NURS 207 Skin Quiz - Tortora Ch. 5

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Questions and Answers

What is the initial precursor for the synthesis of the biologically inactive form of vitamin D?

Cholesterol found in the skin (correct)

Keratin produced in the epidermis

Melanin produced in the dermis

Vitamin D3 from dietary sources

Which phase is NOT part of deep wound healing?

Migratory phase

Inflammatory phase

Proliferative phase

Epidermal phase (correct)

What triggers the stop of growth and migration of basal cells during epidermal wound healing?

Contact inhibition (correct)

Scarring of the dermis

Increased oxygen supply

Nutrient depletion

What is a characteristic of deep wound healing compared to epidermal wound healing?

It can lead to scar tissue formation Signup and view all the answers

What role do topical steroids play in relation to the skin?

They promote epidermal wound healing Signup and view all the answers

Which statement about skin structure is FALSE?

There are more sudoriferous glands in thick than thin skin Signup and view all the answers

Which of the following is NOT a function of skin?

Production of keratin to protect UV damage Signup and view all the answers

Which process does NOT occur during epidermal wound healing?

Dermal layers contribute to the central portion of the wound Signup and view all the answers

During deep wound healing, which statement is NOT accurate?

Angiogenesis occurs only in the inflammatory phase Signup and view all the answers

Which of the following describes a common misconception about skin?

Sebaceous glands are absent in thick skin Signup and view all the answers

What is the primary function of the tight junctions in epithelial cells?

To limit movement of substances between cells Signup and view all the answers

Which layer of the epidermis contains flattened dead keratinocytes?

Stratum corneum Signup and view all the answers

Which membrane of the transporting epithelial cell faces the extracellular fluid (ECF)?

Basolateral membrane Signup and view all the answers

What is a primary function of the stratum lucidum?

To serve as a barrier in thick skin Signup and view all the answers

Paracellular transport primarily involves movement through which of the following?

Tight junctions between adjacent cells Signup and view all the answers

Which characteristic is true of thick skin compared to thin skin?

Thick skin contains the stratum lucidum. Signup and view all the answers

What term is used to describe the transport of substances from the lumen to the extracellular fluid?

Absorption Signup and view all the answers

How does the skin contribute to thermoregulation?

Through the dilatation or constriction of blood vessels Signup and view all the answers

Which structure in the epithelial cells is specialized for absorption?

Microvilli on the apical membrane Signup and view all the answers

What type of transport involves proteins that direct movement across the epithelium?

Directional transport Signup and view all the answers

Which type of skin is generally hairless?

Thick skin Signup and view all the answers

What is the main role of microvilli on the epithelial cells?

Increasing surface area for absorption Signup and view all the answers

What function does keratin perform in the skin?

It protects underlying tissues. Signup and view all the answers

Which of the following has fewer glandular structures?

Thin skin Signup and view all the answers

Which of the following transport processes is categorized as transcellular absorption?

Transport through transport proteins Signup and view all the answers

What structure in the skin is involved in the immune response?

Intraepidermal macrophages Signup and view all the answers

What is the process by which transcellular transport occurs?

Transcytosis involving endocytosis and exocytosis Signup and view all the answers

During transcytosis, what role do caveolae play?

They concentrate plasma proteins during endocytosis. Signup and view all the answers

Which of the following describes the role of carrier proteins in transcellular transport?

They facilitate movement through cell membranes. Signup and view all the answers

Which mechanism is primarily responsible for the transport of macromolecules across cell membranes?

Transcytosis Signup and view all the answers

What component of the cell is crucial for vesicular transport during transcytosis?

Cytoskeleton Signup and view all the answers

Which fluid is primarily involved in the transcellular transport process in capillaries?

Interstitial fluid Signup and view all the answers

What happens to vesicles after they cross the cell during transcytosis?

They fuse with the plasma membrane and release their contents. Signup and view all the answers

Which membranes are involved in transcellular transport?

Both apical and basolateral membranes Signup and view all the answers

What role do neutrophils and monocytes (macrophages) play in the inflammatory phase of wound healing?

They phagocytize microbes and dead tissues. Signup and view all the answers

What is the primary function of fibroblasts during the migratory phase of deep wound healing?

To lay down collagen fibers and glycoproteins. Signup and view all the answers

Which of the following occurs during the proliferative phase of deep wound healing?

Epithelial cells grow extensively beneath the scab. Signup and view all the answers

What marks the onset of the maturation phase in wound healing?

Degradation of the scab. Signup and view all the answers

Which statement about epithelial transport is correct?

It involves moving substances across the apical and basolateral membranes. Signup and view all the answers

What is the typical time frame for fibroblast proliferation to peak after a wound occurs?

