1. Integumentary System

2. Integumentary System Epidermis (epithelial tissue)
Dermis (connective tissue)
Hypodermis (not part of the skin)

5. Hypodermis
subcutaneous layer (underneath the skin)

6. Hypodermis
contains areolar and adipose tissue

7. Hypodermis
attaches skin to underlying tissues and organs

8. Hypodermis
Conatains pacinian corpuscles ( sensitive to pressure / looks like an onion)

9. Epidermis Stratified Squamous epithelium 4 different types of cells
5 layers

10. Types of Cells in Epidermis
Keratinocytes
Melanocytes
Langerhans
Merkel

11. Keratinocytes
90% of epidermal cells

12. Keratinocytes
produce the protein keratin which protects the skin and underlying tissues from heat, microbes, and chemicals

13. Keratinocytes
produce lamellar granules which produce a water repellant sealant

14. Melanocytes
8 % of epidermal cells

15. Melanocytes
Produces the pigment melanin

16. Melanocytes
Transfers melanin granules to keratinocytes

17. Melanocytes
In keratinocytes the melanin granules acts like an umbrella over the DNA in order to protect it from UV light

18. Langerhans
migrate from red bone marrow to epidermis

19. Langerhans
involved in immune response

20. Merkel
sensitive to touch

21. Merkel
located in stratum basale

22. Merkel
Have contact with the flattened process of a sensory neuron (Merkel disc)

23. 5 layers of Epidermis Stratum Basale Stratum Spinosum
Stratum Granulosum
Stratum Lucidum
Stratum Corneum

24. Stratum Basale
Deepest layer of the epidermis

26. Stratum Basale
Single layer of cuboidal or columnar keratinocytes

28. Stratum Basale
Nuclei large

29. Stratum Basale
Also contains some melanocytes, merkel cells, and langerhans cells

30. Stratum Spinosum
8 to 10 layers of squamous shaped keratinocytes

32. Stratum Spinosum
Has a large nucleus

33. Stratum Spinosum
Appear spiny underneath microscope

34. Stratum Spinosum
Some langerhans cells and melanocytes

35. Stratum Granulosum
3 to five layer of squamous keratinocytes

37. Stratum Granulosum
Undergoing apoptosis (cell death)

38. Stratum Granulosum
Nuclei disappearing

39. Stratum Granulosum
Contains protein keratohyalin which converts tonofilaments into keratin

40. Stratum Granulosum
Secretes lamellar granules which fills the spaces between stratum granulousum, stratum lucidum, and stratum corneum

41. Stratum Lucidum
Only in thick skin

43. Stratum Lucidum
3 to 5 layers of clear, dead, squamous keratinocytes

44. Stratum Lucidum
Contain keratin

45. Stratum Corneum
25 to 30 layers

47. Stratum Corneum
Dead squamous keratinocytes

48. Stratum Corneum
Contain keratin

49. Stratum Corneum
Sometimes forms callus (the stratum corneum is abnormally thick)

50. Dermis
Two Regions
Papillary Region
Reticular Region

51. Papillary Region
Contains areolar connective tissue with fine elastic fibers

53. Papillary Region
20 percent or one fifth of dermis

54. Papillary Region
Contains Meisner corpuscles ( sensitive to touch)

55. Papillary Region
Contains dermal papillae (small,fingerlike projections that indent the epidermis and some contain capillary loops)

57. Reticular Region
Contains dense irregular connective tissue with collagen fibers and course elastic fibers

58. Reticular Region
Contain some adipocytes, hair follicles, nerves, sebaceous glands, and sweat glands

61. Skin Color
Melanin
Carotene
Hemoglobin

62. Melanin
Number of melanocytes doesn’t vary among people

63. Melanin
Differences in skin color can be attributed to the amount that these melanocytes produce

64. Melanin
Melanocytes most commonly found in the epidermis of the penis, nipples, face and limbs

65. Melanin
Freckles and age spot (accumulations of melanin)

66. Carotene
Yellow-orange pigment
Precursor to vitamin A

67. Carotene
Found in stratum corneum, fatty areas of dermis, and hypodermis

68. Hemoglobin Protein in rbc’s that carries oxygen
Found in capillaries in blood

69. Albinos Contain melanocytes, but are unable to produce melanin
Inherited
Melanin is absent in hair, eyes, and skin

70. Vitiligo Irregular white spots Due to loss of melanocytes
Antibodies in body attack melanocytes

71. Types of Skin
Thin Skin
Thick Skin

72. Thin Skin
Covers all surfaces except palms, fingertips, and soles

74. Thin Skin
Lacks stratum lucidum
Thin stratum spinosum and corneum

75. Thin Skin
Lack epidermal ridges (fingerprints)

76. Thin Skin
Fewer sweat glands
Fewer sensory receptors

77. Thin Skin
Contains hair follicles, arrector pili muscles, and sebaceous (oil) gland

79. Thick Skin
Located on palms, fingertips, and soles

81. Thick Skin
Stratum Lucidum
Thicker stratum spinosum and corneum

82. Thick Skin
Contains epidermal ridges
Contains more sweat glands

83. Thick Skin
Lacks hair follicles, sebaceous glands, and arector pili muscles

84. Accessory Structures
Hair
Glands
Nails

85. Hair
Shaft
Superficial portion of hair

86. Hair
Root
Penetrates into dermis

87. Hair Root and Shaft contain three layers
Inner medulla(may lack in thin hair), cortex (contains pigment granules), and cuticle

88. Hair Hair Follicle Surrounds the root of the hair
Contains an external root sheath (continuation of epidermis) and internal root sheath (produced by the matrix)

89. Hair
Bulb
Contains papilla of hair (areolar connective tissue and blood vessels to nourish hair)
Contains matrix (produce new hairs)

92. Hair
Sebaceous glands and arrector pili muscle associated with hairs

93. Hair
Arrector pili muscle responsible for “goose bumps”