Chapter 6 Bones and Skeletal Tissues

1. Chapter 6Bones and Skeletal Tissues Part A Skeletal Cartilages, Classification of Bones, and Functions of Bones

2. Without Bones We would look like Slugs

3. Skeletal Cartilages

4. Skeletal Cartilages • Cartilage tissue consists primarily of water • Accounts for its resilience (ability to spring back to its original shape after being compressed) • Contains no blood vessels or nerves • Surrounded by the perichondrium

5. Perichondrium • Surrounds skeletal cartilage • Made from dense irregular connective tissue • Resists outward expansion when cartilage is compressed • Contains blood vessels from which nutrients diffuse through matrix to reach cartilage cells • This limits cartilage thickness

6. Skeletal Cartilages • Three types of Skeletal Cartilages • Hyaline • Elastic • Fibrocartilage • All contain chondrocyte cells and an extracellular matrix of ground substance and fibers

7. Hyaline Cartilage • Looks like frosted glass when freshly exposed • Provides support, flexibility, and resilience • Is the most abundant skeletal cartilage • Contains fine collagen fibers

8. Hyaline Cartilage • Is present in these cartilages: • Articular – covers the ends of long bones • Costal – connects the ribs to the sternum • Respiratory – makes up the larynx and reinforces air passages • Nasal – supports the nose

9. Hyaline Cartilage in Blue Figure 6.1

10. Elastic Cartilage • Similar to hyaline cartilage but contains more elastic fibers • Better able to stand repeated bending

11. Elastic Cartilage • Found in the external ear and the epiglottis • Epiglottis is the flap that covers the opening of the larynx when we swallow

12. Elastic Cartilage in Green Figure 6.1

13. Fibrocartilage • Highly compressible with great tensile strength • Contains thick collagen fibers

14. Fibrocartilage • Found in sites subjected to both heavy pressure and stretch • menisci of the knee • intervertebral discs

15. Fibrocartilage in Red Figure 6.1

16. Growth of Cartilage • Cartilage grows in two ways • 1. Appositional – Growth from outside • cells in the perichondrium secrete matrix against the external face of existing cartilage

17. Growth of Cartilage • Cartilage grows in two ways • 2. Interstitial – Growth from inside • lacunae-bound chondrocytes inside the cartilage divide and secrete new matrix, expanding the cartilage from within

18. Growth of Cartilage • Typically cartilage growth ends during adolescence (same time as skeleton) • Calcification of cartilage occurs under certain conditions • During normal bone growth in youth • During old age

19. Growth of Cartilage • Calcified cartilage is not bone • Calcification is when calcium salts are deposited in the matrix and harden

20. Classification of Bones

22. Classification of Bones • Two basic types of bone tissue • Compact Bone • Homogeneous • Dense - looks smooth and solid to the naked eye

23. Classification of Bones • Two basic types of bone tissue • Spongy Bone • Honey comb of small needle-like pieces of bone • Many open spaces

24. Classification of Bones • The 206 named bones of the human skeleton are divided into two groups: • Axial skeleton • Appendicular skeleton

25. Axial Skeleton • Includes bones of the skull, vertebral column, and rib cage • Most involved in protecting, supporting, or carrying other body parts

26. Axial Skeleton in dark tan Figure 6.1

27. Appendicular Skeleton • Includes bones of the upper and lower limbs, shoulder, and hip

28. Appendicular Skeleton • Locomotion • Helps us move • Helps us manipulate our environment

29. Appendicular Skeletons in yellow Figure 6.1

30. Classification of Bonesby Shape • Long Bones • Short bones • Flat bones • Irregular bones

31. Long Bones • Longer than they are wide • Has a shaft with heads at both ends • Contains mostly compact bone Figure 6.2a

32. Long Bones • Examples of long bones • Humerus • Femur • The bones in your fingers Figure 6.2a

33. Short Bones • Contains mostly spongy bone • Cube shaped • Wrist and ankles • Carpals – Tarsals

34. Short Bones • Sesamoid bones • shaped like a sesame seed • Special bones that form within tendons • Example: Patella

35. Flat Bones • Thin & Flattened • Usually curved • Thin layers of compact bone around a layer of spongy bone Figure 6.2c

36. Flat Bones • Examples • Sternum • Ribs • Scapulae • most skull bones Figure 6.2c

37. Irregular Bones • Irregular shape • Bones with complicated shapes or ones that do not fit into other categories Figure 6.2d

38. Irregular Bones • Examples • vertebrae • hip bones Figure 6.2d

40. Functions of Bones

41. Function of Bones • Support • Protection • Movement • Mineral storage • Blood cell formation

42. Function of Bones • Support of the body • form the framework that supports the body and cradles soft organs • Protection of soft organs • provide a protective case for the brain, spinal cord, and vital organs • Movement due to attached skeletal muscles • provide levers for muscles

43. Function of Bones • Storage of minerals and fats • reservoir for minerals, especially calcium and phosphorus • Blood cell formation • hematopoiesis occurs within the marrow cavities of bones

44. Study Guide • You should be able to complete pages 120-122 of the study guide for the study guide check.

45. Quiz If you snooze, you lose. Next time!