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Bone, Muscle and Skin. Normal Function of Skin Deborah H. Damon, Ph.D..

Skin Function Protection Calcium/Vitamin D Sensory Thermoregulation.

Skin Function Protection. Epider Skin Stratu corneum straturn Epidermis Stratum AMP Corneocytes.

Skin Function Protection. The corneocytes and surrounding lipid matrix is part of a “wall” that protects our internal environment from t he external environment. Pathogens and harmful chemicals are kept out; water is kept in.

. Skin Function Protection: Skin Immunology. CD8• T cell Dermal DC ILC Langerhans Cell CD4+ T cell Sebaceous Gland Macrophage.

Epidermis: Stratum corneum Stratum granulosum Stratum spinosum Stratum germinativum (basal layer) Epidermal melanin unit Keratinocytes Melanocytes Melanocyte Melanosomes.

. Skin Function UV Protection Synthesis of Melanins.

Image result for melanocyte. Skin Function UV Protection: Melanin and Skin Color.

. Skin Function UV Protection. X-rays Vacuum c A Light KERATINOCYTE Sunscreen Agents p53 1 POMC Eumelanin Transfer to Keratinocytes Y-MSH ACTH ß- endorphin a-MSH MELANOCYTE MclR Melanosomes Melanin.

Skin Function Protection: Sebaceous Glands. e xocrine glands that produce sebum, an o il secretion that moisturizes skin and hair o pen into hair follicles f ound everywhere on the body except palms, s oles of feet and lower lip.

. UVB wavelengths 290-315nm 7-dehydrocholesterol in skin Previtamin D3 (cholecalciferol) liver Inactive 2S- hydrorpitamln 03 (calcldlol) kidney Active vitamin 03 (calcitriol).

. o la-hydroxylase o VDR o o DNAbinding RXR AF-2 VDR RXR VDR RXR NUCLEUS Ligand binding Tissue specific cellular responses mRNA.

. Skin Function Vitamin D.

. Skin Function Vitamin D and Calcium. VDR Intestine VDR Kidney PTHR VDR Bone PTHR t Serum Calcium.

Sensory Neuron Peripheral branch Dendron Receptor cells Myelin sheath Soma Axon terminals (Conduct impulses to the CNS) Axon Central branch o o.

C fibre These unmyelinated nerve fibres are found only in hairy skin. Although sensitive to indentation, they are most active when a stimulus moves slowly across the skin's surface. S 84 1 NATURE I VOL Ruffini ending Found in the dermis of both hairy and glabrous skin. these sensory receptors respond optimally to stretching of skin. 563 1 22 NOVEMBER Pacinian corpuscle Located deep in the dermis of both types of skin, Pacinian corpuscles respond to high-frequency vibration. 2018 Meissner corpuscle These nerve receptors lie just beneath the epidermis of glabrous skin, where they detect movement across the skin and fluttering touch. Merkel cell Part of the stratum basale of the epidermis, these cells help to relay information about the texture, curvature and shape Of objects. Merkel cells are most dense in glabrous skin..

. Skin Function Sensation: Free Nerve Endings: Nociceptors.

. 1. Chemotaxis and activation 2. Vascular dilation, permeability and adhesion 00 3. Dendritic and T-cell priming 0 00 Neuronally released 0 00 mediators.

. Release of sp 107 Pain Transmission SP-containing Sensory Nerve Keratinocyte Proliferation Migration Neutrophils Macroph ages Phagocytosis Chemotaxis Noxious Stimuli T cells Immune Regulation Endothelial wlls Vasodilation Plasma Leakage.

Skin Function Thermoregulation. Hypothermia pyrexia Hyperthermia Death 932 95.0 96.8 98.6 1Ø.4 1022104 1058 107.6 109.4 1112 34 35 36 37 38 Average normal range 39 40 41 42 4-3 44.

Skin Function Thermoregulation. Heat production • Basal metabolism • Muscular activity (shivering) • Thyroxine and epi- nephrine (stimulat- ing effects on meta- bolic rate) • Temperature effect on cells C 2C01 Cummings, an Enprint 01 Heat loss • Radiation • Conduction [convection • Evaporation.

Skin Function Thermoregulation: Homeostasis.

. Skin Function Thermoregulation: Homeostasis.

. Bb:d dlates (vu:dlation) Heat bs epidermis Epidermis Ircreaæd heat bss Blood oxgtrict8 (vancostricticn) Heat unservaicn.

Skin Function Thermoregulation: Piloerection.

hair skin arr«nor pili nuscle relaxed goosebunv arr«nor pili nuscle tens«i.

Skin Function Thermoregulation: Sweat. Sweat pore Hair follicle Eccrine sweat gland Apocrine sweat gland MAYO FOUNDATION FOR MECOCAL ECO-CATION ANO RESEARCH. RIGHTS RESERVED..

. Skin Function Thermoregulation: Eccrine Sweat. O Naa H 20 0 00000 Isotonic secretion Secretory coil Reabsorptive duct H20 ooo NaCl absorption Hypotonic sweat Cholinergic Adrenergic.

. Central thermcoenzors Peripheral themuennrs hpcthdanu.ß Sympahetic nervous ry•stemt cholinergic at-dmergic Hea bz evp«atbn gcd '*Zds Interra Row ofheat (core -+ skin) h•dreneryc fct Non-shiering therrroenens (h lnGTts) Sornstic nervcus cholinergic Qdetd — n-tsde Heat productbn by Zhi.ering.

. Hair Arrector Pili Muscle Sweat Gland Sensory Nerve Cutaneous Artery Cutaneuous Vein Adipse Tissue pathetic Nerve.

. Skin Function: Thermoregulation Neural Control: Sympathetic.