Integumentary System Quiz

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Questions and Answers

What is primarily produced by the epidermis?

Sebum

Horny layer (correct)

Hair

Melanin

Which layer of the epidermis is described as the 'prickle layer'?

Stratum lucidum

Stratum granulosum

Stratum corneum

Stratum spinosum (correct)

In which layer of the epidermis do cells begin to flat and lose their nuclei?

Stratum lucidum

Stratum granulosum (correct)

Stratum corneum

Stratum basale

What type of cells are found in the stratum basale of the epidermis?

Cuboidal or columnar cells Signup and view all the answers

Which of the following is NOT a function of the epidermis?

Support blood vessels Signup and view all the answers

What is the primary type of cell in the stratum corneum?

Dead, fully keratinized cells Signup and view all the answers

Which type of hair follicle is characterized as 'compound'?

Sheep, goats, dogs, and cats Signup and view all the answers

What structures are part of the hair follicle?

Root sheaths and dermal papilla Signup and view all the answers

What is one of the primary functions of the integumentary system?

Thermoregulation by insulating the body Signup and view all the answers

Which of the following structures is NOT part of the skin?

Heart Signup and view all the answers

How does skin pigmentation benefit the animal?

Prevents damage from solar radiation Signup and view all the answers

What metabolic function does the subcutaneous adipose tissue serve?

Storage of triglycerides for energy Signup and view all the answers

Which type of sensory receptors are found in the skin?

Receptors for touch and temperature Signup and view all the answers

What is a significant role of the epidermis in the integumentary system?

Synthesis of Vitamin D Signup and view all the answers

Which of the following conditions can skin diseases indicate?

Systemic diseases Signup and view all the answers

What anatomical boundary does the integumentary system form?

Between the animal and its external environment Signup and view all the answers

What are the classifications of hyperkeratosis?

Anuclear and nucleated Signup and view all the answers

Which layer of skin is primarily associated with the presence of lymphatics?

Superficial dermis Signup and view all the answers

What does diffuse parakeratotic hyperkeratosis most consistently indicate?

Zinc responsive dermatoses Signup and view all the answers

Which description accurately differentiates thin skin from thick skin?

Thick skin has a thicker epidermis. Signup and view all the answers

Which type of receptors corresponds to the sensation of deep pressure?

Mechanoreceptors Signup and view all the answers

Chronic stimuli such as trauma or inflammation can lead to which epidermal change?

Hyperkeratosis Signup and view all the answers

What is the characteristic feature of parakeratotic hyperkeratosis?

Presence of nucleated cells Signup and view all the answers

What type of change does dermatohistopathology primarily focus on?

Dermal changes Signup and view all the answers

What are microabscesses and pustules filled with?

Inflammatory cells Signup and view all the answers

Which condition is associated with hyperpigmentation?

Chronic inflammatory dermatoses Signup and view all the answers

What characterizes a crust?

A consolidated surface mass of keratin and debris Signup and view all the answers

What is a horn cyst primarily composed of?

Epidermal cells and keratin Signup and view all the answers

What type of changes are associated with fibrinoid degeneration?

Brightly eosinophilic fibrillar substances Signup and view all the answers

What is a hallmark of horn pearls?

Concentric layers of keratinized squamous cells Signup and view all the answers

Hypopigmentation is primarily characterized by what?

Reduction of melanin in the epidermis Signup and view all the answers

What is typically seen in the dermal changes associated with chronic inflammation?

Dystrophic mineralization Signup and view all the answers

What does diffuse orthokeratotic hyperkeratosis primarily suggest?

Nutritional deficiencies Signup and view all the answers

What characterizes hypokeratosis?

Decreased thickness of the stratum corneum Signup and view all the answers

Which of the following conditions is indicative of dyskeratosis?

Faulty keratinization with pyknotic nuclei Signup and view all the answers

Hypergranulosis is characterized by what change in the stratum granulosum?

Increased thickness Signup and view all the answers

What does acanthosis specifically refer to in epidermal changes?

Increase in cell number in the epidermis Signup and view all the answers

What is necrolysis characterized by?

