1. Skeletal System
Textbook: Chapter 7

2. Functions Support – frame on which everything else builds
Protection – skull and thorax
Movement – connections with muscles
Storage – storage of Ca and other ions
Hematopoiesis – in red marrow

3. Types of Bones Long Bones - humerus Short Bones - carpals
Flat Bones - frontal
Irregular Bones - vertebrae

4. Long Bones Main Parts Diaphysis (shaft) Medullary Cavity Epiphyses
Articular Cartilage
Periosteum
Endosteum
Epiphyseal plate/disk

5. A. Structure of Bone
The skeletal system is composed of two major types of tissue – bone and cartilage
Bone cells = osteocytes
Cartilage cells = chondrocytes

7. B. Types of bone Compact Bone Covered by periosteum Appears solid
Composed of osteons
Lamella - rings
Lacunae – b/w lamella, contain osteocytes
Calaliculi – canals that reach osteocytes
Central canal – blood vessel

8. B. Types of bone 2. Spongy Bone Appears porous Found in epiphyses
Spaces contain red bone marrow
Needle threads that create
“sponge” = trabeculae

9. C. Cartilage Chondrocytes found in lacunae
Matrix is flexible and contains collagen
No blood vessels
Slow to heal

10. Bone Formation and Growth
New bone cells = osteoblasts; Resorbing cells = osteoclasts
Ability of bone to grow and change is dependent on the osteoblasts and osteoclasts
Bone Growth = ossification
Endochondral Ossification –formed from cartilage
Intramembranous Ossification
Hematopoietic Ossification

11. Endochondral Ossification
Bone formation begins from cartilage
Blood vessel invades at diaphysis
Osteoblasts/clasts result – center of ossification appears in diaphysis
Centers of ossification appear in epiphyses
Ephyseal Plate appears
Bone grows

15. Endochondral Ossification
Bone continues to grow while the cartilaginous cells of the epiphyseal plate are active –once ossification center meet growth stops
Osteoblasts deposit bone material under periosteum – bone grows
Osteoclasts erode medullary cavity

16. Skeleton Organization
Axial Skeleton
Skull
8 Cranial Bones
Frontal
Parietal (2)
Occipital
Temporal (2)
Sphenoid
Ethmoid
ii. 14 Facial Bones
1. maxilla (2)
2. zygomatic (2)
3. palatine (2)
4. Inferior nasal concha (2)
5. Mandible
6. Lacrimal (2)
7. Nasal (2)
8. Vomer

19. Skeletal Organization
b. Middle ear bones 1. malleus (2) 2. incus (2) 3. stapes (2)

21. Skeletal Organization
c. Hyoid bone

22. Skeletal Organization
d. Vertebral Column 1. Cervical Vertebrae (7) -atlas supports head 2. Thoracic Vertebrae (12) -larger than cervical -facets on sides articulate with ribs 3. Lumbar Vertebrae (5) -large and strong 4. Sacrum -five fused vertebrae 5. Coccyx -four fused vertebrae -shock absorber

24. Skeletal Organization
e. Thoracic Cage 1. Ribs a. 7 True Ribs b. 5 False Ribs c. 2 Floating Ribs 2. Sternum -consists of manubrium, body, and xiphoid process -articulates with clavicles

26. Skeleton Organization
2. Appendicular Skeleton
-connected to axial skeleton by pectoral girdle and pelvic girdle
Upper extremities
Pectoral Girdle
-clavicles – hold muscles and shoulders in place
-scapula – broad triangular bones that articulate with the humerus

29. Skeletal Organization
2. Upper Limb
- Humerus – scapula to elbow, articulates with radius and ulna
- Radius – thumb side of forearm, articulates with humerus, ulna, and wrist
- Ulna – overlapes radius posteriorly, articulates with radius laterally
- Hand
- 8 carpal bones (carpus)
- 5 metacarpal bones and 14 phalanges

31. Skeletal Organization
b. Lower extremities 1. Pelvic Girdle - sacrum, coccyx, and pelvic girdle = pelvis - coxal bones -ilium – joins sacrum -ischium – lowest part, supports weight when sitting -pubis – anterior portion, fused anteriorly

33. Skeletal Organization
2. Lower Limb - Femur – hip to knee, articulates with patella - Tibia – medial side of leg, articulates with talus - Fibula – lateral side of tibia, articulates with ankle - Foot -tarsus - 5 metatarsals -14 phalanges