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Ch. 6 and 7 Skeletal System. Anatomy and Physiology . 6.1 Functions of the Skeletal System. Support Not just place to hang muscles – need bones for framework Muscles need something to pull against Site for organs and soft tissues Storage of minerals and lipids - PowerPoint PPT Presentation
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Ch. 6 and 7Skeletal System
Anatomy and Physiology
1. Support1. Not just place to hang muscles – need bones for framework2. Muscles need something to pull against3. Site for organs and soft tissues
2. Storage of minerals and lipids1. Osmotic concentration/ reaction rate/ coenzymes2. Calcium, potassium, sodium, magnesium, carbonate, phosphate3. Lipids in yellow marrow
3. Blood cell production1. Red bone marrow – inner cavity of bones2. Makes red blood cells, white blood cells and other components of blood
4. Protection1. Ribs protect heart and lungs2. Skull enclosed brain, etc
5. Leverage1. Movement of skeletal muscles depends on leverage against skeleton
6.1 Functions of the Skeletal System
1. Sutural 1. Found in skull; they look like they have been ‘sutured ‘ or
sewn together2. Irregular
1. Complex shapes; vertebrae, pelvis and skull3. Short bones
1. Small and boxy; wrist and ankle4. Flat bones
1. Flat and thin; skull, sternum, ribs, scapulae/ protection and lots of surface area to anchor muscle
5. Long bones1. Long and slender; arms, legs, fingers, toes
6. Sesamoid bones1. Vary in number, found in tendons, disc or seed shaped; knee
cap
6.2 Bone Shapes: shape or internal organization
© 2012 Pearson Education, Inc.
Figure 6-1 A Classification of Bones by Shape
Sutures
Suturalbone
Vertebra
Carpalbones
Parietal bone External table
Internaltable
Diploë(spongy
bone)
Humerus
Patella
Sutural Bones Flat Bones
Long Bones
Sesamoid Bones
Irregular Bones
Short Bones
Surface structures known as landmarks Elevations or projections
◦ These are sites for tendons and ligaments to attach and bones to articulate (joints = articulations)
Depressions, grooves and tunnels◦ Places where blood vessels or nerves ran along
side a bone Used to determine age, gender, size and
appearance of individual (skeletal remains)
Bone markings
Diaphysis – length of long bone◦ Wall is compact or dense bone; sturdy◦ Center is medullary cavity; marrow
Epiphysis – ‘end’◦ Spongy bone aka cancellous or trabecular bone ◦ Open network like lattice ◦ With thin cortex or covering
Metaphysis – ‘between’ where diaphysis meets the epiphysis
Bone structure – page 172 *
© 2012 Pearson Education, Inc.
Figure 6-2 Bone Structure
Epiphysis
Diaphysis(shaft)
Metaphysis
Medullarycavity
Compactbone
Spongybone
Epiphysis
Metaphysis
Cortex(compact bone)
Diploë(spongy bone)
The structure of a flat bone(the parietal bone)
The structure of a representativelong bone (the femur) inlongitudinal section
© 2012 Pearson Education, Inc.
Table 6-1 An Introduction to Bone Markings
SinusTrochanter
Head
Neck
Facet
Tubercle
CondyleFemur
Fissure
Ramus
Foramen
Process
Skull
Tubercle HeadSulcusNeck
Tuberosity
Fossa
Trochlea
CondyleHumerus
Crest
Fossa
Spine
Line
ForamenRamus
Pelvis
6.3 Bone or osseous tissue = supporting connective tissue; matrix, fibers and cells Matrix
◦ Dense with calcium salts Ca3(PO4)2◦ and collagen fibers (like rebar in concrete)◦ Cells are in pockets called lacunae◦ Organized around blood vessels◦ Canaliculi are passages through matrix branching
between lacunae and blood vessels◦ Periosteum – fiberous (outer) and cellular (inner)
layer that covers bone surfaces Cells
◦ Osteocytes, osteoblasts, osteoprogenitor cells and osteoclasts
Osteocytes◦ Bone cells◦ Most common◦ 1 per lacuna, surrounded by layers of lamellae◦ Can not divide◦ Neighboring osteocytes are linked by gap junctions through the canaliculi◦ Maintain mineral content and help to repair fractures◦ Can become other cell types
Osteoblasts◦ Produce new matrix
Osteoprogenitor cells◦ Produce osteoblasts that could repair a fracture
Osteoclasts ◦ Remove and recycle matrix as needed; “resorption”◦ 50 + nuclei◦ Very large◦ Come from marrow (stem cells) and not osteoprogenitor cells◦ Can make bones larger/stronger to match muscle mass or smaller
through disuse
Bone Cells
Compact bone / Spongy bone Compact bone
◦ Osteocytes are in concentric layers around a Haversian canal = osteon
◦ Lamella are in concentric layers (target like pattern)
◦ Thickest were there is stress to bear weight Femur bears 15 X body
weight before breaking – when force is end to end; breaks when force is from side
Spongy bone◦ Lamella not in osteons◦ Bundles of fibers =
trabeculae◦ Red marrow
Blood cell formation◦ Yellow marrow
Adipose/ energy reserve◦ Locations without stress;
not as dense (<weight)
© 2012 Pearson Education, Inc.
Figure 6-6 The Structure of Spongy Bone
Trabeculae ofspongy bone
Canaliculi openingon surface
Endosteum Lamellae
Figure 6-5 The Structure of Compact Bone
VenuleCapillaryPeriosteum
Circumferentiallamellae
Osteons
Perforatingfibers Interstitial
lamellae
Concentriclamellae
Trabeculae ofspongy bone(see Fig.6–6)
Vein
Artery ArterioleCentralcanal
Perforatingcanal
The organization of osteons andlamellae in compact bone
The orientation of collagenfibers in adjacent lamellae
Collagenfiberorientation
Endosteum
Centralcanal
Concentriclamellae
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