Questions and Answers
Which cell type is primarily responsible for the immune protection of the skin?
Which of the following components is NOT found in the dermis layer of the skin?
What function does the integumentary system primarily perform related to sensation?
Which skin appendage is responsible for the secretion of sweat?
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Which layer of the skin contains lipocytes and serves as a subcutaneous layer?
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What is the primary function of melanocytes in the skin?
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Which component is not a function of the integumentary system?
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Which type of skin related structure is NOT included under adnexa?
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What is leukoderma associated with?
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Which factor does NOT affect melanin pigment production?
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What is characterized by a circular rim of keratin flakes following loss of the roof of a vesicle or pustule?
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Which of the following describes lichenification?
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What is a key feature of hyperpigmentation as opposed to hypopigmentation?
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What is the primary characteristic of a bulla?
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Which condition is characterized by an accumulation of pus within the epidermis or follicle?
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Which term describes a dilated hair follicle filled with cornified cells?
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What is the distinguishing feature of wheals in horses?
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Which of the following conditions is characterized by more hair than normal?
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What is hyperpigmentation primarily due to?
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What does hypotrichosis refer to?
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Which condition is caused by the failure of melanocytes to produce melanin?
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Which of the following is NOT considered a primary lesion in dermatology?
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What is the characteristic size of a macule in dermatological terms?
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Which factor is classified as an endogenous factor causing skin injury?
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What condition is described as a benign heritable form of hyperpigmentation?
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How do secondary lesions typically arise?
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In terms of size, what defines a nodule in dermatological evaluation?
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What is the primary function of dermal vessels in the skin?
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Which of the following is a metabolic function of the skin?
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Study Notes
Structure of the Integumentary System
- Skin is the largest organ of the body, comprising both haired and hairless portions.
- Consists of four main components: epidermis, dermis, adnexa, and hypodermis.
Epidermis
- Made of various cell types: keratinocytes, melanocytes, Langerhans cells, and Merkel cells.
- Keratinocytes produce keratin; melanocytes produce melanin; Langerhans cells are involved in immune protection.
Dermis
- Composed of fibers (collagen, reticulin, elastin), ground substance (glycosaminoglycans, proteoglycans), cells (fibroblasts, mast cells, histiocytes, smooth muscle), vessels (blood and lymph), and nerves.
Adnexa (Appendages of the Skin)
- Comprises hair, glands (sebaceous, apocrine, eccrine), claws/nails, and hooves.
Hypodermis (Subcutis)
- Contains lipocytes, collagen, elastin fibers, and various vessels and nerves.
Functions of the Integumentary System
- Provides barriers against pathogens, dehydration, and UV radiation.
- Facilitates cutaneous sensations: touch, temperature, pressure, pain, and itch.
- Regulates body temperature through thermoregulation.
- Engages in metabolic functions like vitamin D production and storage of water, electrolytes, and proteins.
- Acts as a blood reservoir through dermal vessels.
Response of Skin to Injury
- Injuries may originate from exogenous (external) or endogenous (internal) factors.
- Histopathology tests, such as biopsies and blood tests, can help determine injury etiology.
Gross Morphology of Skin Lesions
- Primary lesions are direct manifestations of disease; secondary lesions evolve from primary lesions.
Types of Primary Lesions
- Macule: Discolored area ≤1 cm.
- Papule: Small solid elevation <1 cm.
- Plaque: Flat-topped solid elevation.
- Nodule: Solid elevation >1 cm, often deeper.
- Vesicle: Well-defined elevation <1 cm, filled with clear fluid.
- Bulla: Large vesicle >1 cm.
- Tumor: Large neoplastic mass in skin/subcutis.
- Cyst: Fluid- or solid-filled epithelial cavity.
- Pustule: Small pus-filled elevation.
- Abscess: Pus accumulation in epidermis or follicle.
- Wheal: Smooth, sharply circumscribed elevation due to edema.
Secondary Lesions
- Scale: Flakes or dandruff on skin surface.
- Crust: Dried exudate or blood adhered to skin.
- Comedo: Dilated hair follicle filled with cornified cells.
- Alopecia: Hair loss.
- Hypotrichosis: Less hair than normal; atrichia means absence.
- Effluvium: Excessive hair shedding.
- Hypertrichosis: Excess hair.
Alterations in Epidermal Pigmentation
- Hyperpigmentation: Increased melanin production.
- Hypopigmentation: Due to lack of melanocytes or production failure.
- Pigmentation Incontinence: Melanin loss from the epidermis.
Factors Affecting Melanin Production
- Influenced by melanocyte-stimulating hormone, age, inflammation, temperature, and genetics.
Secondary Lesion Characteristics
- Epidermal collarette: Circular rim of keratin flakes from vesicle/pustule loss.
- Ulcer: Break in epidermis exposing the dermis.
- Excoriation: Erosion or ulcer from trauma.
- Scar: Fibrous tissue replacing damaged dermis/subcutis.
- Fissure: Linear cleavage in thickened skin.
- Lichenification: Thickening and hardening with exaggerated skin markings.
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Description
This quiz covers the structure of the integumentary system, specifically focusing on the skin's components, including the epidermis and dermis. Understanding the normal structure and functions of the skin is crucial for veterinary students in VET 2133.
