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Tissues and tissue types

Tissues and tissue types. Tissues are: Collections of specialized cells and cell products organized to perform a limited number of functions Histology = study of tissues The four tissue types are: Epithelial Connective Muscular Nervous. Epithelial tissue. Includes glands and epithelium

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Tissues and tissue types

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  1. Tissues and tissue types • Tissues are: • Collections of specialized cells and cell products organized to perform a limited number of functions • Histology = study of tissues • The four tissue types are: • Epithelial • Connective • Muscular • Nervous

  2. Epithelial tissue • Includes glands and epithelium • Glands are secretory • Is avascular • Forms a protective barrier that regulates permeability • Cells may show polarity

  3. Functions of epithelium • Physical protection • Control permeability • Provide sensation • Produce specialized secretions

  4. Specializations of epithelium • Perform secretory functions • Perform transport functions • Maintain physical integrity • Ciliated epithelia move materials across their surface

  5. The Polarity of Epithelial Cells

  6. Maintaining the integrity of epithelium • Cells attach via cell adhesion molecules (CAM) • Cells attach at specialized cell junctions • Tight junctions • Desmosomes • Gap junctions

  7. Intercellular connections

  8. Structure of typical epithelium • Basal lamina attaches to underlying surface • Lamina lucida • Lamina densa • Germinative cells replace short-lived epithelial cells

  9. Classification of epithelia • Number of cell layers • Simple • Stratified • Shape of apical surface cells • Squamous • Cuboidal • Columnar

  10. Squamous Epithelia

  11. Cuboidal Epithelia

  12. Cuboidal Epithelia

  13. Transitional Epithelium

  14. Columnar Epithelia

  15. Columnar Epithelia

  16. Columnar Epithelia

  17. Glandular epithelia • Exocrine glands • Secrete through ducts onto the surface of the gland • Endocrine glands • Release hormones into surrounding fluid

  18. Glandular secretions can be: • Merocrine (product released through exocytosis) • Apocrine (involves the loss of both product and cytoplasm) • Holocrine (destroys the cell)

  19. Mechanisms of Glandular Secretion

  20. Glands • Unicellular • Individual secretory cells • Multicellular • Organs containing glandular epithelium • Classified according to structure

  21. A Structural Classification of Exocrine Glands

  22. Connective tissue functions: • Establishing a structural framework • Transporting fluids and dissolved materials • Protecting delicate organs • Supporting, surrounding and interconnecting tissues • Storing energy reserves • Defending the body from microorganisms

  23. A Classification of Connective Tissues

  24. Connective tissues contain • Specialized cells • Matrix • Composed of extracellular protein fibers and a ground substance

  25. Connective tissue proper • Contains varied cell populations • Contains various fiber types • A syrupy ground substance

  26. Fluid connective tissue • Contains a distinctive cell population • Watery ground substance with dissolved proteins • Two types • Blood • Lymph

  27. Supporting connective tissues • Less diverse cell population • Dense ground substance • Closely packed fibers • Two types • Cartilage • Bone

  28. Connective tissue proper • Contains fibers, a viscous ground substance, and a varied cell population • Fibroblasts • Macrophage • Adipocytes • Mesenchymal cells • Melanocytes • Mast cells • Lymphocytes • Microphages

  29. Connective tissue proper • Three types of fiber • Collagen fibers • Reticular fibers • Elastic fibers

  30. Connective tissue proper • Classified as loose or dense • Loose • Embryonic mesenchyme, mucous connective tissues • Areolar tissue • Adipose tissue • Reticular tissue • Dense • Dense regular CT • Dense irregular CT

  31. The Cells and Fibers of Connective Tissue Proper

  32. Connective Tissue in Embryos

  33. Adipose and Reticular Tissues

  34. Dense Connective Tissues

  35. Dense Connective Tissues

  36. Dense Connective Tissues

  37. Fluid connective tissues • Distinctive collections of cells in a fluid matrix • Blood • Formed elements and plasma • Red blood cells, white blood cells and platelets • Arteries carry blood away, veins carry to the heart • Capillaries allow diffusion into the interstitial fluid • Lymph • Interstitial fluid entering the lymphatic vessels

  38. Formed Elements of the Blood

  39. Supporting connective tissues • Cartilage and bone support the rest of the body • Cartilage • Grows via interstitial and appositional growth • Matrix is a firm gel containing chondroitin sulfate • Cells called chondrocytes • Cells found in lacunae • Perichondrium separates cartilage from surrounding tissues • Three types: hyaline, elastic and fibrocartilage

  40. The Perichondrium and Types of Cartilage

  41. The Perichondrium and Types of Cartilage

  42. The Perichondrium and Types of Cartilage

  43. Bone, or osseus tissue • Has osteocytes • Depend on diffusion through canaliculi for nutrients • Little ground substance • Dense mineralized matrix • Surrounded by periosteum

  44. Bone

  45. Membranes are simple organs • Form a barrier • Composed of epithelium and connective tissue • Four types • Cutaneous • Synovial • Serous • Mucous

  46. Membranes

  47. Mucous membranes • Line cavities that communicate with the exterior • Contain lamina propria

  48. Serous membranes • Line sealed internal cavities • Form transudate

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