Integumentary System Notes

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Integumentary System Notes

  1. 1. Integumentary System Chapter 5
  2. 2. • Skin & Accessory organs: Hair & hair follicles sebaceous (oil) glands sudoriferous (sweat) glands nails
  3. 3. Functions of the Integumentary System 1. Protection: from exterior elements 2. Sensation: feeling 3. Excretion of wastes: sweat 4. Synthesis of Vitamin D in sunlight 5. Temperature regulation: release/retain heat 6. Coloration: pigment of skin 7. Water proof: water does not enter inside 8. Growth and repair: regenerate
  4. 4.  Skin structure 3 main layers 1. Epidermis:outer, thinner layer connected to the basement membrane 2. Dermis:inner, thicker layer 3. Hypodermis / subcutaneous layer (Sub Q): Under the dermis (adipose tissue)
  5. 5. List & Describe the 4 Cells in Epidermis  Found on pg. 152 in textbook  5 Minutes to locate & write…GO!
  6. 6. Cells of the Epidermis  Keratinocytes – produce the strong protein keratin.  Melanocytes – produce the brown pigment melanin  Langerhans’ cells –macrophages that help activate the immune system response  Merkel cells – function as touch receptors in association with sensory nerve endings
  7. 7. General Epidermis Info  Basement membrane= located right underneath the stratum basale and connects epidermis to the dermis
  8. 8. Layers of the Epidermis Figure 5.2b
  9. 9. Epidermis  outermost layer  Made of keratinized stratified squamous tissue, so it:  Lacks blood vessels  Is mostly dead  There are 5 distinct layers  MITOSIS does occur in bottom layers
  10. 10. 5 layers of the Epidermis  Pg 154 in textbook
  11. 11. Stratum basale  innermost layer  directly above the basement membrane  location • Merkel Cells • Melanocytes  Simple cuboidal  Cells undergo mitosis here
  12. 12. Stratum spinosum  composed of many layers of rounded cells with large nuclei  Langerhans’ cells are abundant in this layer
  13. 13. Stratum granulosum  composed of 3-5 layers of flattened granular cells  Cells start keratinization process here the process of cells formed in the stratum basale moving up, flattening, dying, and becoming hard and waterproof
  14. 14. Stratum lucidum  translucent layer  Not shown in book…why?  Because only located in thick skin of soles and palms
  15. 15. Stratum corneum  Top layer  composed of dead epithelial cells being flaked off (keratinized)  Functions include:  Waterproofing  Protection from abrasion and penetration
  16. 16. Dermis  inner layer  Much thicker than the epidermis  Dermis aka. “True Skin”  Contains nerve endings, muscle fibers, hair follicles, sudoriferous glands, sebaceous glands, and blood vessels.  Does not continually shed and regenerate itself
  17. 17. Dermis: 2 Layers 1. Papillary Layer  Arranged in ridges  The fingertips and toe tips  Ridges allow us to grip things
  18. 18. Dermis: 2 Layers…cont’d 2. Reticular Layer  Collagenous fibers: make our skin tough  Elastic fibers: make our skin stretchable.  Reticular fibers: gives skin its strength & resilience  Location of smooth muscle called arrector pili Stands hair on end when “goose bumps”
  19. 19. Subcutaneous layer or hypodermis  adipose tissue and blood vessels  beneath the dermis  Function – insulation
  20. 20. Cutaneous Sensation 1. Light touch detection: Meissner’s Corpuscles  located in dermal papillae of dermis
  21. 21. Cutaneous Sensation 2. Pressure detection = Pacinian Corpuscles  located deep in dermis and subcutaneous regions
  22. 22. Hair  Shaft: visible part of the hair  Medulla: inner core of the hair  Cuticle: layer covering medulla  Cortex: Superficial portion of hair  Root: in dermis
  23. 23. No need to know for test…  Just an Interesting FACT:  Straight hair has a rounded follicle  Wavy hair has a flattened follicle  Kinky or curly hair has a kidney shaped follicle
  24. 24. Are you ready to be grossed out?...................…
  25. 25. Eye Lash Mites
  26. 26. Skin Color  3 pigments contribute to skin color  Melanin – yellow to reddish-brown to black pigment, responsible for skin colors, related to genetics • Freckles and pigmented moles – result from local accumulations of melanin  Carotene – yellow to orange pigment  Hemoglobin – reddish pigment responsible for the pinkish hue of the skin
  27. 27. Pigment More about Melanin:  Is produced by melanocytes in stratum basale layer  People of different races have essentially the same # of melanocytes, but the amount of melanin produced varies
  28. 28.  The quantity of Melanin produced depends on 3 factors: 1. Heredity: MOST IMPORTANT • enzyme tyrosinase is absent at birth, then melanocytes are unable to produce melanin and a condition known as albinism is formed 2. Sunlight Exposure • Causes melanocytes to increase melanin production and darkening skin color 3. Hormones: ACTH (Adrenocorticotropic Hormone ) and MSH (melanin stimulating hormone) • Hypersecretion of either hormone may darken the skin
  29. 29. Albinism
  30. 30. Carotene
  31. 31. Hemoglobin
  32. 32. Nails cont’d…  Tightly packed hard, keratinized epidermal cells  Functions = manipulation and protection
  33. 33. Ripley’s Believe It or Not Lady
  34. 34. Sudoriferous Glands Two types 1. Eccrine  more common, mainly in forehead, palms, & soles. These function right at birth. - no odor in secretion Secretion = water plus salts and wastes (urea and uric acid) 2. Apocrine Mainly in armpits, groin, & breasts. Don’t function until puberty. These cause the “cold-sweat” during stress. -odor in secretion
  35. 35. Sebaceous Glands  -Connected to every hair follicle  -Secrete sebum (oil) into hair follicle Function – sebum keeps skin and hair soft Disorders  acne = overproduction of sebum – ducts clog and inflame
  36. 36. Ceruminous Glands  Associated with ears  Produces cerumen (earwax)

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