Lecture 4: Chapter 4 The Tissue Level of Organization Pages: 106 - 152

1. Lecture 4: Chapter 4The Tissue Level of OrganizationPages: 106 - 152 Lecturer: Dr. Barjis Room: P313 Phone: (718) 260-5285 E-Mail: ibarjis@citytech.cuny.edu

2. Learning Objectives • Identify the four major tissue types and describe their functions. • Describe the relationship between form and function for each tissue type. • Discuss the types and functions of epithelial tissues. • Compare the structure and function of connective tissues.

3. Learning Objectives • Explain the structure and function of the four types of membrane. • Describe the three types of muscle tissue and the structural features of each. • Discuss the basic structure and role of neural tissue.

4. Tissues of the Body: An Introduction 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

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

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

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

8. The Polarity of Epithelial Cells

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

10. Intercellular connections Animation: check tutorials

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

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

13. Squamous Epithelia

14. Cuboidal Epithelia

15. Cuboidal Epithelia

16. Transitional Epithelium

17. Columnar Epithelia

18. Columnar Epithelia

19. Columnar Epithelia

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

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

22. Mechanisms of Glandular Secretion Animation: Mechanisms of glandular secretion(check tutorial)

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

24. A Structural Classification of Exocrine Glands

25. Connective Tissues 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

26. A Classification of Connective Tissues

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

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

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

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

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

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

33. 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

34. The Cells and Fibers of Connective Tissue Proper

35. Connective Tissue in Embryos

36. Adipose and Reticular Tissues

37. Dense Connective Tissues

38. Dense Connective Tissues

39. Dense Connective Tissues

40. 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

41. Formed Elements of the Blood

42. 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

43. The Perichondrium and Types of Cartilage

44. The Perichondrium and Types of Cartilage

45. The Perichondrium and Types of Cartilage

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

47. Bone

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

49. Membranes

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