the skeletal system
Post on 23-Feb-2016
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Major Functions of the Skeletal System
Shape and support for the bodyProtects inner organs
Skull – brainRibs – heart and lungs
Muscles attach to bonesCreates red blood cells, white blood
cells, and platelets in the marrowStores calcium and phosphorus
Bone Structure Not completely smooth
Bumps, rough edges, pits, holesCovered by periosteum
Tough, tight fitting membraneContains blood vessels, allows oxygen to reach inner bone, allows for wastes to leave
Bone MarrowFatty tissue found within bonesProduces red blood cells
2,000,000/secProduces white blood cells
Not as fast as redProduces platelets
CartilageThick, smooth layer of tissueCovers ends of bonesDoes not contain blood vessels or
mineralsAbsorbs shock, reduces frictionPainful when it wears away
Bones rub togetherArthritis develops
Bone DevelopmentOsteoblasts
Bone forming cellsDeposit calcium and phosphorus (hardness)
OsteoclastsCells that break down bone (normal)
Bones are always being broken down and reformed
JointsWhere two or more bones meetHeld together by ligaments
Tough bands of tissueMany joints held together by more
than one ligamentEx. knee
Types of JointsImmovable joints
Allow little or no movementMovable joints
Allow wide range of movements
Movable JointsPivot
One bone rotates in the ring of another
Ex. Turning your head http://www.dkimages.com/discover/previews/940/672504.JPG
Ball and socketOne bone has a cup like cavity
Another bone has a rounded end that fits inside
Ex. Hips, shoulders http://archive.ncsa.uiuc.edu/Cyberia/VideoTestbed/
Projects/NewAnatomy/images/bshoulder.JPG
HingeBack and forth movement (like hinges on a door)
Less flexible, more stable
Ex. Elbows, knees, fingers http://www.dkimages.com/discover/previews/940/672450.JPG
GlidingOne bone slides
over anotherBack and forth
motionMost frequently
usedEx. Wrists, ankles,
vertebraehttp://www.teachpe.com/images/anatomy/gliding_joint.jpg
Bone ShapesShort –toes
(phalanges)Small precise
movementsSupport weight
Long – legs & arms, length of fingersStrongSupport weightAllow movement
Bone ShapesFlat – ribs, sternum
& shoulderProtect organs
Irregular – vertebrae & inner earSupport - vertebraeHearing – inner ear
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