Epidermis: Stratum Granulosum

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1 Epidermis: Stratum Granulosum 1-5 layers of flattened, polygonal cells Keratohyalin granules: filaggrin and keratin filaments Lamellar granules: lipid & protein rich, produce intercellular cement

2 Stratum Granulosum Cell Magnified Thick SG membrane or cell envelope Intercellular space Keratin filaments Lamellar Granules with lamellae are on outer edge of stratum granulosum cell (yellow arrows) The lipid complex is discharged into intercellular space Keratin filaments are still obvious The cell membrane of the SG cell is thicker

3 Epidermis: Stratum Corneum Outermost layer of corneocytes The protective barrier - selectively permeable Filled with filaments of keratin and NMF Stratum Disjunctum Cell membrane thickens to form cell envelope Stratum Dysjunctum continuously shed

4 Stratum Corneum Modified desmosomes Transition from Stratum Granulosum to Stratum Corneum: Cells flatten Compact keratin filaments Desmosomes alter & weaken Cell membrane thickens to form envelope Loss of organelles Flattened keratinocytes are pushed upwards SC SG Keratin filaments (KF)

5 Barrier Function Corneocytes (bricks) are embedded Lipid lamellae resembles bricks & mortar NMF is present within the corneocytes Cell envelope helps retain water surface deep Cell envelope Corneocyte bricks brick NMF Lipid mortar mortar NMF NMF brick

6 Stratum Corneum Cell Magnified Thickened cell membrane (AKA cell envelope) Keratin filaments in matrix Intercellular lipids from granules

7 NMF Released by keratohyalin granules Profilaggrin à filaggrin à amino acids à NMF Stays inside corneocyte cells Gives Stratum Corneum its water binding properties Provides aqueous environment for enzymes i.e. corneodesmosome degradation NMF declines with age; reduced with UV exposure

8 Lipids Ceramides (50%), cholesterol (25%), fatty acids (10-20%) Lipids are produced and extruded by lamellar granules Help prevent TEWL & bacteria from entering skin Help prevent water soluble agents from entering skin Lipids affected by age, genetics, seasonal variation, & diet Skin must generate mg lipid/day to replace lipids lost in desquamation

9 Role of Lipids Ruthenium Tetroxide Fixation Lipids are responsible for maintaining skin hydration Ceramide 1: rich in linoleic acid, plays a major role in structuring SC lipids essential for barrier function Six ceramides have now been identified Ratio of fatty acids, ceramides and cholesterol is critical in maintaining skin moisture

10 Factors Affecting Barrier Function Age, environment, diet & disease all affect the barrier function Cleansers & retinoids alter the barrier Stress: elevates glucocorticoid levels which delay barrier recovery The sensitized skin condition is often the result of a compromised barrier function

11 Sensation Heat regulation Protection Functions of the Skin Excretion Absorption

12 Relevant Factor Understanding the function of the skin and how each layer of the skin responds to external elements gives the skin therapist the ability to effectively: Choose the correct course of treatment for each client; Dehydration, aging skin, pigmentation, acne Communicate and educate the client on protecting and maintaining the health of their skin (client retention and referrals) Eagerly take on Advanced therapies and modalities

13 You now know

14 And we re just getting started!

15 The Dermal-Epidermal Junction (DEJ) Epidermal Pegs Dermal Papillae Duct of Sweat Gland Finger-like projections of the epidermis extend into the dermis: epidermal pegs or rete pegs The dermal-hypodermal junction is less obvious. Sweat glands Attachment proteins in DEJ Sweat glands are in this area. Skin 101 to be continued

16 Creative projects A very fun and interactive exercise!! Group or Individual class project takes about minutes to do and you can color coordinate with the colors on the skin chart. Materials for this exercise are easily obtained at a craft or art store Styrofoam blocks 4 x 4 Markers, glue, and scissors Multi-color yarn, string or pipe cleaners

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20 Skin is Awesome! Improve student engagement through more ACTIVE learning strategies Plan your lessons with the end result in mind Make it Fun and it will be interesting!

21 Class Objectives Teach with Confidence know and love your subject Make it Interactive appeal to mixed generations and learning styles Make it Relevant - how will this help me within my practice Make it Fun! That s obvious

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23 Acknowledgements and resources: APS: Go to ITunes App store Cells and Cell Structure Videos, interactive activities; V-Cell virtual Anatomy 3D Organs;$1.99 App store TED videos educational and motivating Many thanks to our Skin Council Team!