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Chapter # 7 Skin Structure and Growth Why do we need to know this? • No matter how advanced the latest skin care technology may be, knowing how to care for skin begins with understanding its underlying structure and basic needs. As a licensed service provider, you must recognize adverse conditions, including inflamed skin conditions, diseases, and infectious skin disorders Basic Key Terms • Dermatology is the medical branch of science that deals with the study of skin, its nature, structure, functions, diseases, and treatments • Dermatologist is the physician engaged in the science of treating the skin • Esthetician is a specialist in the cleansing, preservation of health, and beautification of the skin and body Key Facts • The skin is the largest organ of the body • The skin of a typical 150 pound male weighs about 9 lbs • Our skin protects the muscles, bones, nerves, and everything else inside our bodies against the environment • Healthy skin is slightly moist, soft and flexible with a texture that is ideally smooth and fine grained • Healthy skin is slightly acidic 4.5-5.5 pH Key Fact Continued • Appendages of the skin are hair, nails, sweat, & oil glands • Eyelids are the thinnest skin • Sole of our feet have the thickest skin • Continued pressure on any part of the skin can cause it to thicken and develop into a callus • The scalp has larger and deeper hair follicles to accommodate the longer hair of the head Two Main Divisions of the Skin Epidermis & Dermis • Epidermis – outermost layer of the skin, also called the cuticle, contains no blood vessels but has many small nerve endings, made up of 5 layers • Dermis – underlying or inner layer of skin also called the cutis, corium or true skin. Highly sensitive layer of connective tissue, 25 times thicker than the epidermis, contains blood vessels, nerves, sweat & oil glands, lymph vessels, hair follicles, and the arrector pili muscle. It is made up of 2 layers 7 7 Epidermis & Dermis Epidermis Layers • • • • • Stratum Germinativum (basal cell layer) Stratum Spinosum Stratum Granulosum Stratum Lucidum Stratum Corneum Stratum Germinativum • Also called the basal cell layer • Deepest layer of the epidermis • Composed of several layers of differently shaped cells • It is the live layer that produces new epidermal skin cells and is responsible for the growth of the epidermis Stratum Spinosum • Spiny layer • Just above the basal cell layer • Beginning of the process that causes skin cells to shed Stratum Granulosum • Granular layer • Consists of cells that look like distinct granules • These cells are almost dead and are pushed to the surface to replace cells that are shed from the skin surface layer Stratum Lucidum • Clear transparent layer • Just under the skin surface • Consists of small cells through which light can pass Stratum Corneum • Horny layer • Outer layer of the epidermis • The layer that we see when we look at the skin • The layer that can be treated by an esthetician • Its scale like cells are continually being shed and replaced by cells coming to the surface from underneath Skin Cells • Skin cells are made up of KERATIN which is a fiber protein that is also the principal component of hair and nails. • The cells combine with lipids or fats produced by the skin to help make the stratum corneum a protective, waterproof layer Dermis • Papillary Layer • Reticular Layer • Subcutaneous Tissue Papillary Layer • Outer layer of the dermis directly beneath the epidermis • Here your will find the dermal papillae, hair follicles, capillaries, pigment producing cells, and tactile corpuscles Reticular Layer • Is the deeper layer of the dermis that supplies the skin with oxygen and nutrients • It contains the following structures within its network: fat cells, sweat glands, blood vessels, hair follicles, lymph vessels, arrector pili muscle, and oil glands Subcutaneous Tissue • Also called adipose or subcutis • Is the fatty layer found below the dermis • Varies in thickness according to the age, gender, and general health of the individual • It gives smoothness and contour to the body • It contains fats for use as energy and also acts as a protective cushion for the outer skin How is Skin Nourished • Blood supplies nutrients and oxygen to the skin • Lymph bathe the skin cells and remove toxins and cellular waste and have immune functions that help protect the skin against disease Nerves of the Skin / Sense of Touch • The skin contains motor nerve fibers, sensory nerve fibers, and sectetory nerve