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Lecture on Cutaneous Membrane and Accessory Structures

Explore the composition, layers, functions, and clinical aspects of cutaneous membrane and its accessory structures like hair follicles, skin glands, and nails. Learn about pigmentation, dermal layers, sweat glands, and more. Discover the relationship between skin structure and aging process.

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Lecture on Cutaneous Membrane and Accessory Structures

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  1. Lecture on Cutaneous Membrane and Accessory Structures www.AssignmentPoint.com

  2. Made up of all 4 tissue types . . . .??

  3. Two Major Subdivisions • Cutaneous Membrane • Epidermis • Dermis • Hypodermis • Accessory Structures • Excretory glands (?) • ? • ?

  4. Epidermis • Type of Epithelium? • _vascular • Different layers (=strata) • 4 layers in thin skin • 5 layers in thick skin

  5. Stratum Germinativum Cell types: • Stem cells (basal cells) • Melanocytes • Merkel cells (touch receptors in hairless skin only) = stratum basale Stratum germinativum Innermost, single layer

  6. Stratum Spinosum • Stem cell daughter cells (some can still divide) • Melanocytes & Langerhans cells • Establishment of Desmosomes Stratum spinosum Several cells thick

  7. Stratum Granulosum • Cells displaced from stratum spinosum  Keratinocytes • Production of keratohyalin and keratin fibers • Cells start to die. Dehydration leaves interlocked layers of keratin, keratohyalin & PL membranes Stratum granulosum

  8. Stratum Lucidum • In palms of hands and soles of feet • Cells do not stain well  clear (lucid) looking Stratum lucidum

  9. Stratum Corneum • Many layers of flattened, dead cells, filled with keratin • Continually shed in sheaths • Water-resistant but not water proof ( insensible perspiration) • Relatively dry - advantage? • Keratinization occurs everywhere except for anterior surface of eye Stratum corneum 15-30 layers (much thicker in thick skin)

  10. Up to 6 x thicker Where?? Average 0.08 mm Rest of body Thin vs. Thick Skin Refers to epidermis

  11. Contour of skin surface follows pattern of epidermal ridges. Advantage ?? c c Unique fingerprints

  12. Skin Color depends on3 pigments • Hemoglobin (dermal blood supply) • Reddish tones • Pale, due to? • Bluish (=?), due to? • Melanin • Produced by melanocytes of stratum basale • Carotene • Obtained from plant foods

  13. Melanocytes Function ? Number of melanocytes same in all people, production levels differ !

  14. Papillary layer loose c.t. Reticular layer dense irregular c.t. Dermis

  15. Papillary Layer • Dermal papillae project between epidermal ridges. Consist of • Loose c.t. = _____ • Capillaries • Tactile receptors M

  16. Reticular Layer Consist of • ______________ c.t. • + ?? Pacinian corpuscule (deep pressure)

  17. Hypodermis • 2 other names ? • Indistinct boundary (c.t. fibers interwoven) Made up of • Loose c.t. + lots of . . . Function • Stabilization of skin while allowing for independent movement

  18. Clinical Brief: • Wrinkles • Stretch marks (lineae albicantes) • Decubitus • Transdermal medication • Advantage and disadvantage? • Examples? • Hypodermic needles Lines of cleavage

  19. Accessory Structures: Hair Follicles & Hair • 5 mio hair/hu body. (98% not on top of head) • Three hair types (vellus – intermediate – terminal) • Function ? • Hair color • Growth cycle

  20. Skin Glands: 1) Sebaceous Glands Holocrine Sebum discharged into hair follicles (lubrication & bactericidal) excessive shampooing leads to dry & brittle hair Sebaceous follicles, = Large sebaceous glands, discharge directly to epidermis Where ? Folliculitis; furuncle (boil); acne

  21. 2) Apocrine Sweat Glands • Have merocrine secretion!! • Empty into hair follicle • Location: armpits, groin, nipples • Viscous, cloudy secretion  good nutrient source for bacteria (odor !!) • Secretion may contain Pheromones • Secretion begins at puberty and is stimulated during emotional distress (cold sweat)

  22. 3) Merocrine Sweat Glands • Empty directly onto skin surface • Location: most all over body (esp. abundant on palms & soles: ~ 500/cm2) • Clear, watery secretion (99% H2O; rest NaCl + some waste products) • Sensible perspiration; Function: ?

  23. For purpose of completion: Other integumentary Glands: • Mammary glands: Modified apocrine sweat glands • Ceruminous glands: modified sweat glands in __________

  24. Nails not covered. Skin and Aging Process The End

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