1 / 145

An Introduction to Tissues

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. 4-1 Four Types of Tissue. Tissue

markpreston
Télécharger la présentation

An Introduction to Tissues

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 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

  2. 4-1 Four Types of Tissue • Tissue • Are collections of cells and cell products that perform specific, limited functions • Four types of tissue • Epithelial tissue • Connective tissue • Muscle tissue • Neural tissue

  3. 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

  4. 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

  5. 4-2 Epithelial Tissue • Epithelia • Layers of cells covering internal or external surfaces • Glands • Structures that produce secretions

  6. 4-2 Epithelial Tissue • Characteristics of Epithelia • Cellularity (cell junctions) • Polarity (apical and basal surfaces) • Attachment (basement membrane or basal lamina) • Avascularity • Regeneration

  7. Figure 4-1 The Polarity of Epithelial Cells Cilia Microvilli Apicalsurface Golgiapparatus Nucleus Mitochondria Basement membrane Basolateralsurfaces

  8. 4-2 Epithelial Tissue • Functions of Epithelial Tissue • Provide Physical Protection • Control Permeability • Provide Sensation • Produce Specialized Secretions (glandular epithelium)

  9. 4-2 Epithelial Tissue • Specializations of Epithelial Cells • Move fluids over the epithelium (protection) • Move fluids through the epithelium (permeability) • Produce secretions (protection and messengers) • Polarity • Apical surfaces • Microvilli increase absorption or secretion • Cilia (ciliated epithelium) move fluid • Basolateral surfaces

  10. 4-2 Epithelial Tissue • Maintaining the Integrity of Epithelia • Intercellular connections • Attachment to the basement membrane • Epithelial maintenance and repair

  11. 4-2 Epithelial Tissue • Intercellular Connections • Cell junctions • Form bonds with other cells or extracellular material • Tight junctions • Gap junctions • Desmosomes

  12. 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

  13. Figure 4-2a Cell Junctions Tight junction Adhesion belt Terminal web Spotdesmosome Gapjunctions Hemidesmosome This is a diagrammatic view of an epithelial cell,showing the major types of intercellularconnections.

  14. Figure 4-2b Cell Junctions Interlockingjunctionalproteins Tight junction Terminal web 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 betweenthe cells. A continuous adhesion belt lies deep to the tight junction. This belt is tied to the microfilaments of the terminal web.

  15. Figure 4-2c Cell Junctions Embedded proteins(connexons) Gap junctions permit the free diffusion of ions and small molecules between two cells.

  16. Figure 4-2d Cell Junctions Intermediatefilaments Cell adhesionmolecules (CAMs) Dense area Proteoglycans A spot desmosome tiesadjacent cells together.

  17. 4-2 Epithelial Tissue • Epithelial Maintenance and Repair • Epithelia are replaced by division of germinative cells (stem cells) • Near basement membrane

  18. 4-3 Classification of Epithelia • Singular = Epithelium; Plural = Epithelia • Classes of Epithelia • Based on shape • Squamous epithelia — thin and flat • Cuboidal epithelia — square shaped • Columnar epithelia — tall, slender rectangles • Based on layers • Simple epithelium — single layer of cells • Stratified epithelium — several layers of cells

  19. Table 4-1 Classifying Epithelia

  20. Table 4-1 Classifying Epithelia

  21. 4-3 Classification of Epithelia • Squamous Epithelia • Simple squamous epithelium • Absorption and diffusion • Mesothelium • Lines body cavities • Endothelium • Lines heart and blood vessels

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

  23. 4-3 Classification of Epithelia • Squamous Epithelia • Stratified squamous epithelium • Protects against attacks • Keratin protein adds strength and water resistance

  24. Figure 4-3b Squamous Epithelia Stratified Squamous Epithelium LOCATIONS: Surface of skin; lining of mouth, throat, esophagus, rectum, anus, and vagina FUNCTIONS: Provides physical protection against abrasion, pathogens, and chemical attack Squamoussuperficial cells Stem cells Basementmembrane Connectivetissue Surface of tongue LM  310

  25. 4-3 Classification of Epithelia • Cuboidal Epithelia • Simple cuboidal epithelium • Secretion and absorption • Stratified cuboidal epithelia • Sweat ducts and mammary ducts

  26. Figure 4-4a Cuboidal and Transitional Epithelia Simple Cuboidal Epithelium LOCATIONS: Glands; ducts;portions of kidney tubules; thyroidgland Connectivetissue FUNCTIONS: Limited protection,secretion, absorption Nucleus Cuboidalcells Basementmembrane Kidney tubule LM  650

  27. Figure 4-4b Cuboidal and Transitional Epithelia Stratified Cuboidal Epithelium LOCATIONS: Lining of some ducts(rare) FUNCTIONS: Protection, secretion,absorption Lumenof duct Stratifiedcuboidalcells Basementmembrane Nuclei Connectivetissue Sweat gland duct LM  500

  28. 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)

