The (Human) Musculoskeletal System

THE SKELETAL SYSTEM

Composed of the body’s: 1. bones, and associated 2. ligaments 3. tendons 4. cartilages

BONES: An adult skeleton contains 206 bones. Do you know how many bones you were born with? You were born with 300 bones! As you grew some of these bones fused together.

Bone Structure BONES:

Types of Bone: 1. Long Bones:  much longer than they are wide  examples: - bones in your arms (humerus, radius, ulna) and legs (femur, tibia, fibula)

TYPES OF BONES: 2. Short Bones:  rough and cube shaped  examples: - bones in your wrists (carpals) and ankles (tarsals)

TYPES OF BONES: 3. Flat bones:  flat and usually a bit curved  examples: - skull and scapula

TYPES OF BONES: 4. Irregular Bones:  unusually shaped  don’t fit into the other 3 groups  examples: - vertebrae (butterfly-shaped) - sacrum & coccyx

The Skeletal System skull humerus femur ribs vertebrae sacrum

FUNCTIONS: 1. Support 2. Protection 3. Reservoir for minerals 4. Blood Cell Formation 5. Movement

1. Support: - the weight of the erect body (bones of the legs, pelvic girdle, and vertebral column) - teeth (mandible - jawbone) Note: Other bones support various organs and tissues.

2. Protection: - ribs & sternum protect the lungs and heart - skull protects the brain - vertebrae protect the spinal cord

3. Reservoir : - 99% of the body’scalcium is stored inbone. - 85% of the body’sphosphorous is storedin bone.

4. Blood Cell Formation Running along the center of your bones is a cavity filled with bone marrow. Bone Marrow: is a thick, spongy material inside your bones that makes red/white blood cells and platelets

5. Movement: - Skeletal muscles use the bones as levers to move the body.

HOW DO YOU MOVE?  Your muscles contract & pull on your bones to move them. Muscles work in pairs to move our body parts.

HOW DO YOU MOVE? 1. one muscle (flexor) bends the limb 2. the other muscle (extensor) straightens the limb back to the original position

The Muscular System  muscular system muscular system

The Muscular System:  You have over 600 muscles in your body.  They do anything from pumping your heart to moving your baby toe.  You have control of some of your muscles while others you have no control over (like your heart).

The Muscular System deltoid biceps abdominals quadriceps triceps hamstrings

Types of Muscle:

1. Cardiac Muscle:  Muscle that makes up your heart is called myocardium.  pumps blood around the body  you can’t control it

2. Smooth muscle  involuntary muscles (You don’t control these muscles- your brain and body tells these muscles what to do.)  allow blood vessels to dilate/constrict to increase/decrease blood flow to a particular area Types of Muscle:

SMOOTH MUSCLES CAN HELP…  found in your digestive tract to move your food along  pushes food back up your esophagus and out of your mouth when you are sick (throwing up)

3. Skeletal Muscle  used for locomotion - the physical movement of our body i.e. to walk/run, to lift things, to throw a ball, etc.  voluntary muscles (you decide to use them)  work with your bones to give your body power and strength Types of Muscle:

Do the following… 1.Raise your eyebrows. 2.Smile! 3.Frown! 4.Wiggle your tongue (not at anybody, please)! 5.Close your eyelids (but don't go to sleep, we still have work to do)!  You just used your skeletal muscles!

Classwork / Homework  Opposable Thumb Activity