Skeletal tissue and system
Skeletal systemBones and cartilage
Protect organsAllow for motion
Orthopaedics(Orthopedics)Medical specialty for restorative treatment of skeleton and articulations (joints) and associated connective tissue
Skeletal system tissueCartilageBoneDense connective
Skeletal system functionsSupportProtectionMovement (along with attached muscle)Mineral Storage (calcium)Storage and production of blood cell – red marrow (hematopoiesis)Energy storage -yellow marrow
Bone tissue cell types
Osteogenic (osteoprogenitor) cells
From mesenchymeCan proliferate (mitosis)Can differentiateIn periosteum, endosteum and canalicula
OsteoblastsForm boneProduce & secrete organic (collagenous) componentsProduce & secrete mineral salts (hydroxyapatite; calcium phosphate, calcium carbonate)Can no longer divide
OsteocytesMajor cell of bone tissue“Mature” bone cellsMaintain boneTrapped in their own secretions
OsteoclastsReabsorb bone (degrade bone)Critical for remodeling and development and repairLocated on bone surface
Types of bone
Long bone structureDiaphysis – shaft / main portionEpiphysis – endsMetaphysis – btwn dia & epiphysisCartilage – hyaline for shock absorption and friction reductionPeriosteum – dense covering of two layers for growth, repair & attachments
Elastic fibers and blood vesselsOsteogenic, -clast & -blast cells
Long bone structure
Medullary cavity (bone marrow)Within diaphysisYellow bone marrow in
adultsFat and blood cells
Endosteum – lines medullaOsteoblasts and clasts
Compact bone and spongy bone
Compact and spongy bone
Compact bone characteristicsLittle space
Thick in diaphysis
Thin in epiphysis
Protection and support
Compact bone structureRings of bone material - Osteons– Contain osteocytes– Lacunae – space in which osteocytes are trapped– Canaliculi – connect to lacunae, “little canals” for
nutrient and waste distribution– Central canals – lead to perforating canals
Spongy bone
Spongy boneNo true osteonsTrabeculae – irregular thin bone platesRed marrow between trabeculae
Produces blood cells
Osteocyte containing lacunae within trabeculae
Bone FormationIntramembranous Ossification
Formation of bone within fibrous membranesForms flat bones of skull
Endochondral ossificationMost common type of bone formationBone forms from cartilage
Intramembranous Ossification
Intramembranous Ossification
Endochondral Ossification
Endochondral Ossification
Endochondral Ossification
Bone disordersOsteoporosis
Bone disordersOsteomalacia (rickets in children)
Bone disordersOsteomyelitis
Bone disordersOsteoarthritis
Bone disorders
Bone fractures
Bone repair
Calcium Homeostasis
PTH (parathyroid hormone)
Calcitonin
