1. Chapter 4 Tissues

2. Organization of Tissues Types There are four major tissue types: 1.Epithelium 2.Connective 3.Muscle 4.Nervous

3. Characteristics of Epithelial tissue High cellularity - lots of densely packed cells with … Specialized intercellular contacts - such as tight junctions, desmosomes and gap junctions. Basement membranes & other c.t. support - anchors to connective tissue. Polarity - it has an apical side and a basal side (a free edge and a fixed edge). Avascular - no blood supply. Receive oxygen and nutrients by diffusion Highly mitotic - cells readily regenerate.

4. Free Surface and Attached Surface Polarity: –apical and basolateral surfaces

5. Intercellular Connections Support and communication

6. Tight Junctions Between 2 cell membranes

7. Gap Junctions Allow rapid communications

8. Desmosomes CAMs, dense areas, and intercellular cement

9. Attachment to Basal Lamina Hemidesmosomes

10. Typical arrangement of epithelium

11. Subcategories of epithelial tissue i.Simple 1.squamous 2.cuboidal 3.columnar ii.Stratified 1.squamous 2.cuboidal 3.columnar iii.Special (doesn’t fall neatly into either of the above) 1.Pseudostratified columnar 2.Transitional

12. Classes of Epithelia

13. Figure 4–3a Simple Squamous Epithelium

14. Simple Squamous Top view Thyroid tissue Kidney

15. Stratified Squamous Epithelium

16. Stratified squamous

17. Keratinizing Stratified Squamous Keratin layer of dead cells

18. Simple Cuboidal Epithelium Figure 4–4a

19. Simple Cuboidal Nuclei Simple squamous cell

20. Stratified Cuboidal Epithelium Figure 4–4b

21. Stratified Cuboidal

22. Simple Columnar Epithelium

23. Simple Columnar Basement membrane Goblet cells

24. Stratified Columnar Epithelium

25. Stratified Columnar Rare, found in the male urethra and few other places. Stratified Columnar Basal layer Apical layer

26. Pseudostratified Columnar Epithelium

27. Pseudostratified columnar a.

28. Pseudostratified columnar b. Cilia

29. Transitional Epithelium

30. Transitional Found only in the urinary tract

31. Glandular Epithelium: exocrine glands

32. Modes of Secretion Merocrine secretion – sweat glands

33. Modes of Secretion Apocrine secretion – mammary glands

34. Modes of Secretion Holocrine secretion – sebaceous (oil) glands

35. Types of Secretions Serous glands: –watery secretions Mucous glands: –secrete mucins Mixed exocrine glands: –both serous and mucous

36. Unicellular Glands Goblet cells are the only unicellular exocrine glands: –scattered among epithelia –e.g., in intestinal lining

37. Structure of Multicellular Exocrine Glands Structural classes of exocrine glands Figure 4–7 (1 of 2)

38. Structure of Multicellular Exocrine Glands Figure 4–7 (2 of 2)

39. Characteristics of Connective Tissue Common developmental origin - it is all from mesoderm Mostly well vascularized (except cartilages, tendons and ligaments) Low cellularity - the general arrangement is a variable (often scant) number of cells in a non-living matrix. The matrix: fibers of protein (collagen, elastic & reticular) ground substance (proteoglycans, cell adhesion molecules & interstitial fluid

40. Connective tissue

41. Subcategories of Connective tissue i.Embryonic 1.Mesenchyme ii.Connective tissue proper 1.Loose a.Areolar b.Adipose c.Reticular 2.Dense a.Irregular (elastic or yellow) b.Regular (white fibrous) 3.Cartilage a.Hyaline b.Elastic c.Fibrocartilage 4.Bone (osseous) 5.Blood

42. Mesenchyme

43. Loose c.t.: areolar

44. Reticular Tissue Provides support Figure 4–10b

45. Loose c.t.: reticular

46. Adipose Tissue Contains many adipocytes (fat cells) Figure 4–10a

47. Loose c.t.: adipose

48. Types of Adipose Tissue White fat: –most common –stores fat –absorbs shocks –slows heat loss (insulation)

49. Types of Adipose Tissue Brown fat: –more vascularized –adipocytes have many mitochondria –breaks down fat –produces heat

