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Coach Murray
Osseous Tissue & Bone Structure Ch 6
Classify bones according to shape & internal tissues
Identify bone markings and significance of each type
Identify the cell types in bone and their functions.
Compare structure and function of compact bone and spongy bone
Compare the mechanisms of intramembranous ossification and endochondral ossification
Objectives
Describe the remodeling and homeostatic mechanisms of the skeletal system
Discuss the relationship of nutrition, hormones, exercise, and aging on bone development and on the skeletal system
Describe the types of fractures and explain how they heal
Objectives
Structural Support – a framework for attachment of soft tissues and organs
Storage of minerals – Ca, PO4
Storage of lipids – in yellow marrow Blood cell production – in red marrowProtection – skull, vertebrae, pelvis, ribsLeverage – change magnitude/direction of
force of muscles
I. Skeletal System Functions pg 180
A. Six Categories of Bones by shape1. Long – arms, bones, hands/feet, fingers/toes2. Flat – roof of skull, sternum, ribs, scapula3. Sutural (Wormian) – small, flat irregular in
skull w/ borders like a jigsaw puzzle4. Irregular – vertebrae, pelvis, some in skull5. Short – small and boxy, tarsal and carpal
bones6. Sesamoid – sesame seed shaped, form near
joints of knees, hands, and feet – i.e. patella
II. Gross Anatomy of Bones
B. Bone Markings (Surface features of) – see Table 6-1 pg 182
Elevations/Projections: process, ramusTendon/Ligament attachment: trochanter,
tuberosity, tubercle, crest, line, spineArticulation: head, neck, condyle, trochlea,
facetDepressions: fossa, sulcus Openings: foramen, canal, fissure,
sinus/antrum
II. Gross Anatomy of Bones
C. Bone Structure pg 183 – of long boneDiaphysis – extended/expanded tubular shaft w/wall of dense/compact bone (cortex)Epiphysis – at the ends of diaphysis, consists largely of cancellous (spongy )boneMetaphysis – narrow zone b/w each epiphysis and the diaphysis
II. Gross Anatomy of Bones
C. Bone Structure pg 183 (continued) 1. Long bone – a diaphysis (shaft) with an epiphysis at each end w/a metaphysis b/w them.Compact bone surrounds marrow cavity (medullary) and epiphyses are made cancellous bone (spongy).Note: Spongy bone is an open network of struts and plates with a cortex of compact bone.
2. Flat boneCompact bone surrounds diploe (spongy), marrow present, no marrow cavity
II. Gross Anatomy of Bones
Bone is - Osseous tissue is a supporting connective tissue with a solid matrix and ensheathed by a periosteum.
A. Bone Matrix basics: Osteocytes: mature bone cells that maintain
matrixLacunae: pockets which house osteocytes Canaliculi: passageways through matrixPeriosteum: superficial layer of compact bone
w/fibrous outer layer and cellular inner layer
III. Bone Histology
B. The Matrix of Bone: - pg 184Ca3(PO4)2 – 66% by mass
Are hard, inflexible, withstand compressionInteracts w/ Ca(OH)2 to make crystals of
hydroxyapatiteHydroxyapatite also contains CaCO3, Na, Mg, F
Collagen fibers – 31% by massFlexible, twist, bend, do not compressProvide framework on which hydroxyapatite
crystals formStronger than steel w/subject to tension (pull)
Cells of bone – 2%
III. Bone Histology
C. The Cells of Bone - structure and function of each
4 kinds of cells1) Osteocyte
Structure: housed in a lacuna sandwhiched b/w layers called lamellae. Canaliculi connect lamellae w/each other and central canal
Functions (2):Maintain protein and mineral content of matrixRepair damaged bone by converting to osteoblasts
or osteoprogenitor cells
III. Bone Histology
C. Cells of Bone - structure and function of each
4 kinds of cells2) Osteblasts
Structure: immature osteocyteFunction: perform osteogenesis by converting
osteoid to bone. Make and releasing proteins and other organic compounds into matrix, once surrounded they become osteocytes. This is bone buildingActivity is constant, is increased w/exercise
III. Bone Histology
C. The Cells of Bone - structure and function of each
4 kinds of cells3) Osteoprogentior cells
