Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Skin and Body Membranes Chapter 4 2 Types of Body Membranes A. Epithelial and B. Connective A. Epithelial Membrane=Skin, Mucous Membrane, Serous Membrane B. Connective Membranes=Synovial (areolar connective tissue) that has no Epithelial cells Epithelial Membranes Epithelial Membranes A. Cutaneous Membrane "Skin"-Only Dry Membrane Epidermis Dermis Skin (Integument) B. Mucous Membrane"Wet" Lining Exterior Opening Respitory, Digestive Urinary, Reproductive Wet Exterior Openings C. Serous Membrane (serosa) Lining Interior Occur in pairs like the "Balloon" example Interior Linings A. Cutaneous/Integument/Skin • • • • Waterproof-Stretchable-Washable Self-Repairs: Cuts, Rips, and Burns Electrical Insulation Includes: Sweat and Oil Glands, Hairs, and Nails Functions of the Skin Mechanical Damage Chemical Damage Bacterial Damage Ultraviolet Radiation Thermal Damage Desiccation Heat Loss/Retention Urea and Uric Acid Excretion Vitamin D Physical Barrier Acids and Bases Unbroken Surface, “Acid Mantle” Melanin protects from Sun Heat/Cold/Pain Receptors Waterproofing Surfaces Skin Capillary Access Perspiration Sunlight Skin Structure Epidermis A. Stratified Squamous B. Keratinizing (hardening) Dermis A. Dense Connective B. Contains Blood, Sweat, and Oil Glands Hypodermis A. A.K.A Subcuaneous tissue B. Adipose Tissue C. Anchor Skin (E&D) to underlying organs 3 Layers-Actual Picture Epidermis-5 Strata (Layers) *****OUTSIDE THE BODY***** E P I D E R M I S • • • • • Corneum Lucidum Granulosum Spinosum Basale *****DERMIS***** Why can we shave (face/legs) and not bleed? • The epidermis is AVASCULAR, meaning it has no blood supply of its own. • Most cells produce keratin (tough, fibrous protein) • Basale (alive with spino- and granulo-) absorbs nutrients, the top 2 (lucid- and corne-) are non-living Then why do you bleed when you shave? Because you cut too deeply and get into the DERMIS The 5 Strata Layers • • • • • Corneum:20-30 cells thick Lucidum: dead, clear cells found only on hands/feet Granulosum: still living cells Spinosum:living cells Basale: absorb nutrients from the dermis to keep them alive, and “float” up to form the above 4 layers New EPIdermis every 25-45 days • Suntans/burns occur in the Basale • Melanin (colored pigment) • Basale cells phagocytize (eat) the melanin • Melanin shields DNA from UV rays The Dermis • Divided into 2 LayersPapillary and Reticular Papillary Layer • Upper projections called papillae containing pain and touch receptors (known as Meissner’s corpuscles) Reticular Layer • Contains blood vessels, sweat and oil glands and deep pressure receptors (Pacinian corpusles) • Many phagocytes to attack bacteria that has passed through Epi• Collagen fibers and blood vessels