Chapter 3- Physiology and Histology of the Skin

Chapter 3- Physiology and Histology of the Skin Largest organ of the body - Skin What are the 3 main layers of the skin? - Epidermis, dermis and hypodermis The body is made of 50-70% ______________ - Water Intecellular lipids, and keratin are produced in what layer of the skin? - Stratum granulosum Where is melanin produced? - Stratum germinativum Fibroblasts - Skin cells that aid in the production of collagen Glands that secrete oil - Sebaceous glands This product is known to stimulate cell turnover - Alpha hydroxy acids (AHAs) Free Radicals - Atoms or molecules with an unbalanced electrical charge Stratum Germinativum - aka: basal layer Where cells undergo cell division (mitosis) Contains melanocytes, which produce melanin Stratum Spinosum - aka: spiny layer Largest layer of the epidermis Provides strength and flexibility to the skin Contains Langerhans immune cells Stratum Granulosum - aka: granular layer; Layer of the epidermis composed of cells that look like granules and are filled with Keratin Replaces cells shed from the stratum corneum Stratum Lucidum - A thin, clear layer of small skin cells in the epidermis that let light pass through. The thickest on the palms of the hands and soles of the feet. Stratum Corneum - aka: horny layer Outer layer of the epidermis Regenerates itself, detoxifies the body and responds to stimuli Causes of premature aging - Smoking Certain drugs Tanning What external factor has the greatest aging affect on the skin? - UV rays/exposure Glycation - When blood sugar goes up rapidly and continually, the sugar attaches to the collagen in the skin, making it stiff and inflexible. Transepidermal Water Loss (TEWL) - Water loss caused by evaporation on the skin's surface. Estrogen - An anti-inflammatory, an antioxidant and a key factor in tissue repair. Responsible for maintaining coordination, balance, skin moisture, vision, bones and the nervous system. Primary functions of the skin - Protection, sensation, heat regulation, secretion, absorption, excretion As estrogen levels decrease, ___________________________ levels rise. - Testosterone Melanin - Pigment that protects us from the sun Everyone has the same number Stimulated by exposure to sunlight and protects the cells below by absorbing and blocking UV radiation. Layers of the dermis - Papillary and reticular Collagen - A protein substance of complex fibers that give skin its strength and is necessary for wound healing. Elastin - A fibrous protein that forms elastic tissue and gives skin its elasticity. True or false: the epidermis is thicker than the dermis - False Cell division is called: - Mitosis What is the acid mantle? - Protective layer of lipids and secretions on the skin's surface Consists of sebum, lipids, sweat and water Why does the body perspire? - To protect us from overheating What is a follicle? - Tube-like depressions in the epidermis with oil glands attached. What is a hydrolipidic film? - Oil-water balance that protects the skin's surface Fiber protein found in skin, hair and nails - Keratin When the arrector pili muscles contract, they cause : - Goosebumps Ceramides - Waxy lipid molecules important to barrier function and water-holding capacity How long is the average adult's cell turnover rate, depending on a person's age and lifestyle? - 28 days Another name for the subcutaneous layer - Hypodermis Another name for subcutis? - Adipose tissue Sudoriferous glands - Excrete perspiration, regulate body temperature, and detoxify the body Causes of couperose skin, or telangiectasia - Some causes of vasodilation include heredity, alimentary (digestive) problems, alcohol, smoking, sun damage, harsh cosmetics, trauma, pregnancy, excessive localized heat, topical corticosteroids, inflammation, and heat-cold fluctuations. What is a common term for clients to use describing follicles? - Pores What causes the body to produce its own vitamin D? - Exposure to the sun What does the enzyme tyrosinase do? - Stimulates melanocytes and produces melanin. Keratinocytes - Cells composed of keratin, comprise 95% of the epidermis. Contain proteins and lipids. Melanocytes - Cells that produce skin pigment granules in the basal layer What is the pH of the acid mantle? - 5.5