Title: Skeletal%20Tissue%20
1Skeletal Tissue System
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3- 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
4Functions of Bone
- Support
- Contribute to shape, alignment and position of
body - Protection
- Skull-brain, ribs-heart, lungs
- Movement
- 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
5Types of bones
- Long 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), breatbone(sternum)
and ribs - Irregular Bones
- Come in clusters and come in various shapes and
sizes - Sesamoid bones are irregular bones that are found
alone, kneecap(patella) - ex vertebral bones, facial bones
6Long Bones
Flat Bones
Irregular Bones
Short Bones
7Parts 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
- layer of cartilage seen in early development
- separates epiphyses from Diaphysis.
- In mature bone is referred to as the metaphysis
- Articular Cartilage
- Thin layer of hyaline cartilage that covers
epiphysis - Cushions jolts and blows
8Parts of a long bone
- Periosteum
- Dense white fibrous tissue, covers bone and joint
surfaces - Periosteum fibers penetrate underlying bone
- 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
9Bone (osseous) Tissue
- Made of cells, fibers and extracellular fluid
- Extracellular material predominates and 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
10Bone Matrix
- Inorganic Salts
- Hydroxyapatite- specialized crystals of Calcium
and phosphate - Hardness of bone results from the deposition of
hydroxyapatite - Other minerals found in bone are magnesium,
sodium, sulfate, and fluoride.
11Osteoporosis
- 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
12Bone Matrix
- Organic Matrix
- Composite of collagenous fibers and ground
substance - Ground substance
- Gel like substance
- Made of protein and polysaccharides
- Provides support and adhesion
- Aids in growth, repair, and remodeling
- Adds to overall strength and resistance of bone
As the marrow tissue invades the cell columns,
spicules of cartilage will be left. The cartilage
matrix is calcified (purple), and one small area
of bone deposition, has begun on it (the red
color at the upper right). The small cells caught
in the red matrix are osteocytes.
13Compact 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
14Compact Bone
- 4 Main components
- Lamelle- concentric cylindrical layers of
calcified matrix - Lacunae- little lakesmall 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. - Volkmanns Canals- horizontal canals that connect
Haversian canals
15Cancellous (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 ephiysis of long
bones
16Divisions of Skeletal System
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17Major Bones of the Skull
18Hyoid Bone
- Single U shaped bone just above the larynx
- Tongue muscles attached
- Only bone to articulate on its own.
- Part of the axial skeleton
19The Spine
20Bone Cells
- Osteoblasts
- 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
21Bone 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
22Regulation 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
23Bone 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.
24Bone 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)
25Bone 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
26Rickets
- 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
27Fractures and Breaks
28Fractures and Breaks
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31Male vs. Female Skeleton