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Anatomy & Physiology: Integumentary System Study Guide

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Terms in this set (31)

  • Two layers of the cutaneous membrane

    Epidermis: keratinized stratified squamous epithelium.
    Dermis: loose and dense connective tissue.

  • Stimuli detected by sensory nerves in the skin

    Touch, temperature, pain, vibration, and pressure.

  • How does the avascular epidermis receive nutrients?

    Oxygen and nutrients diffuse from capillaries in the dermis.

  • Difference between thin and thick skin

    Thin skin lacks the stratum lucidum and has 4 epidermal layers; found over most of the body.
    Thick skin contains the stratum lucidum and has 5 layers; found on palms and soles.

  • Five strata of thick skin from deep to superficial

    Stratum basale, spinosum, granulosum, lucidum, corneum.

  • Role of basement membrane, hemidesmosomes, and epidermal ridges

    Hemidesmosomes attach basal epidermal cells to the basement membrane; epidermal ridges interlock with dermal papillae to anchor epidermis to dermis.

  • Three cell types in stratum basale and their functions

    Basal (stem) cells: produce new keratinocytes.
    Melanocytes: synthesize melanin for UV protection.
    Tactile (Merkel) cells: sensory for touch.

  • Why keratinocytes in stratum spinosum appear spiny

    Due to desmosomes connecting cells with tree-like branching, providing strength and resistance to stress.

  • Epidermal cells providing immune defense and their location

    Dendritic (Langerhans) cells in the stratum spinosum defend against microorganisms and skin cancer cells.

  • Keratinocyte changes from stratum basale to corneum

    Born in basale (cell division), keratinization begins in granulosum, cells lose organelles and die, forming dead corneocytes in corneum that are shed continuously.

  • Difference between insensible and sensible perspiration

    Insensible: water diffuses across stratum corneum, not felt.
    Sensible: water excreted by sweat glands to cool body.

  • Function of epidermal growth factor (EGF)

    Stimulates epithelial cell growth and repair, including glands in the duodenum and salivary glands.

  • Differences between papillary and reticular dermis layers

    Papillary: superficial, loose areolar connective tissue, contains capillaries and Meissner's corpuscles.
    Reticular: deeper, dense irregular connective tissue with collagen and elastic fibers, provides strength and elasticity.

  • Role of collagen and elastic fibers in skin

    Collagen fibers provide tensile strength and water-binding; elastic fibers allow recoil and maintain skin turgor.

  • Why incisions parallel to tension lines heal better

    Parallel cuts align with collagen fibers, keeping wounds closed and reducing scarring; perpendicular cuts pull wounds open.

  • Effect of dehydration vs aging on skin turgor and elasticity

    Dehydration reduces interstitial fluid causing loss of turgor; aging reduces elastic fibers causing loss of recoil and wrinkles.

  • Comparison of Merkel cells, Meissner’s corpuscles, and Pacinian corpuscles

    Merkel: in stratum basale, senses light touch.
    Meissner's: in dermal papillae, senses light touch and low-frequency vibration.
    Pacinian: deep dermis/subcutaneous, senses deep pressure and vibration.

  • Why is the subcutaneous layer not part of the cutaneous membrane?

    It lies below the dermis, separating skin from deep fascia; composed mainly of adipose tissue for energy storage and insulation.

  • Contributions of carotene, melanin, and hemoglobin to skin color

    Carotene: yellow/orange pigment.
    Melanin: brown/tan pigment from melanocytes.
    Hemoglobin: red color from blood oxygenation.

  • How melanin is transferred and affects skin pigmentation

    Melanocytes package melanin in vesicles (melanosomes) transferred to keratinocytes; more melanosomes produce darker skin.

  • Effect of sunlight on melanin production and protection

    Sunlight increases melanin production, which protects skin cells from UV-induced DNA damage.

  • How dermal blood flow affects skin color changes

    Increased blood flow causes redness; decreased flow and oxygen cause cyanosis (bluish skin); low melanin causes paleness.

  • Difference between albinism and vitiligo

    Albinism: genetic lack of melanin.
    Vitiligo: autoimmune loss of melanin in patches.
    Both increase UV susceptibility.

  • Cause of jaundice and Addison’s disease skin color changes

    Jaundice: yellowing from bilirubin buildup.
    Addison’s: increased ACTH stimulates melanin, darkening skin.

  • Comparison of basal cell carcinoma, squamous cell carcinoma, and malignant melanoma

    Basal cell: from stratum basale, common, rarely metastasizes.
    Squamous cell: from squamous cells, caused by UV, rarely metastasizes.
    Melanoma: from melanocytes, aggressive, often metastasizes.

  • Warning signs of melanoma in moles

    Asymmetry, irregular borders, mottled color, size >6 mm, and changes in size, shape, or color.

  • Another term for Vitamin D3 and its production

    Cholecalciferol; produced by epidermal cells stimulated by UV rays.

  • Organs converting cholecalciferol to calcitriol

    Liver and kidneys convert cholecalciferol into active hormone calcitriol.

  • Role of calcitriol in calcium metabolism

    Calcitriol promotes absorption of calcium and phosphate ions in the small intestine.

  • How hair protects the body and produces sensation

    Hair protects skin from microorganisms; movement sensed by root hair plexus of sensory nerves.

  • Function of arrector pili muscle

    Contracts to pull hair upright, causing goose bumps.