1. Exercise 6 Classification of Tissues

2. What is a tissue? Groups of cells Groups of cells Similar in structure & function Similar in structure & function Tissues are further organized into organs (  organ systems) Tissues are further organized into organs (  organ systems)

3. 4 Major Tissue Types Epithelial Epithelial Connective Connective Muscle Muscle Nervous Nervous

4. Epithelial Tissues Cover surfaces Cover surfaces Simple or stratified? Simple or stratified? Simple = one layer of cells attached to the basement membrane Simple = one layer of cells attached to the basement membrane Stratified = two or more layers of cells Stratified = two or more layers of cells Name this epithelia by whichever “shape” the top layer of cells is (apical layer), not the bottom (basal layer) Name this epithelia by whichever “shape” the top layer of cells is (apical layer), not the bottom (basal layer)

5. Epithelial Tissues Shapes of Epithelial Cells Shapes of Epithelial Cells Squamous Squamous Scalelike, flattened Scalelike, flattened Cuboidal Cuboidal Cubelike Cubelike Columnar Columnar Column-shaped Column-shaped Simple squamous Stratified squamous Simple cuboidal Stratified cuboidal Simple columnar Stratified columnar

7. Epithelial Tissues Simple squamous epithelium Simple squamous epithelium

8. Epithelial Tissues Simple cuboidal epithelium Simple cuboidal epithelium Fig 4-4

9. Epithelial Tissues Simple columnar epithelium Simple columnar epithelium

10. Epithelial Tissues Pseudostratified columnar epithelium Pseudostratified columnar epithelium Actually simple columnar: nuclei are at different levels so there appears to be more than one layer Actually simple columnar: nuclei are at different levels so there appears to be more than one layer Fig 4-5

11. Epithelial Tissues Stratified squamous epithelium Stratified squamous epithelium

12. Epithelial Tissues Stratified cuboidal epithelium Stratified cuboidal epithelium

13. Epithelial Tissues Stratified columnar epithelium Stratified columnar epithelium Fig 4-5

14. Epithelial Tissues Fig 4-4 Transitional epithelium Transitional epithelium Stratified squamous epithelium formed of rounded cells that can slide over one another, allowing the organ to stretch: urinary system only Stratified squamous epithelium formed of rounded cells that can slide over one another, allowing the organ to stretch: urinary system only

15. CONNECTIVE TISSUES Embryonic connective tissue Embryonic connective tissue mesenchyme mesenchyme Loose connective tissue Loose connective tissue Areolar, adipose, reticular Areolar, adipose, reticular Dense connective tissue Dense connective tissue Dense irregular, dense regular Dense irregular, dense regular Supportive connective tissue Supportive connective tissue Hyaline, elastic, fibrocartilages; bone Hyaline, elastic, fibrocartilages; bone Fluid connective tissue Fluid connective tissue Blood, lymph Blood, lymph

16. CONNECTIVE TISSUES Differing proportions of cells and fibers to “matrix” Differing proportions of cells and fibers to “matrix” Matrix is noncellular, nonliving material between the connective tissue cells Matrix is noncellular, nonliving material between the connective tissue cells Different proportions have to deal with strength of the tissue Different proportions have to deal with strength of the tissue

17. Classification of Connective Tissues Fig. 4-8 Many cell types Syrupy ground substance Distinct cell types Watery matrix Less diverse cell types More fibrous matrix

18. Embryonic Connective Tissue Mesenchyme Mesenchyme Many star-shaped stem cells Gives rise to all other connective tissues Not present in adults Fig. 4-10

19. Loose Connective Tissue: Areolar

20. Loose Connective Tissue Adipose connective tissue Adipose connective tissue (fat) Insulation for the body’s tissues Food storage Little matrix Fig. 4-11

21. Loose Connective Tissue Reticular connective tissue Reticular connective tissue Reticular fibers form a soft internal skeleton for support

22. Dense Irregular Collagenous Connective Tissue

23. Dense Irregular Elastic

24. Dense Connective Tissue Dense regular connective tissue Dense regular connective tissue Fibers in one direction Tendons, ligaments of body’s joints Fig. 4-12

25. Dense Regular Elastic

26. Supportive Connective Tissue

27. Elastic Cartilage Elastic Cartilage Maintains shape, but flexible Many elastic fibers

28. Supportive Connective Tissue Fibrocartilage Fibrocartilage Strength, shock absorption Dense network of collagen fibers

29. Supportive Connective Tissue Osseous Connective Tissue (Bone) Osseous Connective Tissue (Bone) Support, protection

30. Fluid Connective Tissue

31. Lymph Lymph Fluid of the lymphatic system Like plasma without the big proteins Immune defense

32. MUSCLE TISSUES Skeletal Skeletal Cardiac Cardiac Smooth Smooth

33. Skeletal Muscle Tissue

34. Cardiac Muscle Tissue Only in the heart Only in the heart Striated tissue Striated tissue Under involuntary control Under involuntary control Branching, uninucleate cells with intercalated discs Branching, uninucleate cells with intercalated discs

35. Smooth Muscle Tissue Found in the walls of hollow organs (digestive, urinary tracts; blood vessels) Found in the walls of hollow organs (digestive, urinary tracts; blood vessels) 2 layers at right angles for contraction/dilation of the organ cavity Not striated tissue Uninucleate, spindle-shaped cells

36. Muscle typeCellsstriationsVoluntary? Cardiacbranched Uninucleate Intercalated discs yesno SkeletalLong fibers multinucleate yes SmoothSpindle shaped 1 nucleus no

37. NERVOUS TISSUE Brain, spinal cord, nerves Brain, spinal cord, nerves 2 basic cell types: 2 basic cell types: Neuroglia cells Protect, support, and insulate the neurons Neurons Receive stimuli and conduct nerve impulses all over the body