fibers • Nerve endings are most abundant in the fingertips • All of the nerve endings that provide the body with the sense of touch are housed in the papillary layer of the dermis Skin Color • Depends primarily on Melanin • Melanin is the tiny grains of pigment located in the basal cell layer of the epidermis and the papillary layer of the dermis • Color of skin is a hereditary trait and varies among races and nationalities • The body produces 2 types of melanin Pheomelanin which is red / yellow and Eumelanin which is Dark Brown to Black Strength and Flexibility of the Skin • The skin gets its strength, form, and flexibility from two specific structures which make up 70% of the dermis • Collagen • Elastin Collagen • A fibrous protein that gives the skin form and strength • Makes up a large portion of the dermis and gives structural support to the skin by holding together all the structures found in this layer • When healthy they allow the skin to stretch and contract as necessary • If they become weakened due to lack of moisture in the skin, or environmental damage the skin will begin to lose its tone and suppleness • Wrinkles and sagging are of the result of collagen fibers losing their strength Elastin • A protein base similar to collagen that forms elastic tissue • Gives skin its flexibility and elasticity • Helps the skin regain its shape even after being repeatedly stretched or expanded Glands of the Skin Sudoriferous & Sebaceous Sudoriferous Glands • Sweat glands excrete sweat from the skin • They have a tube-like duct that ends at the skin surface to form the sweat pore • Located on almost all parts of the body but are more numerous on the palms, soles, forehead, and armpits • They regulate body temperature. Their activity is increased by heat, exercise, emotions, and certain drugs • The excretion of sweat is controlled by the nervous system Glands of the Skin Sudoriferous & Sebaceous Sebaceous • Oil glands • Are connected to the hair follicles • Consist of little sacs with ducts that open into the follicles • These glands secrete sebum, a fatty or oil secretion that lubricates the skin and preserves the softness of the hair • These glands are found on all parts of the body except the palms and soles • When sebum hardens and the duct becomes clogged a comedone is formed which usually leads to a papule or pustule more commonly known as a pimple Functions of the Skin • Protection – from injury and bacterial invasions • Sensation – when the nerve endings are stimulated a message is sent to the brain • Heat Regulation – normal constant internal temperature is about 98.6 • Excretion – perspiration, cleansing of the body • Secretion – sebum or oil to lubricate the skin • Absorption – is limited but does occur, ingredients such as those in advanced skin care formulations may be absorbed between the cells and through the hair follicles and sebaceous gland openings Maintaining Skin Health • You are what you eat still holds true, proper diet choices help to regulate hydration, oil production, and overall function of the cells • Vitamins play an important role in the skin’s health Vitamins • Vitamin A – supports overall health of the skin, antioxidant which helps slow the process of aging and prevents certain cancers, often used to treat acne as Retin-A • Vitamin C – needed for proper repair of the skin and various tissues, this vitamin speeds up healing process, also key in the production of collagen which is useful for antiaging • Vitamin D – rapid healing of skin, the best source of this vitamin is sunlight in limited amounts (with sunscreen) it can also be obtained from Milk and OJ, helps support bone structure • Vitamin E – used with vitamin A helps fight against the harmful effects of the sun’s rays, heals damage to skins tissue, when used in a lotion helps heal sunburn and stretch marks WATER • There is one essential nutrient that no person can live without that that is WATER • The skin in order to function properly relies heavily upon water • Water composes 50-70% of our body weight • Drinking pure water is essential to the health of the skin and the body because it sustains the health of the cells, aids in the elimination of toxins and waste, regulates the body’s temperature and aids in proper digestion How much water each day? • Take your body weight divide by 16 • The result is the number of 8 ounce glasses that you should drink everyday • If you take part in intense physical activity add two extra glasses of water, that will help replace the extra fluids that are lost while exercising