1. © 2012 Pearson Education, Inc. PowerPoint ® Lecture Presentations prepared by Jason LaPres Lone Star College—North Harris 4 The Tissue Level of Organization

2. © 2012 Pearson Education, Inc. An Introduction to Tissues Tissues Structures with discrete structural and functional properties Tissues in combination form organs, such as the heart or liver Organs can be grouped into 11 organ systems

3. © 2012 Pearson Education, Inc. 4-1 Four Types of Tissue Tissue Are collections of cells and cell products that perform specific, limited functions Four types of tissue 1.Epithelial tissue 2.Connective tissue 3.Muscle tissue 4.Neural tissue

4. © 2012 Pearson Education, Inc. 4-1 Four Types of Tissue Epithelial Tissue Covers exposed surfaces Lines internal passageways Forms glands Connective Tissue Fills internal spaces Supports other tissues Transports materials Stores energy

5. © 2012 Pearson Education, Inc. 4-1 Four Types of Tissue Muscle Tissue Specialized for contraction Skeletal muscle, heart muscle, and walls of hollow organs Neural Tissue Carries electrical signals from one part of the body to another

6. © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Epithelia Layers of cells covering internal or external surfaces Glands Structures that produce secretions

7. © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Characteristics of Epithelia Cellularity (cell junctions) Polarity (apical and basal surfaces) Attachment (basement membrane or basal lamina) Avascularity Regeneration

8. © 2012 Pearson Education, Inc. Figure 4-1 The Polarity of Epithelial Cells Cilia Microvilli Apical surface Golgi apparatus Nucleus Mitochondria Basement membrane Basolateral surfaces

9. © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Functions of Epithelial Tissue 1.Provide Physical Protection 2.Control Permeability 3.Provide Sensation 4.Produce Specialized Secretions (glandular epithelium)

10. © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Specializations of Epithelial Cells 1.Move fluids over the epithelium (protection) 2.Move fluids through the epithelium (permeability) 3.Produce secretions (protection and messengers) Polarity 1.Apical surfaces Microvilli increase absorption or secretion Cilia (ciliated epithelium) move fluid 2.Basolateral surfaces

11. © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Maintaining the Integrity of Epithelia 1.Intercellular connections 2.Attachment to the basement membrane 3.Epithelial maintenance and repair

12. © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Intercellular Connections Support and communication CAMs (cell adhesion molecules) Transmembrane proteins Intercellular cement Proteoglycans Hyaluronan (hyaluronic acid) Glycosaminoglycans

13. © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Intercellular Connections Cell junctions Form bonds with other cells or extracellular material 1.Tight junctions 2.Gap junctions 3.Desmosomes

14. © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Tight Junctions Between two plasma membranes Adhesion belt attaches to terminal web Prevents passage of water and solutes Isolates wastes in the lumen

15. © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Gap Junctions Allow rapid communication Are held together by channel proteins (junctional proteins, connexons) Allow ions to pass Coordinate contractions in heart muscle

16. © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Desmosomes CAMs, dense areas, and intercellular cement Spot desmosomes Tie cells together Allow bending and twisting Hemidesmosomes Attach cells to the basal lamina

17. © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Attachment to the Basement Membrane Clear layer (lamina lucida) Thin layer Secreted by epithelia Barrier to proteins Dense layer (lamina densa) Thick fibers Produced by connective tissue Strength and filtration

18. © 2012 Pearson Education, Inc. Figure 4-2 Cell Junctions Gap junctions Hemidesmosome Spot desmosome Clear layer Dense layer Intermediate filaments Basement membrane Dense area Embedded proteins (connexons) Proteoglycans Cell adhesion molecules (CAMs) Terminal web Adhesion belt Tight junction Interlocking junctional proteins Tight junction Adhesion belt

