The Skeletal SystemThe Skeletal System

Stephen Pou & Rahul RaiStephen Pou & Rahul Rai

Human BiologyHuman Biology

6-Wolsko6-Wolsko

Skeletal System OverviewSkeletal System Overview

Consists of 206 Consists of 206 bones divided into bones divided into two main categories:two main categories:– Axial SkeletonAxial Skeleton– Appendicular SkeletonAppendicular Skeleton

Has major functionsHas major functionsMade of different Made of different types of bonestypes of bonesBones are about 13% Bones are about 13% of total body weightof total body weight

FunctionsFunctions

SupportSupport keeps the keeps the body up and gives it body up and gives it shape and formshape and form

ProtectionProtection protects protects organs from damageorgans from damage

MovementMovement gives gives the body the ability to the body the ability to move move

FunctionsFunctions

StorageStorage stores stores minerals such as minerals such as calcium and ironcalcium and ironBlood Cell Blood Cell ProductionProduction makes makes the red blood cellsthe red blood cellsEndocrine Endocrine RegulationRegulation regulates fat and regulates fat and blood sugar blood sugar depositiondeposition

Axial SkeletonAxial Skeleton

Made up of the Made up of the vertebral column, vertebral column, thoracic cage, and thoracic cage, and skullskull

Has 80 bones in totalHas 80 bones in total

Transmits weight of Transmits weight of upper body to lower upper body to lower body.body.

Appendicular SkeletonAppendicular Skeleton

Has a total of 126 Has a total of 126 bonesbonesConsists of the upper Consists of the upper and lower extremities and lower extremities and the pelvic and and the pelvic and pectoral girdlespectoral girdlesDistributes weight Distributes weight from head and torso from head and torso evenly throughout evenly throughout bodybody

Types of BonesTypes of Bones

Long:Long:– Used to support body weightUsed to support body weight– Composed of mostly compact Composed of mostly compact

bone with little marrowbone with little marrow– Found in the legs and armsFound in the legs and arms

Short:Short:– Thin layer of compact bone Thin layer of compact bone

with mostly marrowwith mostly marrow– Found in wrists and anklesFound in wrists and ankles

Flat:Flat:– Two thin layers of compacts Two thin layers of compacts

bone with marrow in the bone with marrow in the middlemiddle

– Found in skull and sternumFound in skull and sternum

Types of BonesTypes of Bones

Irregular:Irregular:– Don’t have a specific Don’t have a specific

shapeshape– Usually have even amount Usually have even amount

of marrow and compact of marrow and compact bonebone

– Found in hips and spineFound in hips and spine

Sesamoid:Sesamoid:– The bones embedded in The bones embedded in

tendonstendons– Increases leverage of Increases leverage of

musclemuscle– Found in wrists and anklesFound in wrists and ankles

Bone CompositionBone Composition

Made up of two types of Made up of two types of material:material:– Compact/dense boneCompact/dense bone

Forms the outside of boneForms the outside of bone

Very strongVery strong

Formed by stacked layers Formed by stacked layers of tissueof tissue

– Spongy boneSpongy boneInside of bone known as Inside of bone known as the marrowthe marrow

Light and porousLight and porous

Absorb stress from Absorb stress from compact bonecompact bone

Bone CartilageBone Cartilage

Cartilage is the Cartilage is the connective tissue connective tissue between bonesbetween bonesThere are 3 different There are 3 different types:types:– FirbroFirbro strongest type of strongest type of

cartilage found in high cartilage found in high stress areasstress areas

– HyalineHyaline strong but strong but flexible cartilage that flexible cartilage that reduces friction and eases reduces friction and eases bone movementbone movement

– ElasticElastic not very strong not very strong but really flexible; provide but really flexible; provide flexibility in low stress flexibility in low stress areasareas

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Tendons, Ligaments & JointsTendons, Ligaments & Joints

All three are All three are connections of bones connections of bones and are made of and are made of hyaline cartilagehyaline cartilage

Keep bones together Keep bones together and provide and provide movement and movement and flexibilityflexibility

