1. Tissues: The living fabric Ch 4 c Membranes, Nervous, and Muscle Tissue

2. Membranes Cutaneous, Mucous, and Serous

3. Cutaneous, Mucous, and Serous Membranes Composed of epithelium tissue bound to connective tissue proper. Considered simple organs

4. Cutaneous Membranes Figure 4.9a Skin Exposed to air, considered a dry membrane

5. Cutaneous Membranes Figure 4.9a Consists of a keratinized stratified squamous epithelium (epidermis) firmly attached to a thick layer of dense irregular connective tissue (dermis)

6. Mucous Membranes Figure 4.9b Lines body cavities open to the exterior (digestive, respiratory, and urogenital tracts)

7. Mucous Membranes Figure 4.9b Epithelial tissue upon a layer of loose connective tissue, then sometimes smooth muscle

8. Mucous Membranes Figure 4.9b Considered Wet or moist membranes

9. Serous membranes Moist membranes found in closed ventral body cavities Simple squamous epithelium resting on a thin layer of loose connective areolar tissue

10. Serous membranes Serous fluid lubricates the facing surfaces of the parietal (wall) and visceral (organs). –Remember this is a double membrane with the serous fluid between the layers

11. Serous membranes Serous membranes named according to where they are and the organs they are associated with

12. Serous membranes Pleura – lining the thoracic wall and covering the lungs Pericardium – enclosing the heart Peritoneums – abdominopelvic cavity and visceral organs

13. Nervous Tissue

14. Consists of branched neurons with long cellular processes and supporting cells Supporting cells are nonconducting cells that support, insulate, and protect the delicate neurons.

15. Nervous Tissue Neurons transmits electrical signals from sensory receptors to effectors Found in the brain, spinal cord, and peripheral nerves

16. Nervous Tissue Figure 4.10

17. Muscle Tissue

18. Highly cellular Well-vascularized 3 types –Skeletal –Cardiac –smooth

19. Skeletal Muscle Long, cylindrical cells, also called muscle fibers Multinucleated with obvious striations (bands) Initiates and controls voluntary movement Found in skeletal muscles that attach to bones or skin

20. Skeletal muscle tissue Figure 4.11a Long, cylindrical, multinucleate cells with obvious striations Initiates and controls voluntary movement Found in skeletal muscles that attach to bones or skin

21. Cardiac Muscle Tissue Branching, striated, uninucleate cells interlocking at intercalated discs Propels blood into the circulation Found in the walls of the heart

22. Cardiac muscle Figure 4.11b Branching, striated, uninucleate cells interdigitating at intercalated discs Propels blood into the circulation Found in the walls of the heart

23. Smooth Muscle Tissue Sheets of spindle-shaped cells with central nuclei and no striations Propels substances along internal passageways (by peristalsis) Found in the walls of hollow organs

24. Smooth Muscle Tissue Figure 4.11c

25. Muscle Tissue Skeletal muscle is voluntary muscle Cardiac and Smooth muscles are involuntary muscles

26. What happens when there is trauma to tissue?

27. Tissue Trauma Causes inflammation, characterized by: –Dilation of blood vessels –Increase in vessel permeability –Redness, heat, swelling, and pain

28. Tissue Repair Figure 4.12a Severed blood vessels bleed Inflammatory chemicals are released

29. Tissue Repair Figure 4.12a Local blood vessels dilate and become more permeable This allows white blood cells and clotting proteins to invade injured site

30. Tissue Repair Figure 4.12a Clotting proteins initiate clotting, surface dries and forms a scab

31. Tissue Repair Figure 4.12b Granulation tissue is formed Capillary buds invade the clot, restoring vascular supply

32. Tissue Repair Figure 4.12b Fibroblasts secrete collagen, which bridges the gap Macrophages phagocytize dead and dying cell debris

33. Tissue Repair Figure 4.12b Surface epithelial cell divide and migrate over the granulation tissue

34. Tissue Repair Figure 4.12c About one week later, the fibrosed area (scar) has contracted and regeneration of the epithelium is in progress

35. Tissue Repair Figure 4.12c Results in a fully regenerated epithelium with underlying scar tissue

36. Regenerative Capacity Epithelial tissues, bone, areolar connective tissue, dense irregular connective tissue and blood- forming tissue regenerate extremely well

37. Regenerative Capacity Smooth muscle and dense regular connective tissue have a moderate capacity for regeneration

38. Regenerative Capacity Skeletal muscle and cartilage have a weak regenerative capacity

39. Regenerative Capacity Cardiac muscle and nervous tissue in the brain and spinal cord have NO functional regenerative capacity –They are replaced by scar tissue

40. Regenerative Capacity Scar tissue is strong, but lacks flexibility and elasticity of most normal tissues, nor can it perform the normal functions of the tissues it replaced

41. Developmental Aspects

42. Primary germ layers: ectoderm, mesoderm, and endoderm Figure 4.13

43. Developmental Aspects These three layers of cells are formed early in embryonic development then specialize to form the four primary tissues Figure 4.13

44. Developmental Aspects Nerve tissue arises from ectoderm (blue) Figure 4.13

45. Developmental Aspects Muscle and connective tissue arise from mesoderm (red) Figure 4.13

46. Developmental Aspects Most mucous membranes arise from endoderm (yellow) Figure 4.13

47. Developmental Aspects Epithelial tissues arise from all three germ layers Figure 4.13

48. Developmental Aspects By end of second month of development, all primary tissues have appeared Tissue cells remain mitotic and produce rapid growth until birth, except the division of nerve cells nearly stop during fetal period

49. Developmental Aspects After birth, most tissues divide until adult body size is achieved In adults only epithelia and blood- forming tissues are highly mitotic

50. Developmental Aspects With old age, the amount of collagen declines, making tissue repair less efficient With old age, bone, muscle, and nervous tissues begin to atrophy

51. Quiz Quiz next time Study guide check 16-21