Structure: type of stem cells which make osteoblasts. Found in 3 places: Cellular layer of periosteumendosteum (marrow cavities lining)Lining of passageways containing blood vessels
Function: Repair fractures/breaks in bone
III. Bone Histology
C. The Cells of Bone - structure and function of each
4 kinds of cells4) Osteoclasts (not related osteoprogenitor cells)Structure: big multinucleated cells Function: osteolysis - secrete acid and
proteolytic enzymes to dissolve the matrix and release stored minerals. Regulates Ca & PO4
in body fluidsOpposite to activity of osteoblasts
III. Bone Histology
Structure Described:Haversian system (or osteon) is basic functional
unit of compact bone arranged in concetric layers around the Haversion canal (or central canal) -
Structure: house blood vessels, run parallel to bone surface
Function: supply blood to osteonsOther Info: Canals of Volkmann (perforating canals) –
Structure: house blood vessels, run perpendicular to bone surface
Function: supply blood to osteons of deeper in bone and marrow cavity
D. Structure of Compact Bone pg 185
Structure Described:So the lamellae of each osteon forms nested
cylinders around central canal3 kinds of lamellae
Concentric lamellae – surround central canal, collagen forms a spiral, canaliculi interconnect lacunae of the osteon w/one another and w/the central canal
Interstitial lamellae – space b/w osteons, being recycled by osteoclasts
Circumferential lamellae – outer and inner surfaces of bone so they are covered in periosteum and endosteum
D. Structure of Compact Bone pg 185
D. Structure of Compact Bone pg 185 – source
Unlike compact bone, lamellae present but is not arranged in osteons
Matrix (description of): Made of trabeculae – branched, open network
of thin struts and platesNo capillaries/venules, nutrients get to
osteocytes via diffusion along canaliculi openings
Red marrow b/w trabeculae has blood vessels to deliver nutrients and remove osteocyte wastes
E. Structure of Spongy Bone pg 185
Located of little stress or where stress is multidirectional
Is lighter than compact, makes skeleton lighter
2 kinds of marrow:Red bone marrow:
Location: epiphyses of long bones, interior of ilium/sternum
Function: makes red blood cellsYellow
Location: Function:
F. Structure of Spongy Bone pg 185
Periosteum Location: wraps superficial layer of compact
bones except at jointsStructure: outer layer is fibrous, inner is
cellularCollagen fibers are continous w/bone, joint
capsules, and attached tendons and ligaments providing stronger attachment
Functions: 1) isolates bone from surrounding tissues2) provides route for circulatory/nervous supply3) participates in bone growth/repair
G. The Periosteum and Endosteum pg 188
Endosteum– location: lines marrow cavity, covers the
trabeculae of spongy bone, lines inner surfaces of central canals
- functions: 1) aid in growth, repair, remodeling
structure: single, incomplete layer of osteoprogenitor cells that cover the bone matrixExposed areas osteoclasts and osteoblasts can
remove/deposit matrix
G. The Periosteum and Endosteum pg 188
Ossification – replacing tissues with bone during bone formation
Calcification – deposition of calcium salts which occurs during ossification
2 kinds of ossificationA. Endochondral ossification B. Intramembranous ossification
IV. Bone Formation and Growth pg 189
A. Endochondral ossification – bone replaces existing cartilage
B. Intramembranous ossification – bone develops from mesenchyme or fibrous connective tissue
C. The Blood and Nerve Supplies3 major sets and where they provide blood to:
1. nutrient artery and vein - diaphysis2. metaphyseal vessels – ephiphyseal cartilage3. periosteal vessels – superficial osteons of shaft
IV. Bone Formation and Growth pg 189
Remodeling – is bone maintenance – is the recycling and renewal of organic and mineral compounds of bone matrix
Requirements for osteogenesis:Minerals in diet : Ca, PO4 , Mg, F, Fe, othersVitamins: A, C, B12, KHormones: Calcitonin and parathyroid
hormone
V. Dynamic Nature of Bone pg 194
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