Reading:IntroductiontoSkeletalSystem
Directions:Readandannotatethepassagesbelow.Useyourpriorknowledgeofthe
skeletalsystemtoidentifywhichstatementisTrueorFalse.WriteTRUEorFALSEin
theblanksprovided.
Insideeverypersonisaskeleton,asturdyframeworkof206bones.Theskeleton
protectsthebody'sorgans,supportsthebody,andprovidesattachmentpointsfor
musclestoenablebodymovement.Bonesalsoproducebloodcellsandactasa
storagesiteformineralssuchascalciumandphosphorus.
1. _________Theskeletalsystemsupportsandprotectsseveraloftheotherbody
systems.
2. _________Thehumerusisthelongestboneinthebody.
3. _________Therearethreebonesineachdigitofthehand.
Allhumansarebornwithover300bones.Butsomebones,suchasthoseintheskullandlowerspine,
fuse(jointogether)duringgrowth,therebyreducingthenumber.Theskeletalsystemismadeupofliving
material,withnetworksofbloodvesselsrunningthroughout.Livingmatureboneisabout60percent
calciumcompoundsandabout40percentcollagen(afibrousprotein).Boneisstrong,hard,andslightly
elastic.Althoughmaturebonesconsistlargelyofcalcium,mostbonesinthehumanskeletonbeganas
cartilage.Cartilageisatypeofconnectivetissuethatcontainscollagenandelastinfibers.
4. _________Therearefewerbonesinaninfantthanthereareinanadult.
5. _________Onceboneisformedandhardened,itisnotremodeledagain.
6. _________Boneremodelingoccursthroughoutyourlifetime.
7. _________Afterpuberty,bonescontinuetolengthenevenafterfusionofthegrowthplates.
Individualbonesmeetatareascalledjointsandareheldinplacebyconnectivetissue.
Cartilagelinesthesurfaceofmanyjointsandhelpsreducefrictionbetweenbones.
Theconnectivetissueslinkingtheskeletontogetheratthejointsareligamentsand
tendons.Botharemadeupofcollagen,butservedifferentfunctions.Ligaments
connectbonestogetherandhelppreventdislocatedjoints.Tendonsconnectboneto
muscle.
Boneconsistsofavarietyofveryactive,livingtissuesincludingbonetissue,cartilage,
denseconnectivetissue,blood,andnervoustissue.Themainfunctionsofbonearetoprovidesupport
andprotection,bodymovement,bloodcellformation,andstoreinorganicsalts(mostlycalcium,
magnesium,sodium,andpotassium).
8. _________Thetypeofarthritiscausedbynormalwearandtearofjointsiscalledosteoarthritis.
9. _________Theappendicularskeletonincludestheskull,thevertebralcolumn,andthebonesofthe
chestregion.
10. _________Calcitoninisreleasedfromthethyroidwhenbloodcalciumlevelsarehigh,causing
calciumtobestoredinbone.
11. _________Thescapulaispartoftheaxialskeleton.
AnswerKey
#1–True
#2–False
#3–False
#4–False
Reading:IntroductiontoSkeletalSystem
#5–False
#10–True
#6–True
#11-False
#7-False
#8–True
#9–False