Loss of intercellular bridges and eosinophilic cytoplasm Signup and view all the answers

Hypoplasia in the context of epidermal changes refers to what?

Decrease in the number of epidermal cells Signup and view all the answers

What type of epidermal change can result from hyperadrenocorticism?

Hypoplasia/atrophy Signup and view all the answers

What is the primary characteristic of exuberant granulation tissue?

A network of vertically oriented capillaries Signup and view all the answers

Which statement accurately describes fibrosis?

Fibrosis represents a later stage in the formation of fibrous tissue. Signup and view all the answers

What condition is characterized by the presence of melanin granules within the subepidermal dermis?

Pigmentary incontinence Signup and view all the answers

Which of the following describes papillomatosis?

Formation of an irregular epidermis due to dermal papillae projections Signup and view all the answers

What is a typical feature of dermal edema?

Dilated lymphatics and widened interstitial spaces Signup and view all the answers

In which condition is mucinous degeneration typically observed?

Canine hypothyroidism Signup and view all the answers

What are common changes seen in cutaneous blood vessels?

Dilatation and endothelial swelling Signup and view all the answers

Which of the following is a sign of follicular epithelium changes?

Dilatation and plugging in follicular keratosis Signup and view all the answers

Study Notes

Integumentary System: VPM 3419

The Integumentary system is the largest body system, forming an anatomical boundary between the animal and its environment.
Skin diseases are common in veterinary practice and can indicate systemic diseases, causing significant economic losses in food animals and zoonotic transmission.
Functions:
- Protection: Protects against ultraviolet light, mechanical, chemical, and thermal insults, acting as a barrier against water loss, electrolyte loss, macromolecules and micro-organism invasion.
- Sensation: Contains receptors for touch, pressure, pain, and temperature.
- Thermoregulation: Hairs and subcutaneous adipose tissue insulate the body against heat loss. Excess heat is evaporated through sweat and increased blood flow in the skin.
- Metabolic: Subcutaneous adipose tissue is a major energy store (triglycerides). Epidermis synthesizes Vitamin D.
- Motion, Shape, and Colour: Skin's flexibility, elasticity, and toughness allow movement and define shape and form. Processes in skin (melanin formation, vascularity, keratinization) influence coat and skin colour. Pigmentation prevents damage from solar radiation.
- Indicators: Skin can be a valuable indicator of internal diseases.

Skin Structure

Composed of epidermis, dermis, hair follicles, adnexal glands, and subcutis.
The structure shows layered features in different images of the skin.

Epidermis, Dermis and Hypodermis

Epidermis:
- Stratum basale (basal layer): single layer of cuboidal/columnar cells; mitosis is often limited.
- Stratum spinosum (prickle layer): several layers of polygonal cells
- Stratum granulosum (granular layer): one or more layers of nucleated, flattened keratinocytes.
- Stratum lucidum (clear layer): thin layer of flattened, unstained cells (found in paw and nose).
- Stratum corneum (horny layer): multiple layers of dead, fully keratinized, flattened cells.
Epidermal Appendages (Adnexa):
- Hair Follicles: simple (e.g., cattle, horses) and compound (e.g., sheep, dogs, cats). Hair follicles have cyclical growth (anagen, catagen, telogen). Hair follicles possess multiple components: shaft, bulb, papilla, internal root sheath, external root sheath, sebaceous gland, arrector pili muscle and apocrine sweat glands.
- Glands:
  - Sebaceous glands: part of hair follicle complex, secrete sebum (triglycerides + cholesterol).
  - Apocrine sweat glands: develop as part of hair follicle complex, opening into hair follicles; effective in hoofed animals.
  - Eccrine sweat glands: not associated with hair follicles; effective in mammals without hooves. Secrete water and salt.
Dermis (Corium):
- Support and nourish epidermis and appendages.
- Composed of collagen, reticulin, and elastin fibers embedded in ground substance.
- Contains fibroblasts, mast cells, lymphocytes, macrophages (few) also eosinophils & neutrophils.
- Has superficial and deep layers of different fiber density.
Hypodermis (Subcutis):
- Heat insulator, contributing to body shape.
- Composed of lipocytes, blood vessels, nerves, and connective tissue.
- Cutaneous vasculature (superficial, middle, deep). Nerve fibers follow blood vessels, lymphatics in superficial dermis.

