the skeletal system structure and function of bone organization of the skeleton joints
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The skeletal system
Structure and function of bone
Organization of the skeleton
Joints
Functions of bone (skeleton)
Support and protection
Blood cell formation
Mineral storage (calcium especially)
Site for muscle attachmentbody movement
Bones classified by shape: long, short, flat, irregular, round
Bone enclosed in periosteum, which is continuouswith tendons and ligamentsblood vessels in periosteum
Epiphysis- endsspongy bone contains red marrowcompact bone, articular cartilage
Diaphysis- middlecompact bonemedullary cavity- contains yellow marrow (fat)lined with endosteum (squamous epithelium)
Compact boneosteocytes within lacunaearranged in concentric circles called lamellae
This surround a central canal; complex is calledHaversian system
Canaliculi connect osteocytes to central canal andto each other
Prenatal developmentskeleton is mostly cartilaginous
Cartilage cells and then osteoblasts start todeposit minerals
Cartilaginous disk (epiphyseal disk) remainsin epiphysis
Cells eventually stop dividing
Adults continually break down and build up bone
Osteoclasts remove damaged cells and releasecalcium into blood
Osteoblasts remove calcium from blood and buildnew matrix. They become trappedosteoclasts
Types of bone breaks
Simple- skin is not piercedCompound- skin is piercedComplete- bone is broken in halfPartial- broken lengthwise but not into two
partsGreenstick- incomplete break on outer arcComminuted- broken into several piecesSpiral- twisted
Fracture repair
Hematoma- blood clot in space between edgesof break
Fibrocartilage callus- begins tissue repair
Bony callus- osteoblasts produce trabeculae(structural support) of spongy bone andreplace fibrocartilage
Remodeling- osteoblasts build new compact bone,osteoclasts build new medullary cavity
Axial skeletonskull (cranium and facial bones) hyoid bone (anchors tongue and muscles
associated with swallowing) vertebral column (vertebrae and disks) thoracic cage (ribs and sternum)
Appendicular skeletonpectoral girdle (clavicles and scapulae)upper limbs (arms)pelvic girdle (coxal bones, sacrum, coccyx)lower limbs (legs)
posterior viewp. 135
Axial skeleton supports and protects organsof head, neck and trunk
Appendicular skeleton- bones of limbs and bones that anchor them to the axialskeleton
Articulation- where joints are formed
22 bones in skull6 in middle ears1 hyoid bone26 in vertebral column25 in thoracic cage
4 in pectoral girdle60 in upper limbs60 in lower limbs2 in pelvic girdle
206 bones in all
The skull
8 sutured bones in craniumFacial bones: 13 sutured bones, 1 mandible
Craniumencases brainattachments for musclessinuses
Allows forgrowth
Vertebral column
7 cervial vertebrae12 thoracic5 lumbar1 sacrum (5 fused 1 coccyx (4 fused)
Vertebrae vary in size and morphology
Thoracic cageribsthoracic vertebraesternumcostal cartilages
True ribs are directly attached to the sternum(first seven pairs)Three false ribs are joined to the 7th ribTwo pairs of floating ribs
Clavicles and scapulae
Help brace shouldersAttachment sites for muscles
Bones of upper limb
Humerus (upper arm)Radius; ulnaCarpals, metacarpals, phalanges
Bones of lower limb
FemurPatellaTibia, fibulaTarsals, metatarslas, phalanges