Tendons, Ligaments & JointsTendons, Ligaments & Joints

TendonsTendons– Connects Connects bonebone to to muscle muscle – Provides the expand and contract that the muscle Provides the expand and contract that the muscle

does in order to movedoes in order to move

LigamentsLigaments– Connects Connects bonebone to to bonebone– controls range of motion and stabilization in the jointscontrols range of motion and stabilization in the joints

JointsJoints– Formally known as an articulationFormally known as an articulation– With the help of ligaments, give bone connections With the help of ligaments, give bone connections

movements and range of motionmovements and range of motion

Tendons, Ligaments & JointsTendons, Ligaments & Joints

There are different types There are different types of joints that are used for of joints that are used for different purposes and different purposes and classified by their type of classified by their type of movement:movement:– Ball and socketBall and socket– HingeHinge– Condyloid- a joint that Condyloid- a joint that

provides angular motionprovides angular motion– PivotPivot– Gliding (Plane)Gliding (Plane)– Saddle Saddle

OssificationOssification

Ossification- the process in which bones are Ossification- the process in which bones are made made – This is done by connective tissue turning into bone or This is done by connective tissue turning into bone or

bone-like materialbone-like material– Done by two different processes:Done by two different processes:

Endochondral OssificationEndochondral Ossification

Intramembranous OssificationIntramembranous Ossification

– The difference between these two processes are that The difference between these two processes are that endochondral is when your body matures and endochondral is when your body matures and intramembranous is when a human is being formed intramembranous is when a human is being formed inside of a whom.inside of a whom.

OssificationOssification

Endochondral OssificationEndochondral Ossification gradual gradual transformation of cartilage into bonetransformation of cartilage into bone– Happens as osteoblasts turn into osteocytes which Happens as osteoblasts turn into osteocytes which

are a hardened, mature form of osteoblastsare a hardened, mature form of osteoblasts

OssificationOssification

Intramembranous Intramembranous OssificationOssification the the development of development of embryonic cells into embryonic cells into bonebone– The embryonic cells The embryonic cells

involved develop into involved develop into connective tissue then connective tissue then blood and bonesblood and bones

OsteoporosisOsteoporosisWhen, for a variety of reasons, a person’s Bone When, for a variety of reasons, a person’s Bone Mineral Density (BMD) decreases and is below the Mineral Density (BMD) decreases and is below the normal amountnormal amountReasons for OsteoporosisReasons for Osteoporosis– AgeAge– Lack of calciumLack of calcium– Low estrogen levelsLow estrogen levels

Some symptoms include severe back pain, height loss, Some symptoms include severe back pain, height loss, frequent bone fracturefrequent bone fractureCures include:Cures include:– Calcium pillsCalcium pills– Menopausal hormone therapyMenopausal hormone therapy– Prescribed medication Prescribed medication

OsteoarthritisOsteoarthritis

The breakdown of cartilage in joints causing The breakdown of cartilage in joints causing inflammationinflammationCauses include:Causes include:– HeredityHeredity– ObesityObesity– Injury to a jointInjury to a joint– Overuse of a jointOveruse of a joint

Symptoms are soreness and aching, inflammation, bony Symptoms are soreness and aching, inflammation, bony enlargements on jointenlargements on jointTo cure Osteoarthritis:To cure Osteoarthritis:– ExerciseExercise– Avoid use of joint (crutches, wheelchair, bandage)Avoid use of joint (crutches, wheelchair, bandage)– Temperature treatmentsTemperature treatments– Prescribed medicationPrescribed medication

Rheumatoid ArthritisRheumatoid Arthritis

Chronic arthritis usually affecting both sides of Chronic arthritis usually affecting both sides of the body (ex. Both wrists or both ankles)the body (ex. Both wrists or both ankles) A person could get RA genetically, by being A person could get RA genetically, by being obese, suffering an injury, or overuse of a jointobese, suffering an injury, or overuse of a joint Symptoms include:Symptoms include:– Joint painJoint pain– SwellingSwelling– FatigueFatigue

Methods to totally cure RA do not exist but one Methods to totally cure RA do not exist but one could take could take Disease-Modifying Anti-could take could take Disease-Modifying Anti-Rheumatic Drugs (DMARDs) to slow down the Rheumatic Drugs (DMARDs) to slow down the progression of RAprogression of RA