3. SKIN or INTEGUMENT: Roles chemical-mechanical PROTECTION water loss radiation bugs immune SENSORY THERMOREGULATION METABOLISM vitamin D fat storage COMMUNICATION MECHANICAL friction surface scratching WABeresford
5. EPIDERMIS: Cell types Keratinocytes Langerhans APC cell immunity Melanocyte to make & transfer pigment Merkel cell sensory dead alive Nerve cell represented by its axon
6. EPIDERMIS: Layers & events STRATUM CORNEUM of dead, but attached, ‘hardened & wrapped‘ cells , will slough off S. GRANULOSUM multiple syntheses to make cornified cells S. SPINOSUM upward migration of keratinocytes, while keratins IFs increase & change S. BASALE mitosis of stem cells Keratinocyte differentiation } }
8. capillary loop EPIDERMIS } Pacinian corpuscle THICK, HAIRLESS SKIN no hair follicles no sebaceous glands sweat gland opens at top of ridge dermal papilla dense thick collagen fibers + elastic fibers secretory profiles of coiled tubule coiled duct of sweat gland &
9. THIN HAIRY SKIN Papilla of Hair follicle Root sheath Hair shaft Sebaceous gland Arrector pili muscle Sweat gland D E R M I S Epidermis HYPODERMIS Matrix
10. Autonomic motor Sweat gland D E R M I S Epidermis Vessel vasomotor THIN HAIRY SKIN: Innervation Arrector pili muscle pilomotor sudomotor Sensory
12. { MOLECULAR EPIDERMIS CORNEUM CELLS ANCHORING FIBRILS LAMINA DENSA LAMINA LUCIDA HEMIDESMOSOMES BASAL CELL type VII collagen laminin type IV collagen epiligrin BM 600 anchoring filaments glycolipid cadherin-P T-transglutaminase 1 keratins hemidesmosomal proteins integrin a6b4 {
13. MOLECULAR EPIDERMIS * CORNEUM CELLS ANCHORING FIBRILS LAMINA DENSA LAMINA LUCIDA HEMIDESMOSOMES BASAL CELL type VII collagen laminin type IV collagen epiligrin BM 600 anchoring filaments glycolipid cadherin-P T-transglutaminase 1 keratins hemidesmosomal proteins integrin a6b4 Clinical significance: genetic defects in, or autoimmune attack on, a particular kind of molecule may cause dysfunction. For instance, trouble with collagen VII allows the epidermis to separate from the dermis - a blister or ‘bullous’ state genetic form is dystrophic epidermolysis bullosa { {
14. HAIR FOLLICLE: LAYERS at one cross-section Medulla Cortex Cuticle Cuticle Huxley’s layer Henle’s layer OUTER ROOT SHEATH CT sheath INNER ROOT SHEATH HAIR SHAFT 4 3 2 1 Before getting lost in the layering, note the 4 main parts. For the matrix & dermal papilla, see next Hair bulb
16. HAIR FOLLICLE 4 There are two cuticles, so that the hair’s can separate from the follicle’s for the hair to move & be coated with greasy sebum HAIR SHAFT Medulla OUTER ROOT SHEATH CT sheath Cortex Cuticle DERMAL PAPILLA MATRIX 1 3 4 5 6 Medulla Cortex Cuticle HAIR SHAFT OUTER ROOT SHEATH is continuous with the epidermis 2 includes pigment cells for hair color Cuticle Huxley’s layer Henle’s layer INNER ROOT SHEATH
17. CYCLE OF HAIR GROWTH Rate of growth ANAGEN CATAGEN ANAGEN Time TELOGEN TELOGEN (end) quiescence shedding ANAGEN regrowth of matrix & papilla, then hair ANAGEN growth CATAGEN breakdown