19. © 2012 Pearson Education, Inc. Figure 4-2a Cell Junctions This is a diagrammatic view of an epithelial cell, showing the major types of intercellular connections. Gap junctions Hemidesmosome Spot desmosome Terminal web Adhesion belt Tight junction

20. © 2012 Pearson Education, Inc. Figure 4-2b Cell Junctions Tight junction Adhesion belt A tight junction is formed by the fusion of the outer layers of two plasma membranes. Tight junctions prevent the diffusion of fluids and solutes between the cells. A continuous adhesion belt lies deep to the tight junction. This belt is tied to the microfilaments of the terminal web. Terminal web Interlocking junctional proteins

21. © 2012 Pearson Education, Inc. Figure 4-2c Cell Junctions Embedded proteins (connexons) Gap junctions permit the free diffusion of ions and small molecules between two cells.

22. © 2012 Pearson Education, Inc. Figure 4-2d Cell Junctions Intermediate filaments Dense area Cell adhesion molecules (CAMs) Proteoglycans A spot desmosome ties adjacent cells together.

23. © 2012 Pearson Education, Inc. Figure 4-2e Cell Junctions Clear layer Dense layer Hemidesmosomes attach a cell to extracellular structures, such as the protein fibers in the basement membrane. Basement membrane

24. © 2012 Pearson Education, Inc. 4-2 Epithelial Tissue Epithelial Maintenance and Repair Epithelia are replaced by division of germinative cells (stem cells) Near basement membrane

25. © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Singular = Epithelium; Plural = Epithelia Classes of Epithelia 1.Based on shape Squamous epithelia — thin and flat Cuboidal epithelia — square shaped Columnar epithelia — tall, slender rectangles 2.Based on layers Simple epithelium — single layer of cells Stratified epithelium — several layers of cells

26. © 2012 Pearson Education, Inc. Table 4-1 Classifying Epithelia

27. © 2012 Pearson Education, Inc. Table 4-1 Classifying Epithelia

28. © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Squamous Epithelia Simple squamous epithelium Absorption and diffusion Mesothelium Lines body cavities Endothelium Lines heart and blood vessels

29. © 2012 Pearson Education, Inc. Figure 4-3a Squamous Epithelia Simple Squamous Epithelium Lining of peritoneal cavity Connective tissue Nucleus Cytoplasm LOCATIONS: Mesothelia lining ventral body cavities; endothelia lining heart and blood vessels; portions of kidney tubules (thin sections of nephron loops); inner lining of cornea; alveoli of lungs FUNCTIONS: Reduces friction; controls vessel permeability; performs absorption and secretion LM  238

30. © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Squamous Epithelia Stratified squamous epithelium Protects against attacks Keratin protein adds strength and water resistance

31. © 2012 Pearson Education, Inc. Figure 4-3b Squamous Epithelia LOCATIONS: Surface of skin; lining of mouth, throat, esophagus, rectum, anus, and vagina FUNCTIONS: Provides physical protection against abrasion, pathogens, and chemical attack Surface of tongue Squamous superficial cells Stem cells Basement membrane Connective tissue LM  310 Stratified Squamous Epithelium

32. © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Cuboidal Epithelia Simple cuboidal epithelium Secretion and absorption Stratified cuboidal epithelia Sweat ducts and mammary ducts

33. © 2012 Pearson Education, Inc. Figure 4-4a Cuboidal and Transitional Epithelia Simple Cuboidal Epithelium LOCATIONS: Glands; ducts; portions of kidney tubules; thyroid gland FUNCTIONS: Limited protection, secretion, absorption Kidney tubule Connective tissue Nucleus Cuboidal cells Basement membrane LM  650

34. © 2012 Pearson Education, Inc. Figure 4-4b Cuboidal and Transitional Epithelia LOCATIONS: Lining of some ducts (rare) FUNCTIONS: Protection, secretion, absorption LM  500 Lumen of duct Sweat gland duct Stratified cuboidal cells Basement membrane Nuclei Connective tissue Stratified Cuboidal Epithelium

35. © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Transitional Epithelium Tolerates repeated cycles of stretching and recoiling and returns to its previous shape without damage Appearance changes as stretching occurs Situated in regions of the urinary system (e.g., urinary bladder)

36. © 2012 Pearson Education, Inc. Figure 4-4c Cuboidal and Transitional Epithelia Transitional Epithelium FUNCTIONS: Permits expansion and recoil after stretching LOCATIONS: Urinary bladder; renal pelvis; ureters LM  400 Urinary bladder LM  400 Empty bladder Epithelium (relaxed) Connective tissue and smooth muscle layers Epithelium (stretched) Connective tissue and smooth muscle layers Basement membrane Full bladder Basement membrane LM  400

37. © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Columnar Epithelia Simple columnar epithelium Absorption and secretion Pseudostratified columnar epithelium Cilia movement Stratified columnar epithelium Protection

38. © 2012 Pearson Education, Inc. Figure 4-5a Columnar Epithelia LOCATIONS: Lining of stomach, intestine, gallbladder, uterine tubes, and collecting ducts of kidneys FUNCTIONS: Protection, secretion, absorption Simple Columnar Epithelium Microvilli Cytoplasm Intestinal lining Basement membrane Loose connective tissue LM  350 Nucleus

39. © 2012 Pearson Education, Inc. Figure 4-5b Columnar Epithelia LOCATIONS: Lining of nasal cavity, trachea, and bronchi; portions of male reproductive tract FUNCTIONS: Protection, secretion, move mucus with cilia Pseudostratified Ciliated Columnar Epithelium Cilia Trachea Cytoplasm Nuclei Basement membrane Loose connective tissue LM  350

40. © 2012 Pearson Education, Inc. Figure 4-5c Columnar Epithelia LOCATIONS: Small areas of the pharynx, epiglottis, anus, mammary glands, salivary gland ducts, and urethra FUNCTION: Protection Stratified Columnar Epithelium Salivary gland duct Deeper basal cells Loose connective tissue Superficial columnar cells Cytoplasm Nuclei Basement membrane Lumen LM  175

41. © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Glandular Epithelia Endocrine glands Release hormones Into interstitial fluid No ducts Exocrine glands Produce secretions Onto epithelial surfaces Through ducts

42. © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Glandular Epithelia Modes of Secretion 1.Merocrine secretion 2.Apocrine secretion 3.Holocrine secretion

43. © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Merocrine Secretion Produced in Golgi apparatus Released by vesicles (exocytosis) For example, sweat glands Apocrine Secretion Produced in Golgi apparatus Released by shedding cytoplasm For example, mammary glands

44. © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Holocrine Secretion Released by cells bursting, killing gland cells Gland cells replaced by stem cells For example, sebaceous glands

45. © 2012 Pearson Education, Inc. Figure 4-6 Modes of Glandular Secretion Salivary gland Mammary gland Hair Sebaceous gland Hair follicle Stem cell Cell division replaces lost cells Cells produce secretion, increasing in size Cells burst, releasing cytoplasmic contents Secretion Regrowth Golgi apparatus Breaks down Secretory vesicle Golgi apparatus Nucleus TEM  3039

46. © 2012 Pearson Education, Inc. Figure 4-6a Modes of Glandular Secretion Salivary gland Mammary gland Hair Sebaceous gland Hair follicle Merocrine. In merocrine secretion, secretory vesicles are discharged at the apical surface of the gland cell by exocytosis. Secretory vesicle Golgi apparatus Nucleus TEM  3039

47. © 2012 Pearson Education, Inc. Figure 4-6b Modes of Glandular Secretion Salivary gland Mammary gland Hair Sebaceous gland Hair follicle Apocrine. Apocrine secretion involves the loss of apical cytoplasm. Inclusions, secretory vesicles, and other cytoplasmic components are shed in the process. The gland cell then undergoes growth and repair before it releases additional secretions. Secretion Regrowth Golgi apparatus Breaks down

