A&P 1 101 MODULE 7 EXAM INTEGUMENTARY SYSTEM
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[Section 1: Layers of the Skin & Histology (Q1-14)]
Q1. A histology slide of thick skin from the palm shows five distinct epidermal strata.
A student observes a clear, translucent layer located between the stratum
granulosum and the stratum corneum. Which layer is described, and what is its
primary histological composition?
A. Stratum basale; composed of mitotically active cuboidal cells B. Stratum spinosum;
composed of polyhedral cells with desmosomes C. Stratum lucidum; composed of
eleidin, a clear protein derived from keratohyalin [CORRECT] D. Stratum corneum;
composed of 15-30 layers of dead keratinocytes
Rationale: The stratum lucidum is found only in thick skin (palms, soles, digits) and is
characterized by its translucent appearance due to eleidin, a transformation product
of keratohyalin. Students often confuse this with the stratum corneum because both
contain dead cells, but the lucidum's clear, glassy appearance distinguishes it
microscopically.
Correct Answer: C
Q2. During a microscopic examination of thin skin, a pathologist identifies dendritic
cells interspersed among keratinocytes in the stratum spinosum. These cells contain
Birbeck granules and function as antigen-presenting immune defenders. Which cell
type is being described?
A. Merkel cells B. Melanocytes C. Langerhans cells [CORRECT] D. Basal cells
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Rationale: Langerhans cells are dendritic cells derived from CD34-positive bone
marrow stem cells that reside primarily in the stratum spinosum. They express MHC I
and II molecules and function in antigen presentation. A common misconception is
confusing these with Merkel cells (mechanoreceptors) or melanocytes (pigment
producers).
Correct Answer: C
Q3. A nursing student is reviewing the dermal layers and notes that the superficial
layer projects finger-like projections into the stratum basale of the epidermis. These
projections increase the surface area for nutrient exchange and contain tactile
(Meissner) corpuscles. Which layer and structure are being described?
A. Reticular layer; dermal ridges B. Papillary layer; dermal papillae [CORRECT] C.
Hypodermis; adipose lobules D. Stratum spinosum; desmosomes
Rationale: The papillary layer of the dermis is composed of loose areolar connective
tissue and forms dermal papillae that interdigitate with the epidermal ridges. These
papillae contain capillary loops and tactile corpuscles. The reticular layer is deeper
and composed of dense irregular connective tissue; students often confuse the two
layers' locations and functions.
Correct Answer: B
Q4. A histology instructor points to a micrograph showing the deepest epidermal
layer attached to the basal lamina via hemidesmosomes. This layer contains cuboidal
stem cells that undergo continuous mitosis, as well as melanocytes and Merkel cells.
Which stratum is being identified?
A. Stratum corneum B. Stratum granulosum C. Stratum spinosum D. Stratum basale
[CORRECT]
Rationale: The stratum basale (stratum germinativum) is the single deepest layer of
the epidermis where all keratinocytes originate through mitotic division. It is the only
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layer attached to the basement membrane and contains melanocytes and Merkel
cells. Students sometimes mistakenly identify this as the stratum spinosum because
both contain living cells.
Correct Answer: D
Q5. In a clinical scenario, a patient presents with decreased skin elasticity and poor
wound healing. The physician explains that the deeper dermal layer responsible for
tensile strength and structural integrity has been compromised. This layer contains
dense irregular connective tissue with collagen and elastin fibers. Which layer is
affected?
A. Papillary layer B. Reticular layer [CORRECT] C. Stratum corneum D. Hypodermis
Rationale: The reticular layer constitutes approximately 80% of the dermis and is
composed of dense irregular connective tissue with collagen (provides tensile
strength) and elastin (provides elasticity) fibers. The papillary layer is superficial and
loose; the hypodermis is subcutaneous fat, not technically part of the skin.
Correct Answer: B
Q6. A dermatologist examines a biopsy and notes that the keratinocytes in the
stratum granulosum contain dark-staining granules of keratohyalin and are
beginning to undergo apoptosis. These cells are also secreting glycolipids via
lamellar bodies to form a water barrier. Which process is primarily occurring in this
stratum?
A. Desquamation of dead cells B. Keratinization and formation of the epidermal water
barrier [CORRECT] C. Melanin transfer to keratinocytes D. Cell division and
proliferation
Rationale: The stratum granulosum is where keratinocytes accumulate keratohyalin
granules and release lamellar body contents (glycolipids) to form the waterproof
barrier. Nuclei begin to disintegrate here. Students often confuse this with the