Epidermis Structure and Functions Quiz

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Questions and Answers

Which layer of the epidermis is primarily responsible for the production of the horny layer?

Stratum basale

Stratum corneum (correct)

Stratum lucidum

Stratum granulosum

What type of cells are primarily found in the stratum spinosum of the epidermis?

Columnar cells

Flattened cells

Cuboidal cells

Polyhedral cells (correct)

What condition is characterized by the loss of cohesion between epidermal cells, resulting in intraepidermal clefts?

Microvesiculation

Intracellular oedema

Acantholysis (correct)

Hydropic degeneration

In which layer of the epidermis would you find nucleated, flattened keratinocytes?

Stratum granulosum Signup and view all the answers

What type of degeneration is specifically associated with viral infections?

Ballooning degeneration Signup and view all the answers

Which type of hair follicle is typical for cattle and horses?

Simple hair follicles Signup and view all the answers

Which term describes the migration of inflammatory cells or erythrocytes through intercellular spaces of the epidermis?

Exocytosis Signup and view all the answers

What are the characteristics of the stratum lucidum?

Thin band of flattened, unstained cells Signup and view all the answers

Which form of cellular change is associated with an increase in cell size and cytoplasmic pallor?

Intracellular oedema Signup and view all the answers

What type of cells contribute to the pigmentation of the epidermis?

Melanocytes Signup and view all the answers

What is the appearance of clefts (lacunae) within the epidermis?

Slit-like spaces without fluid Signup and view all the answers

In hair follicles, what is the role of the dermal papilla?

Provides nutrients to the hair growth Signup and view all the answers

What can cause microvesicles and vesicles in the epidermis?

Both A and C Signup and view all the answers

Which of the following layers of the skin undergoes active mitosis?

Stratum basale Signup and view all the answers

Hydropic degeneration is most commonly associated with which condition?

Lupus erythematosus Signup and view all the answers

Which of these describes a condition resulting from a severe inflammatory response, commonly leading to vesicle formation?

Spongiosis Signup and view all the answers

What condition is suggested by diffuse orthokeratotic hyperkeratosis?

Nutritional deficiencies Signup and view all the answers

What does hypergranulosis indicate regarding the stratum granulosum?

Increased thickness Signup and view all the answers

Which of the following describes dyskeratosis?

Premature keratinization of viable cells Signup and view all the answers

Acanthosis specifically indicates an increase in the thickness of which epidermal layer?

Stratum spinosum Signup and view all the answers

What is a characteristic feature of necrolysis?

Death of cells or tissues Signup and view all the answers

What does hypokeratosis indicate about the stratum corneum?

Decrease in thickness Signup and view all the answers

Which condition is associated with epidermal atrophy?

Hyperadrenocorticism Signup and view all the answers

What cellular changes occur during necrosis?

Karyolysis and necrolysis Signup and view all the answers

What is characterized by excess melanin deposited within the epidermis?

Hyperpigmentation Signup and view all the answers

Which condition is characterized by a decrease in melanin within the epidermis?

Vitiligo Signup and view all the answers

What type of cyst is characterized by flattened epidermal cells and lamellar keratin?

Horn cysts Signup and view all the answers

What condition involves circular concentric layers of squamous cells that show gradual keratinization?

Horn pearls Signup and view all the answers

What describes a consolidated, desiccated surface mass composed of serum, keratin, and cellular debris?

Crust Signup and view all the answers

What is a feature of chronic inflammation observed in dermal changes?

Collagen hyalinization Signup and view all the answers

Which term describes cavities filled with inflammatory cells within the epidermis?

Microabscesses Signup and view all the answers

What type of degeneration resembles fibrin and is associated with connective tissue disease?

Fibrinoid degeneration Signup and view all the answers

What type of tissue formation is characterized by an increase in fibrous tissue?

Fibroplasia Signup and view all the answers

What is a characteristic feature of exuberant granulation tissue?