48. © 2012 Pearson Education, Inc. Figure 4-6c Modes of Glandular Secretion Salivary gland Mammary gland Hair Sebaceous gland Hair follicle Stem cell Holocrine. Holocrine secretion occurs as superficial gland cells burst. Continued secretion involves the replacement of these cells through the mitotic division of underlying stem cells. Cell division replaces lost cells Cells produce secretion, increasing in size Cells burst, releasing cytoplasmic contents

49. © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Glandular Epithelia Types of Secretions Serous glands Watery secretions Mucous glands Secrete mucins Mixed exocrine glands Both serous and mucous

50. © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Glandular Epithelia Gland Structure Unicellular glands Mucous (goblet) cells are the only unicellular exocrine glands Scattered among epithelia For example, in intestinal lining

51. © 2012 Pearson Education, Inc. 4-3 Classification of Epithelia Gland Structure Multicellular glands 1.Structure of the duct Simple (undivided) Compound (divided) 2.Shape of secretory portion of the gland Tubular (tube shaped) Alveolar or acinar (blind pockets) 3.Relationship between ducts and glandular areas Branched (several secretory areas sharing one duct)

52. © 2012 Pearson Education, Inc. Figure 4-7 A Structural Classification of Exocrine Glands SIMPLE GLANDS Gland cells SIMPLE TUBULAR SIMPLE COILED TUBULAR Examples: Intestinal glands Merocrine sweat stage in development of simple branched glands SIMPLE BRANCHED TUBULAR Examples: Gastric glands Mucous glands Not found in adult; a SIMPLE ALVEOLAR (ACINAR) SIMPLE BRANCHED ALVEOLAR Examples: Sebaceous (oil) glands of esophagus, tongue, duodenum glands Duct

53. © 2012 Pearson Education, Inc. Figure 4-7 A Structural Classification of Exocrine Glands COMPOUND GLANDS COMPOUND TUBULAR COMPOUND ALVEOLAR (ACINAR) COMPOUND TUBULOALVEOLAR Examples: Mucous glands (in mouth) Examples: Bulbo-urethral glands (in male reproductive system) tubules) Mammary glands Examples: Salivary glands Glands of respiratory passages Testes (seminiferous Pancreas

54. © 2012 Pearson Education, Inc. 4-4 Connective Tissue Characteristics of Connective Tissue 1.Specialized cells 2.Solid extracellular protein fibers 3.Fluid extracellular ground substance The Extracellular Components of Connective Tissue (Fibers and Ground Substance) Make up the matrix Majority of tissue volume Determines specialized function

55. © 2012 Pearson Education, Inc. 4-4 Connective Tissue Functions of Connective Tissue Establishing a structural framework for the body Transporting fluids and dissolved materials Protecting delicate organs Supporting, surrounding, and interconnecting other types of tissue Storing energy reserves, especially in the form of triglycerides Defending the body from invading microorganisms

56. © 2012 Pearson Education, Inc. 4-4 Connective Tissue Classification of Connective Tissues 1.Connective tissue proper Connect and protect 2.Fluid connective tissues Transport 3.Supporting connective tissues Structural strength

57. © 2012 Pearson Education, Inc. 4-4 Connective Tissue Categories of Connective Tissue Proper Loose connective tissue More ground substance, fewer fibers For example, fat (adipose tissue) Dense connective tissue More fibers, less ground substance For example, tendons

58. © 2012 Pearson Education, Inc. 4-4 Connective Tissue Fibroblasts Fibrocytes Adipocytes Mesenchymal cells Macrophages Mast cells Lymphocytes Microphages Melanocytes Connective Tissue Proper Cell Populations

59. © 2012 Pearson Education, Inc. 4-4 Connective Tissue Fibroblasts The most abundant cell type Found in all connective tissue proper Secrete proteins and hyaluronan (cellular cement) Fibrocytes The second most abundant cell type Found in all connective tissue proper Maintain the fibers of connective tissue proper

60. © 2012 Pearson Education, Inc. 4-4 Connective Tissue Adipocytes Fat cells Each cell stores a single, large fat droplet Mesenchymal Cells Stem cells that respond to injury or infection Differentiate into fibroblasts, macrophages, etc.

