1. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Chapter 4 Tissues

2. Body Tissues Slide 3.41 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  What are the characteristics of the different types of body tissues?

3. Body Tissues Slide 3.41 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Cells are specialized for particular functions  Tissues  Groups of cells with similar structure and function  Four primary types  Epithelium  Connective tissue  Nervous tissue  Muscle

4. © 2013 Pearson Education, Inc. Brain Spinal cord Nerves Nervous tissue: Internal communication Muscles attached to bones (skeletal) Muscles of heart (cardiac) Muscles of walls of hollow organs (smooth) Muscle tissue: Contracts to cause movement Epithelial tissue: Forms boundaries between different environments, protects, secretes, absorbs, filters Lining of digestive tract organs and other hollow organs Skin surface (epidermis) Bones Tendons Fat and other soft padding tissue Connective tissue: Supports, protects, binds other tissues together Figure 4.1 Overview of four basic tissue types: epithelial, connective, muscle, and nervous tissues.

5. © 2013 Pearson Education, Inc. Tissue is fixed Preserved Cut Sliced thin enough to transmit light or electrons Stained Enhances contrast Studying Human Tissue: Microscopy

6. © 2013 Pearson Education, Inc. Form boundaries Two main types (by location) Covering and lining epithelia On external and internal surfaces Glandular epithelia Secretory tissue in glands Epithelial Tissue (Epithelium)

7. Epithelial Tissues Slide 3.42 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Found in different areas  Body coverings  Body linings  Glandular tissue  Functions  Protection  Absorption  Filtration  Secretion

8. Epithelium Characteristics Slide 3.43 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Cells fit closely together  Always has one free surface (apical surface)  Lower surface is bound by a basement membrane (basal surface)  Avascular (no blood supply) but innervated by nerve fibers  Regenerate easily if well nourished  Most have microvilli, some have cilia

9. Classification of Epithelium Slide 3.44a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Number of cell layers  Simple – one layer  Stratified – more than one layer Figure 3.16a

10. Classification of Epithelium Slide 3.44b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Shape of cells  Squamous – flattened  Cuboidal – cube-shaped  Columnar – column-like Figure 3.16b

11. © 2013 Pearson Education, Inc. Gland One or more cells that makes and secretes an aqueous fluid called a secretion Classified by Site of product release—endocrine or exocrine Relative number of cells forming the gland unicellular (e.g., goblet cells) or multicellular Glandular Epithelia

12. © 2013 Pearson Education, Inc. Ductless glands Secretions not released into a duct Secrete (by exocytosis) hormones that travel through lymph or blood to their specific target organs Target organs respond in some characteristic way Endocrine Glands

13. © 2013 Pearson Education, Inc. Secretions released onto body surfaces (skin) or into body cavities More numerous than endocrine glands Secrete products into ducts Examples include mucous, sweat, oil, and salivary glands Exocrine Glands

14. © 2013 Pearson Education, Inc. The only important unicellular glands are mucous cells and goblet cells epithelial linings of intestinal and respiratory tracts All produce mucin Dissolves in water to form mucus Slimy protective, lubricating coating Unicellular Exocrine Glands

15. © 2013 Pearson Education, Inc. Microvilli Golgi apparatus Rough ER Nucleus Secretory vesicles containing mucin Figure 4.4 Goblet cell (unicellular exocrine gland).

16. © 2013 Pearson Education, Inc. Multicellular exocrine glands are composed of a duct and a secretory unit Usually surrounded by supportive connective tissue Supplies blood and nerve fibers Extends into and divides gland into lobes Multicellular Exocrine Glands

17. © 2013 Pearson Education, Inc. By structure and type of secretion Structure Simple glands (unbranched duct) or compound glands (branched duct) Type of secretion Merocrine – most – secrete products by exocytosis as produced Holocrine – accumulate products within then rupture Apocrine – accumulates products within but only apex ruptures – controversy if exist in humans Classification of Multicellular Glands

18. © 2013 Pearson Education, Inc. Simple duct structure (duct does not branch) Compound duct structure (duct branches) Tubular secretory structure Alveolar secretory structure Surface epitheliumDuctSecretory epithelium Simple tubular Example Intestinal glands Simple branched tubular Example Stomach (gastric) glands Compound tubular Example Duodenal glands of small intestine Simple alveolar Example No important example in humans Simple branched alveolar Example Sebaceous (oil) glands Compound tubuloalveolar Example Salivary glands Compound alveolar Example Mammary glands Figure 4.5 Types of multicellular exocrine glands.

