1. Skeletal Tissue & System
Bone “osteo”

2. Cancellous (Spongy) Bone Bone Cells Bone Marrow Calcium Regulation
Types of bones
Parts of long bones
Bone Tissue
Bone Matrix
Inorganic Salts
Osteoporosis
Organic Matrix
Compact Bone
Cancellous (Spongy) Bone
Bone Cells
Bone Marrow
Calcium Regulation
Bone Development
The Skeleton
The Skull
The Vertebral Column

3. Functions of Bone Support
Contribute to shape, alignment and position of body
Protection (axial)
Skull-brain, ribs-heart, lungs
Movement (appendicular)
Muscles are anchored to bones which act as levers
Mineral Storage
Reservoir for calcium, phosphorus and other minerals
Calcium moves into or out of bones to keep blood levels steady
Hematopoiesis
Blood cell formation, occurs primarily in red marrow

4. Bone Cells Osteoblasts Osteoclasts Osteocytes Osteoclasts Osteocyte
Bone building cells
Secrete ground substance
Allows for deposition of Ca and phosphate
Osteoclasts
Bone destroyer cells
Giant multinucleated cells
Contain large number of lysosomes
Osteocytes
Mature bone cells
Are walled into lacunae in matrix
Osteoclasts
Osteocyte

5. Bone Marrow Also called myeloid tissue
Found in medullary cavities of long bones and spaces of spongy bone
Red Marrow
Makes up almost all marrow in infants
Produces red blood cells
Gradually changes to yellow marrow
Found in ribs, pelvis, sternum, humerus & femur
Yellow marrow
Made up of adipose tissue
During time of low blood level it can convert back to red marrow

6. Types of bones Long Bones Short Bones Flat Bones Irregular Bones
Long axis with unique shaped articular ends
ex: femur (thigh), humerus (arm)
Short Bones
Cube or box shaped
ex: wrist (carpals) or ankle (tarsals) bones
Flat Bones
Broad and thin with often curved surfaces
Red marrow is found in some flat bone like the sternum
ex: shoulder blades (scapula), breastbone (sternum) and ribs
Irregular Bones
Come in clusters and come in various shapes and sizes
Sesamoid bones are irregular bones that are found alone
ex: vertebral bones, facial bones, patella

7. Long Bones
Flat Bones
Irregular Bones
Short Bones

8. Parts of a long bone Diaphysis Main shaft portion of bone
Cylindrical and hollow
Very strong yet light
Epiphyses
Bulbous shape at end of bones
Site of muscle attachments
Made of spongy, cancellous tissue filled with red marrow
Epiphyseal plate (Growth plate)
layer of cartilage seen in early development
separates epiphyses from Diaphysis.
Articular Cartilage
Thin layer of hyaline cartilage that covers epiphysis
Cushions jolts and blows

9. Parts of a long bone Periosteum Medullary (marrow) cavity Endosteum
Dense white fibrous tissue, covers bone and joint surfaces
Muscle & tendon fibers interlace with periosteal fibers anchoring them into place
Contains bone forming and destroying cells
Contains blood vessels that aid in born formation and repair of bone
Medullary (marrow) cavity
Hollow space of diaphysis
Filled with fatty yellow marrow
Endosteum
Thin membrane that lines medullary cavity

10. Bone (osseous) Tissue Made of cells, fibers and extracellular fluid
Extracellular material is hard and calcified
Contains many collagen fibers
Tensile strength equal to iron with 1/3 the weight.
Structure allows bone to carry out its supportive and protective function
Collagen Fibers
Cross section of rib

11. Compact Bone Haverisan systems or Osteons
functional units of compact bone
Main function is to provide nutrients and remove wastes from osteocytes that are “trapped” in the bone
4 Main components
Lamelle- concentric cylindrical layers of calcified matrix
Lacunae- “little lake” small spaces where cells are imprisoned
Canaliculi- small canals radiated from lacunae that connect cells to larger canal
Haversian canals- lengthwise canals that contain blood and lymph vessels, and nerves.

12. Cancellous (Spongy) Bone
Made of needle like spicules call trabeculae
Lack Haversian systems but do contain canaliculi for nutrient & waste removal
Trabeculae are oriented along stress lines to enhance bones strength
Stores red marrow
Found in between flat bones and epiphysis of long bones

13. Osteoporosis
Age related disease which results on loss of bone mineral density
Causes bone fragility and susceptibility to fractures
White women during the first 10 years of menopause are most susceptible
Treatment
hormone replacement therapy (HRT)
Non-hormonal drugs, Fosamax
Calcium supplements
Weight bearing exercise
healthy
osteoporosis

14. Extra Bones?!
Wormian (Sutural) Bones-found in sutures (joints) between cranial bones
Sesamoid Bones-found in tendons, esp. in hands and feet

15. Divisions of Skeletal System? ?
Divisions of Skeletal System ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

16. Major Bones of the Skull

17. Hyoid Bone Single U shaped bone just above the larynx
Tongue muscles attached
Only bone to articulate on its own.
Part of the axial skeleton

18. The Spine

19. Regulation of Blood Calcium levels
Functions of Ca
Bone formation
Nerve impulse transmission
Skeletal and Cardiac muscle contraction
Parathyroid hormones
When blood Ca is LOW the parathyroid will release PTH
PTH is the most critical factor in Ca homeostasis
This stimulates osteoclasts to breakdown bone
Increases renal absorption of Ca
Increases synthesis if Vitamin D with increase Ca absorption
When blood Ca is HIGH osteoclast activity is suppressed
The thyroid will release Calcitonin
Calcitonin stimulates osteoblast activity, depositing Ca

20. Bone Development- Ossification
Osteogenisis- process in which cartilage is converted into hard bone by the work of osteoblasts and osteoclasts
*Fontanels- soft spot in infants, remain until bones in skull fuse.

21. Bone Development- Ossification
Intramembranous Ossification
when connective tissue in replaced by bone
Spongy bone is created first and then covered by compact bone
Results in Appositional growth, bone growth on the outer surface(wider/bigger)

22. Bone Development- Ossification
Endochondrial Ossification
Progresses from diaphysis to epiphysis
Increases bone length
Epiphyseal plate remains as cartilage until one growth is complete
Young children and pre teens are susceptible to epiphyseal fractures

23. Rickets Vitamin D is essential to bone calcification
If children are deficient in Vitamin D their epiphyseal plate with length but fail to calcify
The bone bends and deforms under weight-bearing

24. Fractures and Breaks

25. Fractures and Breaks

28. Male vs. Female Skeleton