The SKELETAL System

1. The SKELETAL System The framework of bones and cartilage which protect organs, and provides a lever system that allows locomotion.

2. Functions of the Skeletal System • Support • Protection • Movement Facilitation • Mineral Storage and Homeostasis • Hematopoiesis • Storage of Energy

3. Types of Bone Cells • Osteoblasts • Osteocytes • Osteoclasts

4. Bone Cells

5. Ossification/ Osteogenesis • the process by which bones form in the body – 2 types • Intramembranous Ossification • Membranes ----> Bone • Endochondral Ossification • Cartilage ----> Bone

6. Intramembranous Ossification

7. Endochondral Ossification

8. Homeostasis and Bone Remodeling • Bones are constantly undergoing ossification and remodeling • Replacing old bone matrix with new bone matrix • bone reabsorption (osteoclasts) • bone deposition (osteoblasts) • Allows injured or worn out bone to be replaced • Compact bone tissue is formed by the reorganization of spongy bone tissue

9. Long Bone Structure • Periosteum – the outer covering • Diaphysis - shaft of a long bone • Epiphysis - ends of a long bone • Medullary Cavity – contains marrow • Red Marrow – where blood cells are produced. • Yellow Marrow – where fat is stored • Articular Cartilage – thin layer of hyaline cartilage covering the epiphyses to reduce friction during movement. • Endosteum – thin layer of cells which line the medullary cavity.

10. Long Bone Structure

11. Classification of Bones • Compact Bone (Dense Bone) • little space between the solid components of bone • Spongy Bone (Trabecular Bone) • made up of an irregular network of thin plates of bone with many intercellular spaces called trabeculae (spicules) • spaces between trabeculae filled with red bone marrow- responsible for reducing weight of bone • responsible for hematopoiesis

12. Compact Bone

13. Compact Bone You Tube Video: Osteon Model found at http://www.youtube.com/watch?v=CQhUINnTdZI

14. Proximal End of a Long Bone

15. EpiphysealPlate

16. Spongy Bone Structure

17. Types of Bones • Long Bones • Short Bones • Flat Bones • Irregular Bones • Sesamoid Bones (not a classification used by all anatomists)

18. Types of Bones

19. Long Bones • Greater length than width • Have a distinct diaphysis and a variable number of epiphysis • Slightly curved for strength • Examples: humerus, ulna, radius, femur, tibia, fibula, metacarpals, metatarsals, phalanges

20. Short Bones • Cube-shaped bones • Nearly equal in length and width • Spongy texture on inside of the bone • Examples: carpal and tarsal bones

21. Flat Bones • Generally thin and flat • Compact bone on anterior and posterior surfaces with spongy bone in the middle • Provides protection to organs • Large surface area for muscle attachment • Examples: cranial bones, sternum, scapula, ribs

22. Irregular Bones • Complex shaped bones • Cannot be classified into other categories • Vary in the amount of spongy and compact bone • Examples: vertebrae, facial bones, patella

23. Bone Markings • Foramen - an opening or hole in a bone. Source: Mcstrother. (2010). File:Skull foramina labeled.svgWikimedia Commons. Retrieved on October 16, 2011 from http://en.wikipedia.org/wiki/File:Skull_foramina_labeled.svg.

24. Bone Markings • Meatus - a tube-like passageway within a bone Source: Pngnot. (2007). File:Gray908.png. Wikimedia Commons. Retrieved on October 16, 2011 from http://en.wikipedia.org/wiki/File:Gray908.png.

25. Bone Markings • Sinus - a space within a bone lined with mucus membrane that reduces the weight of a bone Source: Arcadian. (2007). File:Illu09 sinuses.jpg. Wikimedia Commons. Retrieved on October 16, 2011 from http://en.wikipedia.org/wiki/File:Illu09_sinuses.jpg

26. Bone Markings • Fossa - a depression or groove on a bone Source: Hughes, P. Shoulder Anatomy. Upper Limb Centre.Retrieved on October 16, 2011 from:http://www.upperlimbcentre.com/anatomy.htm Source: Uwe Gille. (2007). File:Scapula ant numbered.png.Wikimedia Commons. Retrieved on October 16, 2011 from:http://en.wikipedia.org/wiki/File:Scapula_ant_numbered.png

