The musculoskeletal systemThe musculoskeletal systemDr. T.Dr. T.

Why are we looking at these two Why are we looking at these two systems together?systems together?

It is because these two systems work It is because these two systems work together so closely.together so closely.

The skeletal system gives us our The skeletal system gives us our shape, supports our bodies, protects shape, supports our bodies, protects vital organs, and is a reservoir of vital organs, and is a reservoir of important minerals.important minerals.

Muscles provide us with the power Muscles provide us with the power that allows us to move around.that allows us to move around.

Without a skeletal system to provide Without a skeletal system to provide support, our muscles could not support, our muscles could not function!function!

Components of the Musculoskeletal Components of the Musculoskeletal systemsystem

1.1. BonesBones2.2. CartilageCartilage3.3. LigamentsLigaments4.4. TendonsTendons5.5. Skeletal (Striated) muscles.Skeletal (Striated) muscles. Note: There are two other types of Note: There are two other types of

muscle tissue we will learn about, but muscle tissue we will learn about, but they are not considered part of the they are not considered part of the musculoskeletal system.musculoskeletal system.

What are muscles?What are muscles?

Muscles consist of cells and contractile Muscles consist of cells and contractile fibers.fibers.

Muscle work by shortening in length.Muscle work by shortening in length.You have two sets(or more) of muscles You have two sets(or more) of muscles

attached to many of your bones which attached to many of your bones which allow them to move.allow them to move.

There are 630 active muscles in your There are 630 active muscles in your body.body.

Muscles can only pull, they canMuscles can only pull, they can’’t push.t push.

More on muscles.More on muscles.The Three Types of MusclesThe Three Types of Muscles

Type of Muscle Smooth Muscle Cardiac Muscle Skeletal MuscleType of Muscle Smooth Muscle Cardiac Muscle Skeletal MuscleAppearanceAppearance SmoothSmooth StriatedStriated StriatedStriated

Voluntary or Voluntary or InvoluntaryInvoluntary InvoluntaryInvoluntary InvoluntaryInvoluntary VoluntaryVoluntary

FunctionFunction Controls Controls Controls Controls Moves bones.Moves bones.movement ofmovement of contractionscontractions Work in pairs.Work in pairs.internal organsinternal organs of the heartof the heart When one When one

contractscontractsthe other the other relaxes.relaxes.

Attached to bones byAttached to bones bytendons.tendons.

Check for learning.Check for learning.

On the paper provided, answer the On the paper provided, answer the following questions without referring to following questions without referring to your worksheet.your worksheet.

1. What are the 5 components of the 1. What are the 5 components of the musculo-skeletal system?musculo-skeletal system?

2. What are the 3 types of muscle 2. What are the 3 types of muscle tissue?tissue?

BonesBones

Like everything else in your body, your Like everything else in your body, your bones consist of cells.bones consist of cells.

Two types.Two types.Osteoblasts: Cells which build bones.Osteoblasts: Cells which build bones.Osteoclasts: Cells which break down bonesOsteoclasts: Cells which break down bones

To release To release minerals, like minerals, like calcium calcium

How to remember the difference?How to remember the difference?OsteoOsteoBBlasts lasts BBuild uild BBone. 3 Bone. 3 B’’s.s.

Thanks for your support.Thanks for your support.

Without a bones youWithout a bones you’’d be d be floppy like a beanbag. floppy like a beanbag.

Could you stand up? Forget Could you stand up? Forget about it.about it.

Could you walk? No way, Could you walk? No way, man!man!

Without bones youWithout bones you’’d be a d be a puddle of skin and guts on puddle of skin and guts on the floor.the floor.

The job of the bones.The job of the bones.

Your skeleton has several jobs.Your skeleton has several jobs. Some bones, like your Some bones, like your

backbone, provide structure.backbone, provide structure. Other bones, like your skull Other bones, like your skull

and rib cage protect vital and rib cage protect vital organs.organs.

The tiniest bones in your body, The tiniest bones in your body, in the inner ear, help to in the inner ear, help to transmit sound waves to your transmit sound waves to your brain.brain.

So how many bones do we have?So how many bones do we have?

Actually, you have less than Actually, you have less than you once did.you once did.

As a new born, you had over As a new born, you had over 300 bones.300 bones.

As you grew up, many of As you grew up, many of these bones fused together.these bones fused together.

You now have 206 elegant You now have 206 elegant bones in your body.bones in your body.

So how do muscles and bones do So how do muscles and bones do their jobs?their jobs?

With a lot of help.With a lot of help.Along with muscles and bones, you need Along with muscles and bones, you need

joints.joints.Joint provided flexible connections Joint provided flexible connections

between bones. Joints are primarily made between bones. Joints are primarily made up of tissue called ligaments. up of tissue called ligaments.

Tendons attach bone to muscle, ligaments Tendons attach bone to muscle, ligaments attach bone to bone.attach bone to bone.

Types of jointsTypes of joints

Hinge joints: Like in your knee, enable Hinge joints: Like in your knee, enable bones to move back and forth.bones to move back and forth.

Pivot joints: Like in your neck, enable you Pivot joints: Like in your neck, enable you to turn your head around.to turn your head around.

Ball and socket joints: Like in your Ball and socket joints: Like in your shoulder, enable you to move your arms shoulder, enable you to move your arms 360 degrees.360 degrees.

Semi-moveable joints: Like the ones Semi-moveable joints: Like the ones between the vertebrae in your backbone.between the vertebrae in your backbone.

Are bones alive?Are bones alive?

Absolutely. If not, then broken arms and legs Absolutely. If not, then broken arms and legs would never heal.would never heal.

Like all other cells in your body, bone cells need Like all other cells in your body, bone cells need nutrients and oxygen and they produce wastes.nutrients and oxygen and they produce wastes.

When you break a bone, blood clots form to When you break a bone, blood clots form to close the space between the two segements. close the space between the two segements. Osteoblasts the begin the process of depositing Osteoblasts the begin the process of depositing bone to heal the fracture.bone to heal the fracture.

What is bone marrow?What is bone marrow?

Many of your larger bones are hollow. Many of your larger bones are hollow. Being hollow helps to reduce the weight of Being hollow helps to reduce the weight of

your bones.your bones. In the center of these bones, bone marrow In the center of these bones, bone marrow

makes new red and white blood cells.makes new red and white blood cells.So it turns out that your bones actually So it turns out that your bones actually

make blood! How cool is that?make blood! How cool is that?

Fun bone factsFun bone facts

The human hand has 27 The human hand has 27 bones, your face has 14bones, your face has 14

The longest bone in your body The longest bone in your body is your femur, ¼ your height.is your femur, ¼ your height.

Humans and Giraffes have the Humans and Giraffes have the same number of bones in their same number of bones in their necks.necks.

Check for learning IICheck for learning II

On your answer sheet, answer the On your answer sheet, answer the following questions. Do not refer to your following questions. Do not refer to your worksheet.worksheet.

3.3. How many different types of bone cells How many different types of bone cells are there?are there?

4.4. List three functions of your bones.List three functions of your bones.

5.5. How many bones does a newborn baby How many bones does a newborn baby have? How many bones do you have?have? How many bones do you have?