Chapter 6INTRODUCTIONChapter 6 The Skeletal System:Bone TissueFunctions of BoneAnatomy of a Long BoneSlide 6Histology of BoneHISTOLOGY OF BONE TISSUEbone cells.(Figure 6.2)Cells of BoneSlide 11Matrix of BoneCompact BoneCompact or Dense BoneHistology of Compact BoneSpongy BoneThe Trabeculae of Spongy BoneBlood and Nerve Supply of BoneBONE FORMATIONIntramembranousIntramembranous Bone FormationIntramembranous Bone Formation (cont.)Slide 23EndochondrialEndochondral Bone FormationSlide 26Slide 27Bone ScanBONE GROWTHGrowth in LengthBone Growth in LengthZones of Growth in Epiphyseal PlateGrowth in ThicknessBone Growth in WidthFactors Affecting Bone GrowthHormonal AbnormalitiesBONES AND HOMEOSTASISBone RemodelingSlide 39Fracture and Repair of BoneFracture & Repair of BoneFracturesSlide 43Slide 44Repair of a FractureSlide 46Slide 47Calcium Homeostasis & Bone TissueHormonal InfluencesEXERCISE AND BONE TISSUEDevelopment of Bone TissueDevelopmental AnatomyAGING AND BONE TISSUEOsteoporosisDisorders of Bone OssificationSlide 56Principles of Human Anatomy and Physiology, 11e 1Chapter 6The Skeletal System: Bone TissueLecture OutlinePrinciples of Human Anatomy and Physiology, 11e 2INTRODUCTION •Bone is made up of several different tissues working together: bone, cartilage, dense connective tissue, epithelium, various blood forming tissues, adipose tissue, and nervous tissue.•Each individual bone is an organ; the bones, along with their cartilages, make up the skeletal system.Principles of Human Anatomy and Physiology, 11e 3Chapter 6The Skeletal System:Bone Tissue•Dynamic and ever-changing throughout life•Skeleton composed of many different tissues–cartilage, bone tissue, epithelium, nerve, blood forming tissue, adipose, and dense connective tissuePrinciples of Human Anatomy and Physiology, 11e 4Functions of Bone•Supporting & protecting soft tissues•Attachment site for muscles making movement possible•Storage of the minerals, calcium & phosphate -- mineral homeostasis •Blood cell production occurs in red bone marrow (hemopoiesis)•Energy storage in yellow bone marrowPrinciples of Human Anatomy and Physiology, 11e 5Anatomy of a Long Bone•diaphysis = shaft•epiphysis = one end of a long bone•metaphyses are the areas between the epiphysis and diaphysis and include the epiphyseal plate in growing bones.•Articular cartilage over joint surfaces acts as friction reducer & shock absorber•Medullary cavity = marrow cavityPrinciples of Human Anatomy and Physiology, 11e 6Anatomy of a Long Bone•Endosteum = lining of marrow cavity•Periosteum = tough membrane covering bone but not the cartilage –fibrous layer = dense irregular CT–osteogenic layer = bone cells & blood vessels that nourish or help with repairsPrinciples of Human Anatomy and Physiology, 11e 7Histology of Bone•A type of connective tissue as seen by widely spaced cells separated by matrix•Matrix of 25% water, 25% collagen fibers & 50% crystalized mineral salts•4 types of cells in bone tissuePrinciples of Human Anatomy and Physiology, 11e 8HISTOLOGY OF BONE TISSUE•Bone (osseous) tissue consists of widely separated cells surrounded by large amounts of matrix.•The matrix of bone contains inorganic salts, primarily hydroxyapatite and some calcium carbonate, and collagen fibers.•These and a few other salts are deposited in a framework of collagen fibers, a process called calcification or mineralization.–The process of calcification occurs only in the presence of collagen fibers.–Mineral salts confer hardness on bone while collagen fibers give bone its great tensile strength.Principles of Human Anatomy and Physiology, 11e 9bone cells.(Figure 6.2)1. Osteogenic cells undergo cell division and develop into osteoblasts.2. Osteoblasts are bone-building cells.3. Osteocytes are mature bone cells and the principal cells of bone tissue.4. Osteoclasts are derived from monocytes and serve to break down bone tissue.Principles of Human Anatomy and Physiology, 11e 10Cells of Bone•Osteoprogenitor cells ---- undifferentiated cells –can divide to replace themselves & can become osteoblasts–found in inner layer of periosteum and endosteum•Osteoblasts--form matrix & collagen fibers but can’t divide•Osteocytes ---mature cells that no longer secrete matrix•Osteoclasts---- huge cells from fused monocytes (WBC)–function in bone resorption at surfaces such as endosteumPrinciples of Human Anatomy and Physiology, 11e 11Cells of BoneOsteoblasts Osteocytes OsteoclastsPrinciples of Human Anatomy and Physiology, 11e 12Matrix of Bone•Inorganic mineral salts provide bone’s hardness–hydroxyapatite (calcium phosphate) & calcium carbonate•Organic collagen fibers provide bone’s flexibility–their tensile strength resists being stretched or torn–remove minerals with acid & rubbery structure results•Bone is not completely solid since it has small spaces for vessels and red bone marrow–spongy bone has many such spaces–compact bone has very few such spacesPrinciples of Human Anatomy and Physiology, 11e 13Compact Bone•Compact bone is arranged in units called osteons or Haversian systems (Figure 6.3a).•Osteons contain blood vessels, lymphatic vessels, nerves, and osteocytes along with the calcified matrix.•Osteons are aligned in the same direction along lines of stress. These lines can slowly change as the stresses on the bone changes.Principles of Human Anatomy and Physiology, 11e 14Compact or Dense Bone•Looks like solid hard layer of bone•Makes up the shaft of long bones and the external layer of all bones •Resists stresses produced by weight and movementPrinciples of Human Anatomy and Physiology, 11e 15Histology of Compact Bone•Osteon is concentric rings (lamellae) of calcified matrix surrounding a vertically oriented blood vessel •Osteocytes are found in spaces called lacunae•Osteocytes communicate through canaliculi filled with extracellular fluid that connect one cell to the next cell•Interstitial lamellae represent older osteons that have been partially removed during tissue remodelingPrinciples of Human Anatomy and Physiology, 11e 16Spongy Bone•Spongy (cancellous) bone does not contain osteons. It consists of trabeculae surrounding many red marrow filled spaces (Figure 6.3b).•It forms most of the structure of short, flat, and irregular bones, and the epiphyses of long bones.•Spongy bone tissue is light and supports and protects the red bone marrow.Principles of Human Anatomy