27. Bone Markings • Condyle - “Knuckle” - a large rounded prominence on a bone Source: Pngbot. (2007). File:SFile:Gray347.png.Wikimedia Commons. Retrieved on October 16, 2011 from:http://en.wikipedia.org/wiki/File:Gray347.png

28. Bone Markings • Tuberosity - an elevated, rounded, usually roughened area of a bone Source: Johnuniq. (2010). File: HumerusFront.png.Wikimedia Commons. Retrieved on October16, 2011 from http://en.wikipedia.org/wiki/File:HumerusFront.png

29. Bone Markings • Trochanter - a large blunt process found only on the femur Source: Pngbot. (2010). File:Gray343.png.Wikimedia Commons. Retrieved on October16, 2011 from http://en.wikipedia.org/wiki/File:Gray343.png

30. Bone Markings • Tubercle - a small rounded process Source: Bot. (2006). File:Gray122.png.Wikimedia Commons. Retrieved on October16, 2011 from http://en.wikipedia.org/wiki/File:Gray122.png.

31. Bone Markings • Process - any projection from the surface of abone Source: Engusz. (2007). File:Processusmastoideusossistemporalis.PNGWikimedia Commons. Retrieved on October16, 2011 from hhttp://en.wikipedia.org/wiki/File:Processusmastoideusossistemporalis.PNG

32. Suture and Fontanel • Sutures are the joints between the skull bones. They fuse together between the ages of 18 months old and 3 years. • Fontanels are the soft, membranous spots of a baby’s skull that allows for brain growth and the delivery of the fetus through the birth canal.

33. Divisions of the Skeleton • Axial Skeleton - bones that lie along the long axis of the body. Includes the skull, hyoid bone, sternum, ribs, and vertebrae. There are 80 bones. • Appendicular Skeleton - bones of the extremities. There are 126 bones.

34. Bones of the Skeletal System

35. Skull – Anterior View- Identify Bones

36. Skull – Lateral View- Identify Bones

37. Skull – Posterior View- Identify Bones

38. Skull You Tube Video: Skull Bones at http://www.youtube.com/watch?v=Nc5IRj3OJhE

39. Vertebrae • Bones of the vertebral column • Cervical vertebrae (7) - neck • Thoracic vertebrae (12) - ribs • Lumbar vertebrae (5) - lower back • Sacral vertebrae (5) - pelvic bones • Coccygeal vertebrae (4) - tail bone • Intervertebral Foramina - openings between the vertebrae for nerve exit

40. Vertebral Column

41. You Tube Video: Anatomy of the spinal http://www.youtube.com/watch?v=qigpRFN5o04&feature=related Anatomy of the spine

42. Joints (Articulations) The points of contact between bones, between bones and cartilage, or between teeth and bones.

43. Structural Classification of Joints • Classification of joints based upon how they are held together • Fibrous Joints • held together by fibrous connective tissue-skull sutures • Cartilaginous Joints • held together by cartilage-holds rib and sternum together • Synovial Joints • joint enclosed within a synovial or joint capsule- knee cap

44. Joints You Tube Video: Joints of the skeleton found at http://www.youtube.com/watch?v=VsBJ4oUff10&feature=related

45. Synovial Joints • Enclosed within a joint or synovial capsule • fibrous capsule - outer layer • attaches to periosteum of bone • synovial membrane - inner layer • secretes synovial fluid • Space between the ends of articulating bones called a synovial space • End of articulating bones are covered with hyaline (articular) cartilage

46. Typical Synovial Joint

47. Menisci • Pads of fibrocartilagenous discs found between bony surfaces in some joints • Allows the bones to fit together better • Maintains the stability of the joint • Absorbs shock • Directs the flow of synovial fluid to areas of greatest friction

48. Bursae • Sac-like structures that resemble joint capsules situated within body tissues • Function like ball-bearings • Reduces friction between bones and soft tissues • Reduces friction between bones and skin

49. Knee Joint

50. Shoulder Joint