Chapter 7

1. Chapter 7 Skeletal System *You may want to attach paper to your study guide for further room for writing

2. Aids to Understanding Words • Complete the Aids to Understanding Words • You may just write what is in the parentheses • You may also want to write “key words” or “clues”

3. Living Tissues of Bone • Bone tissue • Cartilage • Dense connective tissue • Blood • Nervous tissue

4. Classifying Bones by Their Shape • Long bones – long longitudinal axes, expanded at each end • Thigh bones, forearms • Short bones – cubelike, lengths/widths equal • Wrists, ankles • Flat bones - platelike, broad surfaces • Ribs, scapula, bones of skull

5. Classifying Bones • Irregular bones – variety of shapes, usually connected to other bones • Vertebrae, facial bones • Sesamoid (round) bones – small and nodular, embedded within tendons (muscle to bone), adjacent to joints • Kneecap (patella)

6. Parts of a Long Bone • Use the worksheet provided to label these parts AND write their functions (p.132 Fig.7.1) • Epiphysis (proximal and distal) • Diaphysis • Periosteum • Compact bone • Spongy bone • Medullary Cavity • Red Marrow (spaces) *see sheet • Yellow Marrow *see sheet

7. Bone Structure and Function • Bones have projections called “processes” that provide attachment sites for ligaments and tendons • Some bones have small holes to allow passage of blood vessels and nerve fibers • Shape of bones helps them to fit together

8. Periosteum • Vascular, fibrous tissue covering the bone • Function – formation and repair of bone tissue • Generally located on the diaphysis (shaft)

9. Compact Bone vs. Spongy Bone • Compact • continuous matrix with no gaps • typically form outer walls of long bones • Spongy • branching bony plates • irregular connecting spaces • lace-like appearance • found in hollow tube of compact bone (long bone)

10. Osteocytes • Osteocytes – bone cells • Found in lacunae (bony chambers) • Form concentric circles around the central canal • Look at page 108 to refresh your memory *cellular matrix of bone is composed of collagen (resilience) and calcium phosphate (hardness)

11. Flashcard Time! • Use the notecards provided to make flashcards for the following: • Long bones * • Short bones * • Flat bones * • Irregular bones * • Sesamoid bones * *also list examples with the description

12. Flashcards Continued! • Epiphysis • Diaphysis • Compact bone • Spongy bone • Medullary cavity Worth 10 points - due by the end of class!

13. Bone Development/Growth:Intramembranous Bone • Broad, flat bones of skull - form during first weeks of embryonic development • Membrane-like layers appear at future bone sites • Tissues enlarge to form osteoblasts • Osteoblasts deposit bony matrix  spongy bone  periosteum  compact bone (between periostem and spongy) • Ossification – formation of bone

14. Bone Development/Growth:Endochondral Bones • Most of the bones of the body – develop in fetus from masses of hyaline cartilage • Models of cartilage grow rapidly and then begin to change • Long bones - cartilage breaks down and disappears • Periosteum forms  encircles diaphysis  blood vessels and osteoblasts form spongy bone

15. Ossification of Endochondral Bones • Primary Ossification Center (diaphysis) • first region of bone formation, development proceeds to ends of bone • Secondary Ossification Center (epiphysis) • Spongy bone forms in all directions • Epiphyseal plate (cartilage) remains between centers

16. Epiphyseal Plate • Epiphyseal plate contains dividing cells that lengthen the bone • When the centers meet and the plate ossifies – lengthening is no longer possible • Look at page 134, Fig. 7.5 • What happens if the plate is damaged before it ossifies?

17. Ossification • Complete when adult size is reached • Homeostasis of bone tissue • Life long process of bone remodeling • Osteoclasts (cells that erode bone) reabsorb bone matrix • Osteoblasts (bone-forming cells) replace bone matrix • Hormones that control blood calcium help control the resorption and deposition (3-5% exchanged of bone calcium exchanged each year)

18. How is a fracture healed?Pages 136 - 137 • Blood vessels rupture, and periosteum tears • Blood spreads and develops a hematoma (blood clot) • Vessels in surrounding tissues dilate – causing swelling and inflammation • Osteoblasts and new blood vessles invade the hematoma and form spongy bone

19. Fracture Healing ( continued) • Fibroblasts farther from a blood supply produce masses of fibrocartilage • Phagocytes and osteoclasts remove the hematoma and other bone debris • Fibrocartilage fills the gap between the ends of the broken bone • The cartilaginous callus is replaced by bone tissue • Phew! Smaller the fracture, faster the healing.

20. Factors Affecting Bone Growth/Development • Nutrition • Vitamin D for proper absorption of Calcium • Hormonal secretions • Growth hormones stimulate cell division • Sex hormones stimulate ossification of ephiphyseal plates (Why sex hormones?) • Physical exercise • Provides stress needed to thicken and strengthen bones

21. Book Work! • Page 171, Chapter Assessments #s 1-8 • Save this paper! You will be adding to it!!!