Vertically oriented capillaries and horizontally oriented fibroblasts Signup and view all the answers

Which condition is associated with an irregular undulating configuration of the epidermis?

Papillomatosis Signup and view all the answers

What does pigmentary incontinence indicate?

Presence of free melanin granules within the dermis Signup and view all the answers

What signifies mucinous degeneration in derma changes?

Thinning of dermal collagen fibrils Signup and view all the answers

Which change occurs in the subcutaneous layer of the skin?

Granulomatous dermatoses Signup and view all the answers

What type of inflammation can occur in sebaceous and apocrine sweat glands?

Suppurative and granulomatous inflammation Signup and view all the answers

What is a common feature of dermatitis related to vascular changes?

Hyalinization of endothelial cells Signup and view all the answers

What is the primary function of the integumentary system in terms of protection?

Prevents the loss of water and electrolytes Signup and view all the answers

Which of the following components is NOT part of the skin structure?

Hepatitis Signup and view all the answers

Which function of the integumentary system involves thermoregulation?

Evaporation of excess heat through sweat Signup and view all the answers

What role does subcutaneous adipose tissue play in the integumentary system?

Acts as a major energy storage Signup and view all the answers

How does skin pigmentation benefit animals?

Prevents damage from solar radiation Signup and view all the answers

What is a significant economic impact of skin diseases in food-producing animals?

Triggering systemic diseases Signup and view all the answers

Which of the following skin functions relates closely to sensation?

Contains receptors for touch and temperature Signup and view all the answers

Which aspect of the integumentary system is involved in motion, shape, and color?

Flexibility and elasticity of the skin Signup and view all the answers

Study Notes

Integumentary System - Veterinary Pathology

The integumentary system is the largest body system, forming a boundary between the animal and its external environment.
Skin diseases are common in veterinary practice and can indicate systemic issues, leading to economic losses in livestock.
Skin functions include:
- Protection: Provides a barrier against UV light, mechanical, chemical, and thermal insults, preventing water and electrolyte loss and microbial invasion.
- Sensation: Holds receptors for touch, pressure, pain, and temperature.
- Thermoregulation: Hairs and subcutaneous adipose tissue regulate heat loss.
- Metabolic: Subcutaneous adipose tissue is a significant energy store (triglycerides), and the epidermis synthesizes Vitamin D.
- Motion, Shape, and Colour: Skin's flexibility, elasticity, and toughness contribute to movement, shape, and colour determined through melanin formation, vascularity and keratinization, to protect against solar damage.
- Indicator: Skin conditions can be an indicator of underlying systemic issues.

Skin Structure

Composition: Epidermis, dermis, hair follicles, adnexal glands, and subcutis (hypodermis).
Diagram: There are illustrations of the layers of skin and the components within, including blood vessels. Diagrams show both macroscopic and microscopic views.
Epidermis layers: Stratum basale (basal layer), stratum spinosum (prickle layer), stratum granulosum (granular layer), stratum lucidum (clear layer), and stratum corneum (horny layer).
Dermis Layers: Papillary layer and reticular layer. The reticular layer contains more dense connective tissue.
Hypodermis (Subcutis): Is the deepest layer, with connective tissue, fat, blood vessels & nerves, and acts as a heat insulator and is crucial for body contour.

Epidermal Appendages (Adnexa)

Hair follicles:
- Types: Simple (cattle, horses) and compound (sheep, dogs).
- Cycles: Anagen (active growth), catagen (transitional), and telogen (resting).
- Structure: Composed of follicle, sebaceous gland, arrector pili muscle, and apocrine sweat glands.
Glands:
- Sebaceous glands: Holocrine glands, producing sebum (triglyceride/cholesterol) which are part of the hair follicle complex.
- Apocrine sweat glands: In hoofed animals; develop as part of the hair follicle complex.
- Eccrine sweat glands: Open directly to the epidermis: produce water and salt, present on paws and pads.