1 to 2 weeks Signup and view all the answers

Which of the following defines the apical membrane in epithelial tissue?

Surface that faces the lumen of an organ. Signup and view all the answers

During which phase of wound healing does angiogenesis primarily occur?

Migratory phase Signup and view all the answers

What typically corresponds with the healing of the epidermis during the maturation phase?

Decreased fibroblast activity Signup and view all the answers

What is a characteristic of the inflammatory phase of wound healing?

It includes steps like vasodilation and phagocyte emigration. Signup and view all the answers

Study Notes

Skin (Cutaneous Membrane)

Skin type, function, wound healing, and epithelial transport are covered in NURS 207(N01)
Reading material is Tortora, 16th ed., Ch. 5 (October 7, 2024)

Objectives

Compare the structural and functional differences between thin and thick skin
List the physiological functions of skin
Describe how the integumentary system contributes to homeostasis
Explain how epidermal and deep wounds heal
Describe epithelial transport mechanisms, including transportation between compartments within the body across a layer of epithelial cells

Review: 5 Layers in a Typical Epidermis

Stratum corneum: Layers of flattened, dead keratinocytes; absence of nuclei and internal organelles
Stratum lucidum: Primarily in thick skin (fingertips, palms, soles); flattened keratinocytes undergoing apoptosis
Stratum granulosum: Flattened keratinocytes undergoing apoptosis
Stratum spinosum: Cells appear with thorn-like spines
Stratum basale: Deepest layer of the epidermis

Structural and Functional Differences in Thin and Thick Skin

Thin skin: Covers most of the body; thickness 0.10–0.15 mm; hairy; fewer sebaceous and sudoriferous glands; fewer sensory receptors
Thick skin: Found on palms, soles, and fingertips; thickness 0.6–4.5 mm; hairless; fewer sebaceous and sudoriferous glands; more sensory receptors

Functions of Skin (Homeostasis)

Thermoregulation: Skin regulates body temperature through blood vessel dilation or constriction.
Body protection: Keratin protects underlying tissues from damage; lamellar granules reduce evaporation and contain bactericidal chemicals; melanin protects from UV damage and intraepidermal macrophages play a role in immune system.
Cutaneous sensations: Skin provides sensory information (pleasure, pain, texture, etc.)
Vitamin D production: Skin produces a precursor to vitamin D, which is activated by UV-B light and converted to its active form in the kidneys.
Excretion: Skin excretes water, salts, ammonia, and urea
Absorption: Skin absorbs topical steroids

Epidermal Wounds and Deep Wounds Healing

Epidermal wound healing: Typically involves superficial injury of the epidermal layer; basal cells divide, detach, enlarge and migrate to close the wound.
Deep wound healing: Trauma extending to the dermis and subcutaneous layer; involves multiple phases:
Inflammatory phase: Blood clot adheres to wound edges; initiating inflammation to eliminate microbes, foreign substances, and dead tissues. Has three stages: vasodilation and increased permeability; phagocyte emigration; tissue repair
Migratory phase: Clot becomes a scab; fibroblasts migrate to the injury site; starts producing structural molecules (scar tissue) and collagen fibers; angiogenesis begins.
Proliferative phase: Extensive growth of epithelial cells beneath the scab; angiogenesis and fibroblast proliferation occur simultaneously; fibroblast proliferation peaks 1-2 weeks and ends at 2-4 weeks post-wounding; fibroblasts form collagen matrix and strengthen the wound.
Maturation phase: Scab degrades; epidermis thickness returns to normal; collagen fibers become organized; fibroblast population decreases; blood circulation returns to normal

Epithelial Transport

Epithelium lines cavities, organs, and surface structures.
Transport involves moving substances across two membranes:
Apical membrane: Faces the lumen
Basolateral membrane: Faces the extracellular fluid
Different transport proteins: allow for directional transport across epithelium.
Transport from lumen to extracellular fluid (ECF) is absorption; ECF to lumen is secretion.
Two types of epithelial transport:
Paracellular: Through junctions between adjacent cells.
Transcellular: Involves transport through the cell using endocytosis, vesicular transport, cytoplasm, exocytosis through apical and basolateral membranes via carrier proteins.
Transcytosis: Combination of endocytosis, vesicular transport across the cytoplasmic space, and exocytosis. Allows for transport of macromolecules or large molecules across apical-basolateral membranes.

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Description

Test your knowledge on the skin, its types, functions, and wound healing based on NURS 207 materials. This quiz focuses on the integumentary system's role in homeostasis, the structure of the epidermis, and epithelial transport mechanisms. Challenge yourself and reinforce your understanding of these essential topics!