The Skeletal The Skeletal SystemSystem
Supports the body
Protects soft organs
Allows movement due to attached skeletal muscles
Stores minerals and fats
Blood cell formation
The Skeletal SystemThe Skeletal SystemParts of the skeletal systemParts of the skeletal system– Bones (skeleton)Bones (skeleton)– JointsJoints– CartilagesCartilages– LigamentsLigaments
Two subdivisions of Two subdivisions of the skeletonthe skeleton– Axial skeletonAxial skeleton
skull, spine, ribs skull, spine, ribs– Appendicular skeletonAppendicular skeleton
shoulders, arms shoulders, arms hips, legs hips, legs
Bones of the Bones of the Human BodyHuman Body
The adult skeleton The adult skeleton has 206 boneshas 206 bones
Two basic types of Two basic types of bone tissuebone tissue
– Compact boneCompact bone
– Spongy boneSpongy bone
Classification of Bones by shapeClassification of Bones by shape
Long bonesLong bones– Typically longer than Typically longer than
they are widethey are wide– Have a shaft with Have a shaft with
heads at both endsheads at both ends– Contain mostly Contain mostly
compact bonecompact bone– ExampleExample::
FemurFemur
HumerusHumerus
Shaft
Classification of Bones by ShapeClassification of Bones by ShapeShort bonesShort bones
– Generally cube-shapeGenerally cube-shape– Contain mostly Contain mostly
spongy bonespongy bone– ExampleExample::
CarpalsCarpals
TarsalsTarsals
Classification of Bones by ShapeClassification of Bones by ShapeFlat bonesFlat bones
– Thin, flattened, and Thin, flattened, and usually curvedusually curved
– Two thin layers of Two thin layers of compact bone compact bone surround a layer of surround a layer of spongy bonespongy bone
– ExampleExample: : SkullSkullRibsRibsSternumSternum
Classification of Bones by ShapeClassification of Bones by Shape
Irregular bonesIrregular bones– Irregular shapeIrregular shape– Do not fit into other Do not fit into other
bone classification bone classification categoriescategories
– ExampleExample: :
Vertebrae Vertebrae
Hip bonesHip bones
Anatomy of a Long BoneAnatomy of a Long Bone
DiaphysisDiaphysis– ShaftShaft– Composed of compact Composed of compact
bonebone
EpiphysisEpiphysis – Ends of the boneEnds of the bone– Composed mostly of Composed mostly of
spongy bonespongy bone
Anatomy of a Long BoneAnatomy of a Long Bone
PeriosteumPeriosteum– Outside covering of Outside covering of
the diaphysis (shaft)the diaphysis (shaft)– Fibrous connective Fibrous connective
tissue membranetissue membrane
Cartilage = Connective TissueCartilage = Connective Tissue
CartilageCartilage– Covers the external surface of long bonesCovers the external surface of long bones– Made of “Made of “hyaline cartilagehyaline cartilage””– Decreases friction at joint surfacesDecreases friction at joint surfaces
When you’re When you’re growing….growing….
Epiphyseal plateEpiphyseal plate– Flat plate of hyaline Flat plate of hyaline
cartilage seen in cartilage seen in young, growing bone young, growing bone (a.k.a. = growth plate)(a.k.a. = growth plate)
Epiphyseal lineEpiphyseal line– Remnant of the Remnant of the
epiphyseal plateepiphyseal plate– Seen in adult bonesSeen in adult bones
Anatomy of a Long BoneAnatomy of a Long BoneMedullary cavityMedullary cavity
– Cavity inside of the Cavity inside of the shaftshaft
– Contains yellow Contains yellow marrow (mostly fat) in marrow (mostly fat) in adults. With severe adults. With severe blood loss, can be blood loss, can be converted to red converted to red marrowmarrow
– Contains red marrow Contains red marrow (for blood cell (for blood cell formation) in infantsformation) in infants