Anatomy and Physiology

1. Support 1.Not just place to hang muscles – need bones for framework 2.Muscles need something to pull against 3.Site for organs and soft tissues 2. Storage of minerals and lipids 1.Osmotic concentration/ reaction rate/ coenzymes 2.Calcium, potassium, sodium, magnesium, carbonate, phosphate 3.Lipids in yellow marrow 3. Blood cell production 1.Red bone marrow – inner cavity of bones 2.Makes red blood cells, white blood cells and other components of blood 4. Protection 1.Ribs protect heart and lungs 2.Skull enclosed brain, etc 5. Leverage 1.Movement of skeletal muscles depends on leverage against skeleton

1. Sutural 1.Found in skull; they look like they have been ‘sutured ‘ or sewn together 2. Irregular 1.Complex shapes; vertebrae, pelvis and skull 3. Short bones 1.Small and boxy; wrist and ankle 4. Flat bones 1.Flat and thin; skull, sternum, ribs, scapulae/ protection and lots of surface area to anchor muscle 5. Long bones 1.Long and slender; arms, legs, fingers, toes 6. Sesamoid bones 1.Vary in number, found in tendons, disc or seed shaped; knee cap

© 2012 Pearson Education, Inc. Figure 6-1 A Classification of Bones by Shape Sutures Sutural bone Vertebra Carpal bones Parietal bone External table Internal table 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)

 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

© 2012 Pearson Education, Inc. Figure 6-2 Bone Structure Epiphysis Diaphysis (shaft) Metaphysis Medullary cavity Compact bone Spongy bone Epiphysis Metaphysis Cortex (compact bone) Diploë (spongy bone) The structure of a flat bone (the parietal bone) The structure of a representative long bone (the femur) in longitudinal section

© 2012 Pearson Education, Inc. Table 6-1 An Introduction to Bone Markings Sinus Trochanter Head Neck Facet Tubercle Condyle Femur Fissure Ramus Foramen Process Skull Tubercle Head Sulcus Neck Tuberosity Fossa Trochlea Condyle Humerus Crest Fossa Spine Line Foramen Ramus Pelvis

 Matrix ◦ Dense with calcium salts Ca 3 (PO 4 ) 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

 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 of spongy bone Canaliculi opening on surface Endosteum Lamellae

Figure 6-5 The Structure of Compact Bone Venule Capillary Periosteum Circumferential lamellae Osteons Perforating fibers Interstitial lamellae Concentric lamellae Trabeculae of spongy bone (see Fig.6–6) Vein ArteryArteriole Central canal Perforating canal The organization of osteons and lamellae in compact bone The orientation of collagen fibers in adjacent lamellae Collagen fiber orientation Endosteum Central canal Concentric lamellae