1. SKELETAL TISSUE AND PHYSIOLOGY

2. CARTILAGE Connective tissue Fibers embedded in firm gel Avascular
Chondrocytes lie in lacunae
Nutrients delivered by diffusion

3. 3 TYPES Fibrocartilage – menesci of knee and between vertebrae
Elastic – external ear and epiglottis
Hyaline – articular, chondral, laryngeal, tracheal and bronchial

4. FUNCTIONS OF SKELETON Support Protection
Movement –bones and joints – levers
Mineral reservoir – Ca++, Phosphorus
Hemopoiesis – blood cell formation

5. TYPES OF BONES Long – humerus, femur, ulna, radius, tibia, fibula
Short – carpals and tarsals
Flat – skull, ribs, patella, scapula
Irregular – vertebrae, facial bones, hyoid

6. MACROSCOPIC STRUCTURE OF LONG BONES
Diaphysis – main shaft like portion; hollow, cylindrical, thick compact bone
Epiphysis(-es) – end of long bones – bulbous shape provides generous space for muscle attachments – spongy (cancellous) bone filled with yellow marrow except in proximal epiphyses of humerus and femur (red)

7. Articular cartilage – thin layer of hyaline cartilage that covers joint surfaces of epiphyses – shock absorber
Periosteum –dense, white fibrous membrane that covers bone everywhere but joint surfaces – Sharpey’s fibers penetrate bone – muscle fibers interlace with these providing a firm anchor – BVs from periosteum nourish bone –

8. - OSTEOBLASTS (bone building cells) compose inner periosteum
5. Medullary cavity – marrow containing cavity in diaphysis
6. Endosteum – membrane lining medullary cavity

10. SHORT, FLAT AND IRREGULAR BONES
Cancellous bone covered w/compact bone
Red marrow fills spaces in cancellous bone inside a few irregular and flat bones (vertebrae and sternum)
Needle aspiration – diagnostic tool

11. BONE TISSUE
Connective tissue – cells, fibers (collagen) and calcified matrix
More matrix than cells; lots of collagen
Strength of cast iron, 1/3 the mass

12. BONE MATRIX
Inorganic salts – APATITE (crystals of calcium and phosphate) gives bone its hardness – oriented to resist stress
Organic matrix – collagen and ground substance – amorphous mixture of protein and polysaccharides

13. MICROSCOPIC STRUCTURE OF BONE
Compact bone composed of Haversian system
Lamellae – concentric cylinders of calcified matrix
Lacunae – small spaces containing tissue fluid in which osteocytes lie between lamellae
Canaliculi – small canals radiating from lacunae, connecting them to each other and the Haversian canal

14. Haversian canal – extends through center of each Haversian system – blood and lymph transport O2 and nutrients to bone cells
- BVs from periosteum penetrate bone via Volkmann’s canals; arteries supply marrow
Cancellous bone – NO Haversian systems; weblike arrangement of marrow filled spaces separated by trabeculae (thin processes of bone)

20. BONE MARKINGS DEPRESSIONS AND OPENINGS Fossa Sinus Foramen Meatus
Sulcus

21. B. PROJECTIONS AND PROCESSES
1. Condyle
2. Head
3. Trochanter
4. Crest
5. Spinous process
6. Tuberosity
7. Tubercle

22. DEVELOPMENT OF BONE - OSTEOGENESIS
1. Intramembranous ossification
happens in connective tissue membrane
Includes broad flat bones of the skull
Membrane like layers of primitive connective tissue appear at the site of future bone
Layers supplied with blood – connective tissue cells arrange themselves around the blood vessel

23. These cells differentiate into osteoblasts
Osteoblasts deposit bony matrix – produce spongy bone
Osteoblasts become surrounded by bony matrix – in lacunae, osteocytes
Osteoblasts on inside of periosteum give rise to compact bone

27. 2. Endochondral
Formed from hyaline cartilage model
Periosteum develops, enlarges, and forms subperiosteal collar
1o ossification center develops as cartilage begins to calcify and BVs enter rapidly changing cartilage model at midpoint of diaphysis
Ossification proceeds from diaphysis to epiphysis
Bone grows in length

28. 2o ossification center appears at epiphyses and growth proceeds from epiphysis to diaphysis
Until bone length growth is complete, a layer of cartilage (epiphyseal cartilage) remains between diaphysis and epiphysis
Epiphyseal cartilage thickens during growth periods
This cartilage ossifies – osteoblasts make organic bone matrix, matrix calcifies – bone grows longer

30. Tibial epiphysis

32. BONE GROWTH AND RESORPTION
Bone growth – diameter
Osteoclasts
Osteoblasts
Ossification and resorption occur concurrently
In adult years, rate =
Childhood and adolescence, ossification > resorption
years, resorption > ossification

34. BONE FRACTURES AND REPAIRS
Fracture – break in bone’s continuity
Simple – skin unbroken
Compound – skin broken
Alignment = reduction
Closed reduction = fracture set without opening skin
Open reduction – requires surgical incision
Osteomyelitis
Kids – greenstick fractures – bone cracked

36. HEALING OF FRACTURES
Dead bone – removed by osteoclasts or serves as framework for CALLUS (repair tissue)
Callus – periosteal and endosteal cells differentiate into chondroblasts and osteoblasts
Callus binds broken ends – callus tissue is eventually replaced by normal bone