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Anatomy & Physiology: Integumentary System

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  • What are the two main parts of the integument?

    The integument consists of the cutaneous membrane (epidermis and dermis) and accessory structures such as hair, nails, and glands.

  • Describe the epidermis.

    The epidermis is a keratinized stratified squamous epithelium, avascular, with layers including stratum basale, spinosum, granulosum, lucidum (thick skin only), and corneum.

  • What is the function of melanocytes in the epidermis?

    Melanocytes synthesize melanin, a brown to black pigment that protects DNA by absorbing UV radiation.

  • What is the role of Langerhans cells?

    Langerhans cells are macrophages in the epidermis that guard against microbes, pathogens, and toxins and alert the immune system.

  • What is the function of Merkel cells?

    Merkel cells are sensory cells in the stratum basale that provide the sense of touch.

  • What are the layers of the epidermis from deepest to most superficial?

    Stratum basale, stratum spinosum, stratum granulosum, stratum lucidum (only in thick skin), and stratum corneum.

  • What is the dermis composed of?

    The dermis contains blood vessels, collagen fibers, hair follicles, sebaceous and sweat glands, nerve endings, and the erector pili muscle.

  • What are the two layers of the dermis?

    The papillary layer (upper 1/3, areolar connective tissue) and the reticular layer (bottom 2/3, dense irregular connective tissue).

  • What is the hypodermis?

    The hypodermis, or subcutaneous layer, is not part of the skin and consists mainly of adipose and areolar connective tissue with blood vessels and nerves.

  • What are the functions of the integumentary system?

    Protection, excretion, vitamin D synthesis, sensory reception, thermoregulation, and social functions like facial expression.

  • How does the skin regulate temperature in cold environments?

    By vasoconstriction to reduce blood flow to the skin and shivering to generate heat through muscle contractions.

  • How does the skin regulate temperature in hot environments?

    By vasodilation to increase blood flow to the skin and promote heat loss through sweating.

  • What is keratin and its role in the skin?

    Keratin is a tough protein in keratinocytes that provides protection and waterproofing to the skin, hair, and nails.

  • Describe the structure of a hair follicle.

    Hair follicles have a hair bulb with a papilla and matrix for growth, surrounded by internal and external root sheaths and a connective tissue sheath.

  • What are the three layers of the hair shaft?

    The medulla (core), cortex (thick keratin layer), and cuticle (overlapping keratin cells, protective scale).

  • What are the main types of sweat glands?

    Eccrine (merocrine) glands produce watery sweat for thermoregulation; apocrine glands produce thicker sweat with lipids and proteins, found in axilla and genital regions.

  • What is the function of sebaceous glands?

    Sebaceous glands secrete sebum to waterproof skin and hair, keep them pliable, and inhibit bacterial growth.

  • What are the classifications of burns?

    1st degree: epidermis only; 2nd degree: epidermis and dermis with blistering; 3rd degree: full thickness including hypodermis.

  • What is the Rule of Nines in burn assessment?

    A method to estimate body surface area affected by burns, dividing the body into regions each representing 9% or multiples thereof.

  • What causes fingerprints?

    Friction ridges formed by epidermal ridges and underlying dermal papillae create unique fingerprint patterns.