Bones of the Skeleton - Anatomy Lecture Notes PDF

Bones of the Skeleton Two main groups, by location Axial skeleton (brown) Appendicular skeleton (yellow) Copyright © 2010 Pearson Education, Inc.  Cartilage in Cartilages in external ear no...

Bones of the Skeleton Two main groups, by location Axial skeleton (brown) Appendicular skeleton (yellow) Copyright © 2010 Pearson Education, Inc.  Cartilage in Cartilages in external ear nose Articular Cartilage of a joint Cartilage in Costal Intervertebral cartilage disc Pubic symphysis Meniscus (padlike cartilage in knee joint) Articular cartilage of a joint Copyright © 2010 Pearson Education, Inc. Figure 6.1 Copyright © 2010 Pearson Education, Inc. Figure 6.2  Functions of Bones Support For the body and soft organs Protection For brain, spinal cord, and vital organs Movement Levers for muscle action Copyright © 2010 Pearson Education, Inc.  Functions of Bones Storage Minerals (calcium and phosphorus) and growth factors Blood cell formation (hematopoiesis) in marrow cavities Triglyceride (energy) storage in bone cavities Copyright © 2010 Pearson Education, Inc.  Bone Markings Bulges, depressions, and holes serve as Sites of attachment for muscles, ligaments, and tendons Joint surfaces Conduits for blood vessels and nerves Copyright © 2010 Pearson Education, Inc.  Bone Markings: Projections Sites of muscle and ligament attachment Tuberosity—rounded projection Crest—narrow, prominent ridge Trochanter—large, blunt, irregular surface Line—narrow ridge of bone Tubercle—small rounded projection Epicondyle—raised area above a condyle Spine—sharp, slender projection Process—any bony prominence Copyright © 2010 Pearson Education, Inc. Copyright © 2010 Pearson Education, Inc. Table 6.1  Bone Markings: Projections Projections that help to form joints Head Bony expansion carried on a narrow neck Facet Smooth, nearly flat articular surface Condyle Rounded articular projection Ramus Armlike bar Copyright © 2010 Pearson Education, Inc. Copyright © 2010 Pearson Education, Inc. Table 6.1  Bone Markings: Depressions and Openings Meatus Groove Canal-like passageway Furrow Sinus Fissure Cavity within a bone Narrow, slitlike opening Fossa Foramen Shallow, basinlike Round or oval opening depression through a bone Copyright © 2010 Pearson Education, Inc. Copyright © 2010 Pearson Education, Inc. Table 6.1  Bone Textures Compact bone Dense outer layer Spongy (cancellous) bone Honeycomb of trabeculae Copyright © 2010 Pearson Education, Inc.  Structure of a Long Bone Diaphysis (shaft) Compact bone collar surrounds medullary (marrow) cavity Medullary cavity in adults contains fat (yellow marrow) Copyright © 2010 Pearson Education, Inc.  Structure of a Long Bone Epiphyses Expanded ends Spongy bone interior Epiphyseal line (remnant of growth plate) Articular (hyaline) cartilage on joint surfaces Copyright © 2010 Pearson Education, Inc.  Articular cartilage Compact bone Proximal epiphysis Spongy bone Epiphyseal line Periosteum Compact bone Medullary cavity (lined (b) by endosteum) Diaphysis Distal epiphysis (a) Copyright © 2010 Pearson Education, Inc. Figure 6.3a-b  Membranes of Bone Periosteum Outer fibrous layer Inner osteogenic layer Osteoblasts (bone-forming cells) Osteoclasts (bone-destroying cells) Osteogenic cells (stem cells) Nerve fibers, nutrient blood vessels, and lymphatic vessels enter the bone via nutrient foramina Endosteum Also contains osteoblasts and osteoclasts Copyright © 2010 Pearson Education, Inc.  Endosteum Yellow bone marrow Compact bone Periosteum Perforating (Sharpey’s) fibers Nutrient arteries (c) Copyright © 2010 Pearson Education, Inc. Figure 6.3c  Structure of Short, Irregular, and Flat Bones Periosteum-covered compact bone on the outside Endosteum-covered spongy bone within Spongy bone called diploë in flat bones Bone marrow between the trabeculae Copyright © 2010 Pearson Education, Inc.  Spongy bone (diploë) Compact bone Trabeculae Copyright © 2010 Pearson Education, Inc. Figure 6.5  Location of Hematopoietic Tissue (Red Marrow) Red marrow cavities of adults Trabecular cavities of the heads of the femur and humerus Trabecular cavities of the diploë of flat bones Red marrow of newborn infants Medullary cavities and all spaces in spongy bone Copyright © 2010 Pearson Education, Inc.  Microscopic Anatomy of Bone Cells of bones Copyright © 2010 Pearson Education, Inc.  Cells of bones (a) Osteogenic cell (b) Osteoblast Stem cell Matrix-synthesizing cell responsible for bone growth Copyright © 2010 Pearson Education, Inc. Figure 6.4a-b  (c) Osteocyte (d) Osteoclast Mature bone cell Bone-resorbing cell that maintains the bone matrix Copyright © 2010 Pearson Education, Inc. Figure 6.4c-d  Microscopic Anatomy of Bone: Compact Bone Haversian system, or osteon—structural unit Lamellae Weight-bearing Column-like matrix tubes Central (Haversian) canal Contains blood vessels and nerves Copyright © 2010 Pearson Education, Inc.  Microscopic Anatomy of Compact Bone Artery with capillaries Structures in the Vein central Nerve fiber canal Lamellae Collagen fibers run in different directions Twisting force Copyright © 2010 Pearson Education, Inc. Figure 6.6  Compact Spongy bone bone Central Perforating (Haversian) canal (Volkmann’s) canal Endosteum lining bony canals Osteon and covering trabeculae (Haversian system) Circumferential lamellae (a) Perforating (Sharpey’s) fibers Lamellae Periosteal blood vessel Periosteum Nerve Vein Artery Lamellae Central Lacuna (with Canaliculi canal osteocyte) Osteocyte Lacunae in a lacuna (b) (c) Interstitial lamellae Copyright © 2010 Pearson Education, Inc. Figure 6.7a-c  Nerve Vein Lamellae Artery Central Canaliculus canal Osteocyte Lacunae in a lacuna (b) Copyright © 2010 Pearson Education, Inc. Figure 6.3b  Microscopic Anatomy of Bone: Spongy Bone Trabeculae Align along lines of stress No osteons Contain irregularly arranged lamellae, osteocytes, and canaliculi Capillaries in endosteum supply nutrients Copyright © 2010 Pearson Education, Inc.  Chemical Composition of Bone: Organic Osteogenic cells, osteoblasts, osteocytes, osteoclasts Osteoid—organic bone matrix secreted by osteoblasts Ground substance (proteoglycans, glycoproteins) Collagen fibers Copyright © 2010 Pearson Education, Inc.  Chemical Composition of Bone: Inorganic Hydroxyapatites (mineral salts) 65% of bone by mass Mainly calcium phosphate crystals Responsible for hardness and resistance to compression Copyright © 2010 Pearson Education, Inc.  Differentiate between…. Endochondral ossification Intramembranous ossification Mechanisms Where and when does each occur// Copyright © 2010 Pearson Education, Inc.