  29. Figure 4-4c Cuboidal and Transitional Epithelia Transitional Epithelium LOCATIONS: Urinarybladder; renal pelvis;ureters FUNCTIONS: Permitsexpansion and recoilafter stretching Epithelium(relaxed) Basement membrane Connective tissue andsmooth muscle layers LM  400 Empty bladder Epithelium(stretched) Basement membrane LM  400 Connective tissue andsmooth muscle layers LM  400 Full bladder Urinary bladder

  30. 4-3 Classification of Epithelia • Columnar Epithelia • Simple columnar epithelium • Absorption and secretion • Pseudostratified columnar epithelium • Cilia movement • Stratified columnar epithelium • Protection

  31. Figure 4-5a Columnar Epithelia Simple Columnar Epithelium LOCATIONS: Lining ofstomach, intestine, gallbladder,uterine tubes, and collectingducts of kidneys Microvilli Cytoplasm FUNCTIONS: Protection,secretion, absorption Nucleus Basementmembrane Looseconnective tissue LM  350 Intestinal lining

  32. Figure 4-5b Columnar Epithelia Pseudostratified Ciliated Columnar Epithelium LOCATIONS: Lining ofnasal cavity, trachea, andbronchi; portions of malereproductive tract Cilia Cytoplasm FUNCTIONS: Protection,secretion, move mucuswith cilia Nuclei Basementmembrane Looseconnective tissue Trachea LM  350

  33. Figure 4-5c Columnar Epithelia Stratified Columnar Epithelium LOCATIONS: Small areas ofthe pharynx, epiglottis, anus,mammary glands, salivarygland ducts, and urethra Looseconnective tissue Deeper basalcells FUNCTION: Protection Superficialcolumnar cells Lumen Lumen Cytoplasm Nuclei Basementmembrane Salivary gland duct LM  175

  34. 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

  35. 4-3 Classification of Epithelia • Glandular Epithelia • Modes of Secretion • Merocrine secretion • Apocrine secretion • Holocrine secretion

  36. 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

  37. 4-3 Classification of Epithelia Holocrine Secretion Released by cells bursting, killing gland cells Gland cells replaced by stem cells For example, sebaceous glands

  38. Figure 4-6 Modes of Glandular Secretion Secretoryvesicle Golgiapparatus Nucleus TEM  3039 Salivary gland Breaksdown Mammary gland Golgi apparatus Secretion Regrowth Hair Sebaceousgland Cells burst, releasingcytoplasmic contents Hair follicle Cells produce secretion,increasing in size Cell division replaceslost cells Stem cell

  39. 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

  40. 4-3 Classification of Epithelia • Glandular Epithelia • Gland Structure • Unicellularglands • Mucous (goblet) cells are the only unicellular exocrine glands • Scattered among epithelia • For example, in intestinal lining

  41. 4-3 Classification of Epithelia • Gland Structure • Multicellular glands • Structure of the duct • Simple (undivided) • Compound (divided) • Shape of secretory portion of the gland • Tubular (tube shaped) • Alveolar or acinar (blind pockets) • Relationship between ducts and glandular areas • Branched (several secretory areas sharing one duct)

  42. Figure 4-7 A Structural Classification of Exocrine Glands Duct SIMPLE GLANDS Glandcells SIMPLETUBULAR SIMPLE COILEDTUBULAR SIMPLE BRANCHEDTUBULAR Examples: Examples: Examples: • Gastric glands • Merocrine sweat • Intestinal glands • Mucous glands glands of esophagus,tongue, duodenum SIMPLE ALVEOLAR(ACINAR) SIMPLE BRANCHEDALVEOLAR Examples: Examples: • Not found in adult; a • Sebaceous (oil) stage in developmentof simple branchedglands glands

  43. Figure 4-7 A Structural Classification of Exocrine Glands COMPOUND GLANDS COMPOUND TUBULOALVEOLAR COMPOUNDTUBULAR COMPOUND ALVEOLAR(ACINAR) Examples: Examples: Examples: • Mucous glands (in mouth) • Salivary glands • Mammary glands • Bulbo-urethral glands (in • Glands of respiratory male reproductive system) passages • Testes (seminiferous • Pancreas tubules)

  44. 4-4 Connective Tissue • Characteristics of Connective Tissue • Specialized cells • Solid extracellular protein fibers • Fluid extracellular ground substance • The Extracellular Components of Connective Tissue (Fibers and Ground Substance) • Make up the matrix • Majority of tissue volume • Determinesspecialized function

  45. 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

  46. 4-4 Connective Tissue • Classification of Connective Tissues • Connective tissue proper • Connect and protect • Fluid connective tissues • Transport • Supporting connective tissues • Structural strength

  47. 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

  48. 4-4 Connective Tissue Connective Tissue Proper Cell Populations • Fibroblasts • Fibrocytes • Adipocytes • Mesenchymal cells • Macrophages • Mast cells • Lymphocytes • Microphages • Melanocytes

  49. 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

  50. 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.

More Related