Integumentary System 1 Describe the components of the integumentary system a The Integument i The largest system of the body ii 16 of body weight 1 5 to 2 m2 in area b Components i Cutaneous Membrane Skin 1 Outer Epidermis a Superficial epithelium epithelial tissues 2 Inner Dermis a Connective tissues ii Accessory Structures iii Hypodermis 1 Originate in the dermis 2 Extend through the epidermis to the skin surface 3 Includes a Hair b Nails c Multicellular Exocrine Glands 1 Superficial Fascia or Subcutaneous Layer 2 NOT part of the integumentary system 3 Located below the dermis 4 Loose connective tissue a Separates integument from the deep fascia around other organs 5 Location of hypodermic injections 2 What are the accessory structures What are their functions a Hair b Nails c Multicellular Exocrine Glands and nervous system a Cardiovascular System i Blood vessels in the dermis b Nervous System 3 Explain how the integumentary system is linked to the cardiovascular i Sensory receptors for pain touch and temperature ii Receptors relay this information to the CNS 4 Describe the main functions of the cutaneous membrane a Protection attack i Protects underlying tissues and organs ii Protects against impact abrasion fluid loss and chemical b Excretion i Excretes salts water and organic wastes glands ii Excreted by integumentary glands c Maintenance 1 d Production i Maintains body temperature Insulation and evaporation i Produces 1 Melanin 2 Keratin repellent 3 Vitamin D3 a Protects underlying tissue from UV radiation a Protects against abrasion and serves as a water a A steroid that is converted to calcitriol b Calcitriol i A hormone that is important to normal calcium metabolism e Storage i Storage of lipids 1 2 In adipocytes in the dermis In adipose tissue in hypodermis f Detection i Detects touch pressure pain and temperature ii Relays this information to the nervous system 5 Describe the Epidermis a Composed of stratified squamous epithelium b Avascular i Nutrients and oxygen diffuse from capillaries in the dermis ii Cells with the highest metabolic demands are found close to the basement membrane where diffusion distance is short iii Superficial cells are dead c Dominated by keratinocytes i Keratinocytes 1 Most abundant type of epithelial cell 2 Contain large amounts of keratin protein a very strong fiber that causes skin to stick together d Thin Skin e Thick Skin i Covers most of the body ii FOUR layers of keratinocytes i Covers the palms of the hands and soles of the feet ii FIVE layers of keratinocytes has a stratum lucidum f Five Strata of Keratinocytes i Form basal lamina to free surface superior to inferior ii Stratum corneum iii Stratum lucidum iv Stratum granulosum v Stratum spinosum vi Stratum basale 6 Describe the major layers of skin What are the characteristics of each layer What are the components of each layer How are the layers different than each other a Stratum Basale i Attached to basement membrane by hemidesmosomes ii Forms a strong bond between epidermis and dermis iii Forms Epidermal Ridges basis of fingerprints iv Dermal Papillae tiny mounds Increase the area of basement membrane 1 2 Strengthen attachment between epidermis and dermis v Has many Basal Cells germinative cells 1 Dominate the stratum basale 2 Divisions replace superficial keratinocytes that are lost or shed at epithelial surface vi Specialized Cells 1 Merkel Cells a Found in hairless skin b Respond to touch trigger nervous system i Sensitive to touch ii When compressed release chemicals that stimulate sensory nerve endings a Contain the pigment melanin protects from UV 2 Melanocytes radiation b Scattered throughout stratum basale b Stratum Spinosum i The Spiny Layer ii Produced by division of stratum basale iii 8 10 layers of keratinocytes bound by desmosomes iv Cells shrink until cytoskeletons stick out spiny v Continue to divide increasing thickness of epithelium vi Contain dendritic Langerhans cells 1 Active in immune response 2 Stimulate Defense Against a Microorganisms that manage to penetrate superficial epidermal layers b Superficial skin cancers c Stratum Granulosum i The Grainy Layer ii Stops dividing starts producing iii Keratin iv Keratohyalin 1 A tough fibrous protein 2 Makes up hair and nails 1 Dense granules 2 Cross link keratin fibers v Functions 1 Produce protein fibers 2 Dehydrate and die 3 Create tightly interlocked layer of keratin surrounded d Stratum Lucidum by keratohyalin i The Clear Layer ii Found ONLY in thick skin iii Covers the stratum granulosum iv Cells here are flattened densely packed with keratin devoid of organelles e Stratum Corneum i The Horn Layer ii Exposed surface of skin iii All exposed skin surfaces except anterior of eyes undergo cornification keratinization 1 Keratinization Formations of protective superficial layers of cells filled with keratin 2 Cells are dead and linked together by desmosomes 3 Water resistant NOT waterproof 4 Shed and replaced every 2 weeks iv Takes 7 10 days for a cell to move from stratum basale to stratum corneum 7 How are fingerprints formed Why are they important a Ridge patterns on skin increases surface area and friction ensuring a secure grip 8 Explain the difference between insensible and sensible perspiration a Insensible Perspiration i Interstitial fluid lost by evaporation through the stratum corneum ii Lose about 500 mL or 1 pint of H2O per day iii NOT sweating normal evaporation b Sensible Perspiration i Water secreted by sweat glands c Dehydration i Causes 1 Damage to stratum corneum a Ex burns and blisters insensible perspiration 2 Immersion in hypertonic solution a Ex Sea Water osmosis dangerous for shipwreck survivors d Hydration i Osmosis ii Results from immersion in hypotonic solution 1 Ex Freshwater iii Causes swelling of epithelial cells evident on the palms and soles 9 Why do our fingers and toes get wrinkles when wet a Because epidermal cells will swell ridges wrinkles on finger tips b c Seems to be an involuntary reaction to water body s way to cause If you have nerve damage wrinkles won t form hands to be more adaptive to a watery environment so you can grasp things easier etc 10 Explain how carotene and melanin affect skin color What are the differences between these two pigments a Influences on Skin Color i Pigments Carotene and Melanin ii Blood circulation red blood cells b Carotene c Melanin i Orange yellow pigment ii Found in orange vegetables 1 Ex carrots squashes 2 Consume too much skin turns
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