The Skeletal SystemThe Skeletal System

Formation of BoneFormation of BoneWhen you are developing as a baby, your When you are developing as a baby, your bone starts as cartilage.bone starts as cartilage.

As development continues,As development continues,blood vessels stimulate cartilage and turn blood vessels stimulate cartilage and turn it into potential bone cells.it into potential bone cells.

These potential bone cells are called These potential bone cells are called OSTEOBLASTS!OSTEOBLASTS!

Cells secrete hormones that make the Cells secrete hormones that make the bone harden.bone harden.

OSTEOBLASTSOSTEOBLASTS

Bone StructureBone StructureCOMPACT BONE COMPACT BONE = = Outside layer = Dense, hard Outside layer = Dense, hard bonebone– Supplies oxygen and Supplies oxygen and

nutrients to bone cellsnutrients to bone cells

SPONGY BONESPONGY BONE = Inside = Inside layer layer – Less dense boneLess dense bone– Lots of holes and spaces (like Lots of holes and spaces (like

a sponge)a sponge)

BONE MARROW BONE MARROW = = Innermost layerInnermost layer

Spongy Bone

Bone Marrow

Compact Bone

Bone StructureBone Structure

What is the purpose of bone?What is the purpose of bone?

Framework upon which Framework upon which muscles and organs restmuscles and organs rest

ProtectionProtection

Helps with movement by Helps with movement by linking muscles and bones linking muscles and bones with jointswith joints

Helps the immune systemHelps the immune system

Warehouse for mineralsWarehouse for minerals

Purpose Video

How can bones help your How can bones help your immune system?immune system?

Bone marrow has many Bone marrow has many useful cells!useful cells!– Red marrow produces red blood Red marrow produces red blood

cells which carry oxygen cells which carry oxygen throughout the body.throughout the body.

– Red marrow also produces white Red marrow also produces white blood cells to fight disease!blood cells to fight disease!

– Yellow marrow helps store fats Yellow marrow helps store fats and produces red blood cells and produces red blood cells during major injury.during major injury.

The Skeletal SystemThe Skeletal System

More Bones and Joints!More Bones and Joints!

Lots of Bones!Lots of Bones!

The human skeleton The human skeleton

has has 206206 bones! bones!

These bones are These bones are divided into two divided into two sections on the sections on the skeleton.skeleton.– AxialAxial– AppendicularAppendicular

Axial SkeletonAxial Skeleton

Axial SkeletonAxial Skeleton– Skull and bones Skull and bones

that support itthat support itSkullSkull

Vertebral ColumnVertebral Column

RibsRibs

SternumSternum

AXIAL SKELETONAXIAL SKELETON

Appendicular SkeletonAppendicular Skeleton

APPENDICULARAPPENDICULAR = the = the bottom half!bottom half!– armsarms– legslegs– pelvic girdlepelvic girdle– shouldersshoulders

APPENDICULAR SKELETONAPPENDICULAR SKELETON

Bringing it all together…Bringing it all together…

JOINTS are the hinges that connect JOINTS are the hinges that connect bones to one another.bones to one another.

Most joints are moveable, but…Most joints are moveable, but…

Stationary joints are called fixed joints.Stationary joints are called fixed joints.– Ex: SkullEx: Skull

Joints are held together by LIGAMENTSJoints are held together by LIGAMENTS– Ligaments are tough bands of tissueLigaments are tough bands of tissue

The ends of bones are covered with The ends of bones are covered with cartilage to ensure smooth motion.cartilage to ensure smooth motion.

JOINTSJOINTS

MORE ON JOINTSMORE ON JOINTS

LIGAMENTS LIGAMENTS = Thin bands are tissue that = Thin bands are tissue that connect bone to boneconnect bone to bone

TENDONSTENDONS = Thick bands of tissue that = Thick bands of tissue that connect muscle to bone connect muscle to bone

BURSABURSA = Fluid-filled sac that absorbs = Fluid-filled sac that absorbs shock and prevents bones from rubbing shock and prevents bones from rubbing together.together.

LIGAMENTSLIGAMENTS

TENDONSTENDONS

BURSABURSA

ArthritisArthritis

-itis-itis means inflammation means inflammation

Arthro-Arthro- means joint means joint

ArthritisArthritis, therefore, means…, therefore, means…

More than 100 types of arthritisMore than 100 types of arthritis

About 37 million people have arthritis in About 37 million people have arthritis in the US ~ 1 out of 7 peoplethe US ~ 1 out of 7 people

ArthritisArthritis

Popping Your KnuckelsPopping Your KnuckelsAll joints are surrounded by synovial fluid, a thick, clear liquidAll joints are surrounded by synovial fluid, a thick, clear liquid

Stretching or bending the finger causes the bones of the joint to Stretching or bending the finger causes the bones of the joint to pull apart which causes the connective tissue capsule to stretch pull apart which causes the connective tissue capsule to stretch increasing its volumeincreasing its volume

Increasing the volume decreases the pressure of the synovial Increasing the volume decreases the pressure of the synovial fluid.fluid.

The synovial fluid pressure drops, gases dissolved in the fluid The synovial fluid pressure drops, gases dissolved in the fluid become less soluble, forming bubbles through a process called become less soluble, forming bubbles through a process called cavitationcavitation. .

When the joint is stretched far enough, the pressure in the When the joint is stretched far enough, the pressure in the capsule drops so low that these bubbles burst, producing the capsule drops so low that these bubbles burst, producing the pop that we associate with knuckle cracking. pop that we associate with knuckle cracking.

It takes about 25-30 minutes for the gas to redissolve into the It takes about 25-30 minutes for the gas to redissolve into the joint fluid. During this period of time, your knuckles will not joint fluid. During this period of time, your knuckles will not crack. Once the gas is redissolved, cavitation is once again crack. Once the gas is redissolved, cavitation is once again possible, and you can start popping your knuckles again. possible, and you can start popping your knuckles again.

Damage from Popping KnucklesDamage from Popping KnucklesOnly one in-depth studyOnly one in-depth study

300 people300 people

No correlation between popping knuckles and No correlation between popping knuckles and arthritisarthritis

Problems they did have: soft tissue damage to the Problems they did have: soft tissue damage to the joint capsule and a decrease in grip strengthjoint capsule and a decrease in grip strength

Probably because of the stretching of ligaments Probably because of the stretching of ligaments when creating the poppingwhen creating the popping

Professional Baseball players experience similar Professional Baseball players experience similar effects to their pitching arm effects to their pitching arm

OsteoporosisOsteoporosisOsteoporosis means porous boneOsteoporosis means porous bone

A disease in which bones become less A disease in which bones become less dense and fragile.dense and fragile.

Painless until bone breaksPainless until bone breaks

Can happen in any bone Can happen in any bone

Happens typically in hip, spine, and handHappens typically in hip, spine, and hand

Women are 4 times more likely then menWomen are 4 times more likely then men

10 million people in US – 10 million people in US – – 8 million = women8 million = women– 2 million = men 2 million = men

OsteoporosisOsteoporosis