Skeletal System: Osseous Tissue(Chapter 6)Lecture MaterialsforAmy Warenda Czura, Ph.D.Suffolk County Community CollegeEastern CampusPrimary Sources for figures and content:Marieb, E. N. Human Anatomy & Physiology 6th ed. San Francisco: Pearson BenjaminCummings, 2004.Martini, F. H. Fundamentals of Anatomy & Physiology 6th ed. San Francisco: PearsonBenjamin Cummings, 2004.Amy Warenda Czura, Ph.D.1SCCC BIO130 Chapter 6 Lecture SlidesSkeletal system components: bones, cartilage, ligaments, other CT thatstabilize the bonesFunctions:1. Support: framework & structure of body2. Storage of minerals and lipidsMinerals: calcium and phosphate (for osmotic regulation, enzyme function, nerve impulses) Yellow marrow = triglycerides3. Blood cell production (all formed elements)red marrow: stem cells → hematopoiesis4. Protection: surround soft tissues5. Leverage for movement (levers upon whichskeletal muscles act)Bone Classification:206 major bones1. Axial skeleton: protection & supportskull, vertebrae, ribs2. Appendicular skeleton: locomotion & manipulation, limbs and limb girdlesAmy Warenda Czura, Ph.D.2SCCC BIO130 Chapter 6 Lecture Slides1. Long bones: longer thanwide, consist of shaft and 2ends, e.g. bones of appendages2. Short bones: approximatelyequal in all dimensions,e.g. carpals, tarsals3. Flat bones: thin, 2 parallelsurfaces, e.g. skull, sternum, ribs, scapula4. Irregular bones: complexshapes, e.g. vertebrae,os coxa5. Sesamoid bones: seed shaped, form in tendon,e.g. patella, total numbercan vary6. Sutural bones: extra bonesin sutures of skullAll bones can be classified by shape:Amy Warenda Czura, Ph.D.3SCCC BIO130 Chapter 6 Lecture SlidesBone Structure-a bone is an organ consisting of many tissuetypes: osseous, nervous, cartilage, fibrousCT, blood, etc.-all bones consist of 2 types of bone tissue1. Compact bone: solid, dense bone, makes upsurfaces and shafts2. Spongy bone/ Cancellous bone: meshy, makes up interior of bones, houses red marrow in spaces-bones are not flat on surface: have projections, depressions, and holes for muscle attachment, blood & nerve supplyAmy Warenda Czura, Ph.D.4SCCC BIO130 Chapter 6 Lecture Slides3. epiphysis = expanded end of bone, surfaceof compact bone, center filled with spongybone with red marrow in spaces (producesblood cells)Long bone structure (handout)1. diaphysis = hollow shaft of compact bone2. medullary (marrow) cavity = center ofdiaphysis, contains yellow marrow (triglycerides for energy reserve)Amy Warenda Czura, Ph.D.5SCCC BIO130 Chapter 6 Lecture Slides5. periosteum = 2 layer covering around outside of bone:outer fibrous layerinner cellular layer6. endosteum = cellularlayer, covers all insidesurfaces4. epiphyseal line or plate =cartilage that marksconnection of diaphysis with epiphysisline- adults, narrow,a.k.a. metaphysisplate - thick, allowsgrowth during childhoodAmy Warenda Czura, Ph.D.6SCCC BIO130 Chapter 6 Lecture Slides7. articular cartilage = hyaline cartilage on end where bone contacts another, no periosteum or perichondriumJoint / Articulation =connection between two bones, surrounded by CTcapsule, lined with synovialmembraneJoint cavity filled with synovial fluid to reducefriction on articular cartilageAmy Warenda Czura, Ph.D.7SCCC BIO130 Chapter 6 Lecture SlidesFlat bone structure-thin layer of spongybone with red marrow betweentwo layers of compact bone-covered byperiosteum andendosteum-site of most hematopoiesisBone Histologybone = osseous tissue, supporting CT-consists of specialized cells in a matrix of fibers and ground substanceAmy Warenda Czura, Ph.D.8SCCC BIO130 Chapter 6 Lecture SlidesCharacteristics of bone1. dense matrix packed with calcium salts2. osteocytes in lacunae3. canaliculi for exchange of nutrients & waste4. two layer periosteum, covers bone except atarticular surfacesMatrix - 98% of bone tissue1/3 = osteoid; organic part: collagen fibers+ ground substance, tough & flexible2/3 = densely packed crystals ofhydroxyapatite (calcium salts, mostly calcium phosphate), hard but brittleCells - only 2% of bone (handout)1. Osteocytes = mature bone cells-no cell division-located in lacunae betweenlayers of matrix calledlamellae-canaliculi link lacunae toeach other and blood supplyAmy Warenda Czura, Ph.D.9SCCC BIO130 Chapter 6 Lecture Slides-osteocytes linked to eachother via gap junctions oncell projections in canaliculi:allow exchange of nutrientsand wastes-osteocytes function to maintain protein and mineral content of matrix-can also participate in bone repair: become active when broken free of lacuna2. Osteoblasts-perform osteogenesis =-produce osteoid (organiccomponents of matrix)-promote deposit of calciumsalts which spontaneouslyform hydroxyapatite-once enclosed in lacuna by matrix, osteoblastdifferentiates into osteocyte and no longerproduces new matrix-bone fracture frees osteocytes which revert toosteoblasts to produce matrix againAmy Warenda Czura, Ph.D.10SCCC BIO130 Chapter 6 Lecture Slides3. Osteoprogenitor cells(mesenchymal cells)-bone stem cell that producesdaughters that becomeosteoblasts for repair andgrowth-located in endosteum and innerperiosteum4. Osteoclasts-large, multinuclear-derived from monocytes(macrophages)-perform osteolysis =-digest and dissolve bone matrix, release minerals for use in blood, or recycling during bone remodelingAmy Warenda Czura, Ph.D.11SCCC BIO130 Chapter 6 Lecture SlidesStructure of compact bone(handout)-consists of osteons:parallel to surface-each osteon aroundcentral canal:contains blood vesselsand nerves-perforating canalsperpendicular to osteonsconnecting osteons-osteon built of layers of matrix secreted byosteoblasts-each layer = concentric lamella-osteocytes located in lacunae between lamellae-osteocytes connected to neighboring cells andcentral canal via canaliculi-interstitial lamellae fill spaces betweenosteonsAmy Warenda Czura, Ph.D.12SCCC BIO130 Chapter 6 Lecture Slides-circumferential lamellae runperimeter inside and out incontact with endosteumand periosteum-compact bone designed toreceive stress from onedirection-very strong parallel toosteons-weak perpendicular toosteonsStructure of spongy bone-lamellae = meshwork called trabeculae(no osteons)-red marrow fillsspaces aroundtrabeculae-osteocytes inlacunae linkedby canaliculi-no direct blood supply (no central canals)Amy Warenda Czura, Ph.D.13SCCC BIO130 Chapter 6 Lecture Slides-nutrients diffuse into canaliculi in trabeculaefrom red marrow-spongy bone makes up low stress bones, or areas of bone where