61. © 2012 Pearson Education, Inc. 4-4 Connective Tissue Macrophages Large, amoeba-like cells of the immune system Eat pathogens and damaged cells Fixed macrophages stay in tissue Free macrophages migrate

62. © 2012 Pearson Education, Inc. 4-4 Connective Tissue Mast Cells Stimulate inflammation after injury or infection Release histamine and heparin Basophils are leukocytes (white blood cells) that also contain histamine and heparin

63. © 2012 Pearson Education, Inc. 4-4 Connective Tissue Lymphocytes Specialized immune cells in lymphatic (lymphoid) system For example, lymphocytes may develop into plasma cells (plasmocytes) that produce antibodies

64. © 2012 Pearson Education, Inc. 4-4 Connective Tissue Microphages Phagocytic blood cells Respond to signals from macrophages and mast cells For example, neutrophils and eosinophils Melanocytes Synthesize and store the brown pigment melanin

65. © 2012 Pearson Education, Inc. 4-4 Connective Tissue Connective Tissue Fibers 1.Collagen fibers 2.Reticular fibers 3.Elastic fibers

66. © 2012 Pearson Education, Inc. 4-4 Connective Tissue Collagen Fibers Most common fibers in connective tissue proper Long, straight, and unbranched Strong and flexible Resist force in one direction For example, tendons and ligaments

67. © 2012 Pearson Education, Inc. 4-4 Connective Tissue Reticular Fibers Network of interwoven fibers (stroma) Strong and flexible Resist force in many directions Stabilize functional cells (parenchyma) and structures For example, sheaths around organs

68. © 2012 Pearson Education, Inc. 4-4 Connective Tissue Elastic Fibers Contain elastin Branched and wavy Return to original length after stretching For example, elastic ligaments of vertebrae

69. © 2012 Pearson Education, Inc. 4-4 Connective Tissue Ground Substance Is clear, colorless, and viscous Fills spaces between cells and slows pathogen movement

70. © 2012 Pearson Education, Inc. Figure 4-8 The Cells and Fibers of Connective Tissue Proper Reticular fibers Melanocyte Fixed macrophage Plasma cell Blood in vessel Adipocytes (fat cells) Ground substance Mast cell Elastic fibers Free macrophage Collagen fibers Fibroblast Mesenchymal cell Lymphocyte

71. © 2012 Pearson Education, Inc. Figure 4-8 The Cells and Fibers of Connective Tissue Proper Elastic fibers Collagen fibers Fibroblast Free macrophage Connective tissue proper LM  502

72. © 2012 Pearson Education, Inc. 4-4 Connective Tissue Embryonic Connective Tissues Are not found in adults Mesenchyme (embryonic stem cells) The first connective tissue in embryos Mucous connective tissue Loose embryonic connective tissue

73. © 2012 Pearson Education, Inc. Figure 4-9a Connective Tissues in Embryos Mesenchymal cells Mesenchyme This is the first connective tissue to appear in an embryo. LM  136

74. © 2012 Pearson Education, Inc. Figure 4-9b Connective Tissues in Embryos Mesenchymal cells Blood vessel Mucous connective tissue (Wharton’s jelly) LM  136 This sample was taken from the umbilical cord of a fetus.

75. © 2012 Pearson Education, Inc. 4-4 Connective Tissue Loose Connective Tissues The “packing materials” of the body Three types in adults 1.Areolar 2.Adipose 3.Reticular