50. Dense Regular Connective Tissue Attachment and stabilization

51. Dense regular c.t.

52. Dense regular c.t.: tendon

53. Dense Irregular Connective Tissue Strength in many directions Figure 4–11b

54. Dense irregular c.t.

55. More dense irregular c.t.

56. Elastic Tissue Made of elastic fibers: –e.g., elastic ligaments of spinal vertebrae

57. Cartilage Matrix Proteoglycans derived from chondroitin sulfates Ground substance proteins Cells (chondrocytes) surrounded by lacunae (chambers)

58. Cartilage Growth (1 of 2) Interstitial growth Figure 4–13a

59. Cartilage Growth (2 of 2) Appositional growth Figure 4–13b

60. Types of Cartilage Hyaline cartilage: –translucent matrix –no prominent fibers Elastic cartilage: –tightly packed elastic fibers Fibrocartilage: –very dense collagen fibers

61. Hyaline Cartilage Reduces friction in joints Figure 4–14a

62. Hyaline Cartilage

63. Elastic Cartilage Flexible support Figure 4–14b

64. Elastic Cartilage

65. Fibrocartilage Resists compression

67. Bone Also called osseous tissue: –strong (calcified: calcium salt deposits) –resists shattering (flexible collagen fibers)

68. Bone: compact

69. Bone

70. Fluid Connective Tissues Fluid connective tissues: –blood and lymph –watery matrix of dissolved proteins –carry specific cell types (formed elements)

71. Formed Elements of Blood Figure 4–12

72. Blood

73. 4 Types of Membranes 1.Mucous 2.Serous 3.Cutaneous 4.Synovial Figure 4–16

74. Mucous Membrane Mucous membranes (mucosae): –line passageways that have external connections –also in digestive, respiratory, urinary, and reproductive tracts

75. Structure of Mucous Membrane Figure 4–16a

76. Serous Membranes Line cavities not open to the outside Are thin but strong Have fluid transudate to reduce friction

77. Structure of Serous Membrane Figure 4–16b

78. Structure of Cutaneous Membrane

79. 3 Types of Fasciae Superficial fascia Figure 4–17

80. 3 Types of Fasciae Deep fascia Figure 4–17

81. 3 Types of Fasciae Subserous fascia Figure 4–17

82. Muscle tissue It contracts (shortens with force). It is irritable (responsive). There are three types 1.Skeletal 2.Smooth 3.Cardiac

83. Skeletal Muscle Most abundant Striated Multinucleate with peripheral nuclei Long, parallel fibers Voluntary

84. Skeletal Muscle Skeletal muscle l.sc.s.

85. Smooth Muscle Involuntary Not striated (hence the name “smooth”) Uninucleate Small, spindle-shaped fibers Found lining the walls of hollow organs

86. Skeletal Muscle Striated, voluntary, and multinucleated Figure 4–18a

87. Cardiac Muscle Striated Uninucleate (occasionally binucleate) Short, fat, branched fibers Intercalated discs Involuntary Found in the heart

88. Cardiac Muscle Tissue Striated, involuntary, and single nucleus Figure 4–18b

89. Cardiac muscle

90. Smooth Muscle Tissue Nonstriated, involuntary, and single nucleus Figure 4–18c

91. Smooth muscle

92. Neural Tissue Also called nervous or nerve tissue: –specialized for conducting electrical impulses –rapidly senses internal or external environment –process information and controls responses

93. 2 Kinds of Neural Cells 1.Neurons: –nerve cells –perform electrical communication 2.Neuroglia: –support cells –repair and supply nutrients to neurons

94. Neuroglia Figure 4–19

95. The Neuron Figure 4–19

96. Nervous tissue Neurons

97. That’s it!