glands?

A) Its duct drains onto the skin surface.
B) It releases its contents via holocrine secretion.
C) It primarily secretes water and salts.
D) Its secretory units are supplied by adrenergic stimulation.
E) It is located typically in the reticular dermis.

Question 7

Myoepithelial cells aid in the secretory process of which of the following?

A) Melanocytes
B) Sebaceous glands
C) Keratinocytes of the granular layer
D) Eccrine sweat glands
E) Apocrine sweat glands

Question 8

A 52-year-old woman presents with severe blistering over her buttocks. Analysis of her serum demonstrates the presence of antibodies which by imunohistochemical techniques stain material located at the basement membrane of the epidermis in a biopsy of her skin. The underlying biological mechanism of her skin disorder involves an abnormality in which of the following structures?

A) Macula adherens
B) Gap junctions
C) Hemidesmosomes
D) Zonula occludens (tight junctions)
E) Zonula adherens

Question 9

A 64-year-old woman, who has always been proud of her suntanned, healthy look, is referred to a dermatologist with a blue-violet, painless, 1.5 -cm lump in the skin of her left shoulder. The lump is firm and cannot be moved, and has grown very rapidly over the past few weeks. The mass is removed surgically and the pathologist diagnoses it as a Merkel cell carcinoma. If the UV radiation to which her skin was exposed affected the Merkel cells, what other cell type sharing the same specific epidermal layer might also be affected?

A) Fibroblasts of the papillary layer
B) Keratinocytes of the stratum granulosum
C) Cells of tactile (Meissner) corpuscles
D) Keratinized epithelial cells
E) Basal stem cells for keratinocytes

Question 10

A 37-year-old woman presents with a suspected Schwannoma. The radiology report indicates "a soft tissue mass to the right of L1 at the level of the L1 to L2 neural foramen." The neurologist presses the base of a vibrating $128 \mathrm{cps}$ tuning fork to the skin of the patient's right and left thighs and asks her to describe the sensation. She asks the patient to close her eyes and then to tell her whether the tuning fork is vibrating or not. With that instrument the doctor is primarily testing the function of which of the following sensory receptors?

A) Lamellated (Pacinian) corpuscles
B) Kraus end bulbs
C) Meissner corpuscles
D) Merkel cells
E) Free nerve endings