19. © 2013 Pearson Education, Inc. Figure 4.6 Chief modes of secretion in human exocrine glands. Merocrine glands secrete their products by exocytosis. Secretory vesicles Secretory cell fragments In holocrine glands, the entire secretory cell ruptures, releasing secretions and dead cell fragments.

20. Connective Tissue Slide 3.53 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Found everywhere in the body  Includes the most abundant and widely distributed tissues  Functions  Binds body tissues together  Supports the body  Provides protection

21. Connective Tissue Characteristics Slide 3.54 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Variations in blood supply  Some tissue types are well vascularized  Some have poor blood supply or are avascular  Extracellular matrix  Non-living material that surrounds living cells

22. Connective Tissue Characteristics Slide 3.54 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Three characteristics make connective tissues different from other primary tissues 1.Have mesenchyme (an embryonic tissue) as their common tissue of origin 2.Have varying degrees of vascularity (blood vessels) 3.Have extracellular matrix  Connective tissue not composed mainly of cells  Largely nonliving extracellular matrix separates cells  So can bear weight, withstand tension, endure abuse

23. © 2013 Pearson Education, Inc. Three elements Ground substance Fibers Cells Composition and arrangement varies in different connective tissues Structural Elements of Connective Tissue

24. © 2013 Pearson Education, Inc. Unstructured material that fills space between cells Medium through which solutes diffuse between blood capillaries and cells Components Interstitial fluid Cell adhesion proteins ("glue" for attachment) Proteoglycans Protein core + large polysaccharides Trap water in varying amounts, affecting viscosity of ground substance Ground Substance

25. © 2013 Pearson Education, Inc. Three types of fibers provide support Collagen Strongest and most abundant type Tough; provides high tensile strength Elastic fibers Networks of long, thin, elastin fibers that allow for stretch and recoil Reticular Short, fine, highly branched collagenous fibers (different chemistry and form than collagen fibers) Branch, forming networks that offer more "give" Connective Tissue Fibers

26. © 2013 Pearson Education, Inc. "Blast" cells- Immature form; mitotically active; secrete ground substance and fibers Fibroblasts in connective tissue proper Chondroblasts in cartilage Osteoblasts in bone Hematopoietic stem cells in bone marrow (hemocytoblast) "Cyte" cells- Mature form; maintain matrix Chondrocytes in cartilage Osteocytes in bone Cells

27. © 2013 Pearson Education, Inc. Fat cells Store nutrients White blood cells Neutrophils, eosinophils, lymphocytes Tissue response to injury Mast cells Initiate local inflammatory response against foreign microorganisms they detect Macrophages Phagocytic cells that "eat" dead cells, microorganisms; function in immune system Other Cell Types: Connective Tissues

28. © 2013 Pearson Education, Inc. All connective tissues except bone, cartilage and blood Two subclasses Loose connective tissues Areolar, Adipose, Reticular Dense connective tissues (also called fibrous connective tissues) Dense regular, Dense irregular, Elastic Types of Connective Tissues: Connective Tissue Proper

29. Muscle Tissue Slide 3.64 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Function is to produce movement  Either locomotion of body or substances within body  Highly cellular  Well vascularized  Possess myofilaments (allow for contraction)

30. Muscle Tissue Slide 3.64 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Three types  Skeletal muscle  Cardiac muscle  Smooth muscle  Some are voluntary  Some have striations (banded appearance)

31. Nervous Tissue Slide 3.68 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Neurons and nerve support cells (neuroglia)  Function is to send impulses to other areas of the body  Irritability  Conductivity Figure 3.20

