1. Skeletal System Chp. 5

2. Recall that connective tissue consists of a matrix with cells suspended w/in it--the type of matrix & cells determine type of tissue. 1.Bones - hard elements of skeleton. 2.Ligaments - dense, fibrous connective tissue that serves to bind bone-to-bone. 3.Cartilage - collagen & elastin fibers suspended in gel-like matrix [ground substance]. Skeletal System Composed of 3 Types of Connective Tissue

3. 5 Functions of Bones 1.Support 2.Movement 3.Protection 4.Formation of blood cells 5.Mineral storage

4. 1. Bone: hard inorganic matrix of calcium salts a.Compact Bone: Dense - extracellular deposits of calcium phosphate matrix w/ living cells Osteocytes- living mature bone cells that maintain structure of bone forms shafts & covers ends of long bones filled with yellow marrow Yellow marrow = Primarily fat for energy reserves Contains blood vessels & nerves Skeletal System cont.

5. b. Spongy Bone: porous bone found inside enlarged knobby ends of bones [knob = epiphysis] Internal latticework makes bones lighter & stronger Trabeculae = latticework of bones made of calcium minerals + living cells red marrow - found in spaces of trabeculae w/in long bones of upper arms & legs Stem cells w/in red marrow produce RBC’s Skeletal System cont.

6. Osteons [Haversian Systems] Cylindrical Structures (see text Fig 5.1) Osteons - as compact bone develops & hardens (ossifies) the osteocytes are trapped in hollow chambers within cylindrical osteons in such a way as to maintain contact with other osteocytes yet provide them a strong matrix to support them. Blood vessels traveling through the central Haversian canal feed the osteocytes via cell-to-cell diffusion. Waste products Diffuse away from cells, back to blood vessels.

7. Periosteum Tough Connective Tissue covering bones Contains bone forming Osteoblast cells

8. Structure of Bone Human Biology Figure 5.1 * * * * Make note of these

9. Cartilage - fibers of cartilage & elastin in gel-like matrix Function: support Types: Fibrocartilage - between vertebral disks, in knee joint Hyaline - embryonic “model” for bones, covers ends of mature bones found in joints. Elastic cartilage - outer ear, part of epiglottis Ligaments- attach bone to bone Cartilage and Ligaments

10. Prenatal: cartilage model Fetus: some conversion to bone Childhood: primary & secondary ossification sites formed Adolescence: cartilage growth plate elongates Bone Development [see Fig. 5.2 from text]

11. Bone Development ( cont.) Figure 5.2

12. Changes in: (1) shape, (2) size, (3) strength Dependent on diet, exercise, age Bone cells regulated by hormones Parathyroid hormone (PTH): removes calcium from bone Calcitonin: adds calcium to bone Repair: hematoma and callus formation Mature Bone Remodeling and Repair

13. Skeletal System: Frontal View Figure 5.5 Blue = Axial Skeleton [skull, vertebral column, ribs, Sternum] Black = Appendicular Skleton [pectoral girdle, pelvic girdle, limbs]

14. Axial Skeleton: The Skull [ Just make note of the number of bones in the skull ] Figure 5.6

15. Axial Skeleton: Vertebral Column Figure 5.7 5 areas of Axial skeleton: cervical, thoracic, lumbar, scarum, coccyx

16. Vertebral column Regions: cervical, thoracic, lumbar, sacral, coccygeal Intervertebral disks: cushion vertebrae; assist in movement, flexibility Ribs Twelve pairs Bottom two pair floating Sternum: Breastbone Three bones fused Axial Skeleton: Vertebral Column ( cont.)

17. Pectoral girdle: shoulder Clavicle, scapulas Pelvic girdles: hip Coxal bones, sacrum, pubis, ilium, ischium Limbs Arms: humerus, radius, ulna, wrist and hand bones Legs: femur, tibia, fibula, ankle and foot bones Appendicular Skeleton

18. Classified by degree of movement Fibrous joint: immovable (e.g., fontanels) Cartilagenous joint: slightly movable, cartilage connection (e.g., backbone) Synovial joint: freely movable (e.g., knee) Joints (Articulations)

19. Synovial Joints Figure 5.12A

20. Joint capsule: synovial membrane + hyaline cartilage Synovial membrane secretes synovial fluid as lubricant Hyaline cartilage cushions Synovial Joints ( cont.)

21. Sprains: stretched or torn ligaments Bursitis and tendinitis: inflammation of bursae or tendons Arthritis: inflammation of joints Diseases and Disorders of the Skeletal System