Dermal Histopathology

Hyperkeratosis: thickened stratum corneum (absolute or relative). May be orthokeratotic or parakeratotic, focal or generalized.
Hypokeratosis: decreased stratum corneum thickness
Dyskeratosis: premature and faulty keratinization of viable cells in stratum spinosum
Hyperplasia/Acanthosis: increased epidermis thickness related to cell number in non-cornified epidermis
Hypoplasia/ Atrophy: reduced epidermis thickness related to decreased cell number or size of non-cornified epidermis
Necrosis/Necrolysis: death of cells or tissues; nuclear changes, loss of intercellular bridges, eosinophilia of cytoplasm
Intercellular Oedema (Spongiosis): widening of epidermis intercellular bridges (common in acute/subacute dermatosis)
Intracellular Oedema: increased cell size and cytoplasmic pallor (often from viral infection or artifacts, resembling freezing or improper fixation)
Ballooning Degeneration: swollen, eosinophilic cytoplasm/cells without vacuoles: common in viral infections
Hydrophic Degeneration: Intracellular oedema in the stratum basale; often associated with Lupus erythematosus or drug reactions
Acantholysis: loss of cohesion between epidermal cells; causing clefts, vesicles, and bullae (common in severe spongiosis or viral infection); may be caused by proteolytic enzymes
Exocytosis: migration of inflammatory cells into epidermis.
Clefts (lacunae): slit-like spaces without fluid
Microvesicles, vesicles, bullae: small to large fluid-filled spaces in or below the epidermis.
Microabscesses/Pustules: intraepidermal and subepidermal cavities containing inflammatory cells
Hyperpigmentation (hypermelanosis): increase/excess melanin in epidermis
Hypopigmentation (hypomelanosis): decrease in melanin deposition in epidermis
Crusts: consolidated, desiccated serum, keratin debris, and microbes. Can be serous, hemorrhagic, or cellular/seocellular. Crust may be various colours.
Horn cysts (keratin cysts): circular cysts surrounded by flattened epidermal cells with keratin layers.
Horn pearls (squamous pearls): focal circular structures of concentric keratin layers in the centre, often with dyskeratosis; often associated with squamous cell carcinoma.

Dermal Changes

Dermal collagen: collagen hyalinization with confluence; characterized by increased eosinophilia, glassy refractile appearance (often in chronic inflammation)
Fibrinoid degeneration: brightly eosinophilic fibrillar/granular substance resembling fibrin; indicative of connective tissue disease.
Fibrosis, Fibroplasia, Sclerosis: increase in fibrous tissue (e.g., granulation tissue), prominent fibroblast cells, and increased collagen fibrils (often with inflammation) ; sclerosis is a later stage of the process.
Exuberant Granulation Tissue: vertically and horizontally oriented capillaries and few collagen fibres.
Papillomatosis: projection of dermal papillae above skin surface, often with epidermal hyperplasia.
Pigmentary incontinence: presence of melanin granules free in subepidermal dermis and within dermal macrophages (melanophages).
Dermal oedema: widened perivascular interstitial spaces.
Mucinous degeneration: increase in amorphous, stringy, granular materials displacing collagen fibrils.
Follicular epithelium: Follicular keratosis, plugging and dilatation or atrophy of follicles, resulting from hormonal disease.
Sebaceous glands/apocrine, sweat glands: suppurative or granulomatous inflammations, atrophy, cysts, hyperplasia (related to chronic inflammation or hormonal disease).
Cutaneous blood Vessels: dilation, endothelial swelling, vasculitis or thromboembolism.

Subcutaneous Changes

Suppurative and granulomatous dermatoses.
Inflammatory changes (e.g., panniculitis, steatitis).
Necrosis.

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Description

Test your knowledge about the integumentary system and the functions of the epidermis. This quiz covers various aspects including skin structure, functions, and the role of hair follicles. Perfect for students studying anatomy or related fields.