Dermis (Corium)

Function: Support, nourish, and maintain the epidermis and its appendages. Composed of collagen, reticulin (immature collagen), and elastin fibers. Contains fibroblasts, inflammatory cells (lymphocytes, macrophages) and a glycosaminoglycan-rich ground substance . There is a difference between the fibrous texture of the superficial and deep dermis.
Changes: Exuberant granulation tissue, formation of fibrous tissue (fibroplasia, fibrosis, sclerosis); collagen and fibroblast involvement. Papillomatosis also includes projection of dermal papillae resulting in an irregularly undulating epidermis. There can be an increased presence of melanin that is free within the subepidermal dermis and within dermal macrophages (melanophages), termed pigmentation incontinence. Dermal oedema refers to dilated lymphatics and widened perivascular and interstitial spaces, often caused by mucinous degeneration.

Subcutaneous Changes

Fat: Suppurative and granulomatous changes (like panniculitis and steatitis) and necrosis.

Epidermal Changes - Detailed

Hyperkeratosis: Increased stratum corneum thickness; can be absolute (actual increase) or relative (apparent increase due to thinning of the underlying epidermis). Further identified as orthokeratotic (anuclear) or parakeratotic (nucleated). Commonly associated with chronic irritation, inflammation or sun exposure.
Hypokeratosis: Reduced stratum corneum thickness. Often associated with chronic infections, rapid turnover, or topical treatments.
Dyskeratosis: Premature and faulty keratinization of the viable cells of the stratum spinosum; characterized by shrunken cells, separation from adjacent keratinocytes, pyknotic nuclei, and bright eosinophilic cytoplasm.
Hyperplasia/Acanthosis: Increase in the thickness of the non-cornified epidermis, typically caused by increased number of epidermal cells. Specifically involves the stratum spinosum.
Hypoplasia/atrophy: Decrease in epidermal thickness; results from decreased cell number (hypoplasia) or decreased cell size (atrophy).
Necrosis/Necrolysis: Cell death.
Intercellular oedema (spongiosis): Widening intercellular bridges of the epidermis; associated with acute or subacute dermatoses..
Intracellular oedema: Increased cell size and cytoplasmic pallor; possible artifacts. Can include Ballooning degeneration often associated with viral infections and Hydrophic degeneration common with lupus and drug reactions.
Acantholysis: Loss of cohesion between epidermal cells leading to clefts, vesicles, and bullae.
Exocytosis: Inflammatory cells and/or erythrocytes migrating through intercellular spaces.
Clefts (lacunae): Slit-like spaces that do not contain fluid, often due to acantholysis or hydropic degeneration of the basal cells.
Microvesicles, vesicles, bullae: Relatively a cellular spaces within or below the epidermis, potentially due to ballooning degeneration, acantholysis, subepidermal oedema, and intracellular/intercellular oedema..
Microabscesses, pustules: Macroscopic or microscopic lesions, intraepidermal or subepidermal, filled with inflammatory cells.
Hyperpigmentation/hypermelanosis: Excess melanin deposition within the epidermis and dermal melanophages.
Hypoigmentation/hypomelanosis Reduced melanin deposition within the epidermis and dermal melanophages.
Crusts: Consolidated, desiccated surface masses composed of keratin, serum, cellular debris, and often microorganisms.
Horn cysts (keratin cysts): Circular cysts surrounded by flattened epidermal cells, containing concentrically arranged lamellar keratin.
Horn pearls (squamous pearls): Focal, circular structures of concentric layers of squamous cells, undergoing gradual keratinization toward the center. Often accompanied by dyskeratosis.

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Description

Test your knowledge about the various layers of the epidermis, their functions, and associated conditions. This quiz covers topics such as keratinocytes, hair follicles, and the types of cells found in the epidermis, ensuring a comprehensive understanding of skin biology.