BI13_Ch5 PP Outline

BI13_Ch5 PP Outline - 1 2 The Integumentary System Chapter...

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1 The Integumentary System Chapter 5 2 Goals Learn the structure and function of the skin layers Understand normal and abnormal skin color Lean structure and function of skin appendages Understand what causes skin ailments 3 Functions of the Skin Protects underlying tissues Senses stimuli Prevents dehydration Aids in heat loss Keeps out microbes Makes vitamin D 4 Structure of Skin Epidermis: outer layer Strati±ed squamous epithelium Dermis: deeper layer Dense, ±brous connective tissue Hypodermis Adipose tissue just below skin Not technically skin 5 The Epidermis Layers Cells 6 Thick vs. Thin Skin Thick Contains 5 layers (strata) Stratum Lucidum Palms, ±ngertips, soles 7 Stratum Basale: Deepest Layer A single layer of cells Youngest keratinocytes Constant cell division Pushes older cells superiorly 8 Stratum Spinosum Several cell layers thick Cells contain thick bundles of intermediate ±laments Attached to desmosomes 9 Stratum Granulosum: Cells Toughen-up and Start to Die Cells ²atten Organelles disintegrate Plasma membrane thickens
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Plasma membrane thickens Granules accumulate Filled with proteins for toughening and waterproo±ng Cells above this layer are too far away from blood supply to live 10 Stratum Lucidum: Clear Layer Only found in thick skin Contains a few layers of clear, ²at, dead cells 11 Stratum Corneum: Most Super±cial Strati±ed squamous cells 20 - 30 cells thick Keratin protein Toughens Glycolipid Waterproofs Horny cells Flake o f = dandru f New skin every 25-40 days 12 Actual Skin Section 13 The Epidermis Layers Cells 14 Keratinocytes: Most Common Epidermal Cell Produced in the stratum basale and rise Fill with keratin and die Linked by desmosomes Millions rubbed o f every day Excess rubbing thickens epidermis Callus 15 Melanocytes: Produce Melanin Spider-shaped epithelial cells in stratum basale Melanin Pigment that protects DNA from UV light damage Transfer in granules to keratinocytes Suntan Melanin production is increased in response to sun exposure 16 Langerhans’ Cells: Immune Sentry Star-shaped dendritic cells Fixed macrophages Immune cells Digest (phagocytose) microorganisms trying to infect the body 17 Merkel Cells: Touch Receptors
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Located at the epidermis/dermis junction Merkel disk Merkel cell + sensory nerve ending Receptor for touch 18 Practice Test Questions Describe the location and function of the stratum basale.
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This note was uploaded on 08/12/2009 for the course BI 13 taught by Professor Alexasawa,ph.d during the Spring '09 term at College of the Desert.

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BI13_Ch5 PP Outline - 1 2 The Integumentary System Chapter...

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