32. Cell Junctions How do cells bind together to form tissues?

33. Factors that bind cells to form a tissue Adhesive glycoproteins on plasma membrane surface Wavy indention that “fit” together

34. Membrane Junctions Some cells "free" e.g., blood cells, sperm cells Some bound into communities Tight junction Desmosome Gap junction

35. Tight junction Plasma membranes touch Protein molecules fuse together tightly Like zipper Prevent fluids and most molecules from moving between cells Where might these be useful in body? Small intestine

36. © 2013 Pearson Education, Inc. Plasma membranes of adjacent cells Microvilli Intercellular space Basement membrane Interlocking junctional proteins Intercellular space Tight junctions: Impermeable junctions prevent molecules from passing through the intercellular space. Figure 3.5a Cell junctions.

37. Desmosome Plasma membranes do not touch Keratin Filaments hold cells together “spot-weld” Give stability to cell Reduces possibility of tearing Allows for expansion Locations: areas subjected to great mechanical stress Skin, heart muscle, uterus

38. © 2013 Pearson Education, Inc. Intercellular space Linker proteins (cadherins) Intermediate filament (keratin) Plaque Desmosomes: Anchoring junctions bind adjacent cells together like a molecular “Velcro” and help form an internal tension-reducing network of fibers. Microvilli Intercellular space Basement membrane Plasma membranes of adjacent cells Figure 3.5b Cell junctions.

39. Gap Junction Plasma membranes are close but don’t touch Connexons (hollow cylinders) connect neighboring membranes Allows passage of ions, sugars, and other small molecules between cells Found between: Embryonic cells (vital to distribute nutrients before circulatory system) Cardiac muscle

40. © 2013 Pearson Education, Inc. Figure 3.5c Cell junctions. Plasma membranes of adjacent cells Microvilli Intercellular space Basement membrane Intercellular space Channel between cells (formed by connexons) Gap junctions: Communicating junctions allow ions and small molecules to pass for intercellular communication.

41. © 2013 Pearson Education, Inc. Composed of at least two primary tissue types An epithelium bound to underlying connective tissue proper Are simple organs Three types Cutaneous membranes Mucous membranes Serous membranes Covering and Lining Membranes

42. © 2013 Pearson Education, Inc. Skin Keratinized stratified squamous epithelium (epidermis) attached to a thick layer of connective tissue (dermis) Dry membrane Cutaneous Membranes

43. © 2013 Pearson Education, Inc. Cutaneous membrane The cutaneous membrane (the skin) covers the body surface. Cutaneous membrane (skin) Figure 4.11a Classes of membranes.

44. © 2013 Pearson Education, Inc. Mucosa indicates location not cell composition All called mucosae Line body cavities open to the exterior (e.g., Digestive, respiratory, urogenital tracts) Moist membranes bathed by secretions (or urine) Epithelial sheet lies over layer of connective tissue called lamina propria May secrete mucus Mucous Membranes

45. © 2013 Pearson Education, Inc. Mucous membranes Mucous membranes line body cavities that are open to the exterior. Mucosa of nasal cavity Mucosa of mouth Esophagus lining Mucosa of lung bronchi Figure 4.11b Classes of membranes.

46. © 2013 Pearson Education, Inc. Serosae—found in closed ventral body cavity Simple squamous epithelium (mesothelium) resting on thin areolar connective tissue Parietal serosae line internal body cavity walls Visceral serosae cover internal organs Serous fluid between layers Moist membranes Pleurae, pericardium, peritoneum Serous Membranes

47. © 2013 Pearson Education, Inc. Visceral peritoneum Parietal peritoneum Parietal pericardium Visceral pericardium Visceral pleura Parietal pleura Serous membranes line body cavities that are closed to the exterior. Serous membranes Figure 4.11c Classes of membranes.

48. Tissue Repair Slide 3.69 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  How are tissues repaired when injured?

49. Tissue Repair Slide 3.69 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Regeneration  Replacement of destroyed tissue by the same kind of cells  Fibrosis  Repair by dense fibrous connective tissue (scar tissue)  Determination of method  Type of tissue damaged  Severity of the injury

50. © 2013 Pearson Education, Inc. Necessary when barriers are penetrated Cells must divide and migrate Occurs in two major ways Regeneration Same kind of tissue replaces destroyed tissue Original function restored Fibrosis Connective tissue replaces destroyed tissue Original function lost Tissue Repair

51. © 2013 Pearson Education, Inc. Inflammation sets stage Release of inflammatory chemicals Dilation of blood vessels Increase in vessel permeability Clotting occurs Tissue Repair: Step 1

52. © 2013 Pearson Education, Inc. Figure 4.12. Tissue repair of a nonextensive skin wound: regeneration and fibrosis. Slide 1 Scab Blood clot in incised wound Epider mis Vein Inflammato ry chemicals Migrating white blood cell Artery Inflammation sets the stage: Severed blood vessels bleed. Inflammatory chemicals are released. Local blood vessels become more permeable, allowing white blood cells, fluid, clotting proteins, and other plasma proteins to seep into the injured area. Clotting occurs; surface dries and forms a scab. 1

53. © 2013 Pearson Education, Inc. Organization restores blood supply The blood clot is replaced with granulation tissue Epithelium begins to regenerate Fibroblasts produce collagen fibers to bridge the gap Debris is phagocytized Tissue Repair: Step 2

54. © 2013 Pearson Education, Inc. Slide 2 Figure 4.12. Tissue repair of a nonextensive skin wound: regeneration and fibrosis. Regenerating epithelium Area of granulation tissue ingrowth Macrophage Budding capillary Fibroblast Organization restores the blood supply: The clot is replaced by granulation tissue, which restores the vascular supply. Fibroblasts produce collagen fibers that bridge the gap. Macrophages phagocytize dead and dying cells and other debris. Surface epithelial cells multiply and migrate over the granulation tissue. 2

55. © 2013 Pearson Education, Inc. Regeneration and fibrosis The scab detaches Fibrous tissue matures; epithelium thickens and begins to resemble adjacent tissue Results in a fully regenerated epithelium with underlying scar tissue Tissue Repair: Step 3

56. © 2013 Pearson Education, Inc. Slide 3 Figure 4.12. Tissue repair of a nonextensive skin wound: regeneration and fibrosis. Regenerated epithelium Fibrosed area Regeneration and fibrosis effect permanent repair: The fibrosed area matures and contracts; the epithelium thickens. A fully regenerated epithelium with an underlying area of scar tissue results. 3

57. © 2013 Pearson Education, Inc. Regenerate extremely well Epithelial tissues, bone, areolar connective tissue, dense irregular connective tissue, blood-forming tissue Moderate regenerating capacity Smooth muscle and dense regular connective tissue Virtually no functional regenerative capacity Cardiac muscle and nervous tissue of brain and spinal cord New research shows cell division does occur Efforts underway to coax them to regenerate better Regenerative Capacity in Different Tissues

58. © 2013 Pearson Education, Inc. Primary germ layers Formed early in embryonic development Specialize to form the four primary tissues Superficial to deep: Ectoderm-Nerve tissue arises from ectoderm Mesoderm-Muscle and connective tissues arise from mesoderm Endoderm-Epithelial tissues arise from all three germ layers Developmental Aspects

59. © 2013 Pearson Education, Inc. Figure 4.13 Embryonic germ layers and the primary tissue types they produce. 16-day-old embryo (dorsal surface view) Epithelium (from all three germ layers) Ectoderm Mesoderm Endoderm Inner lining of digestive system (from endoderm) Nervous tissue (from ectoderm) Muscle and connec- tive tissue (mostly from mesoderm)

60. © 2013 Pearson Education, Inc. Normally function well through youth and middle age if adequate diet, circulation, and infrequent wounds and infections Epithelia thin with increasing age so more easily breached Tissue repair less efficient Bone, muscle and nervous tissues begin to atrophy DNA mutations possible  increased cancer risk Aging Tissues