V. SKELETON

A. Skeleton Functions1. Provides support and shape

a. Internal framework b. determines body’s shape c. .

2. Protects your organs (Axial Skeleton)

a. Skull - the brainb. Rib cage - the heart and lungsc. Vertebrae - the spinal cord

3. Enables movement (Appendicular Skeleton)

a. Sites for muscle attachmentb. Pull of muscles makes movement

possible

4. Produces blood cells a. In the red bone marrow

5. Stores fat and mineralsa. Fat stored in yellow marrowb. Calcium and phosphate stored in a rigid

matrix

B. Skeleton Structure

1. Bonesa. 206 bonesb. Living tissue with blood vessels and nervesc. Endoskeleton (inside the body)d. .

2. Ligamentsa. Tough, flexible connective tissue b. Holds bones togetherc. Allows or prevents movement d. .

3. Cartilagea. Strong, flexible, smooth connective tissueb. Cushions ends of bonesc. Allows smooth movementd. .

C. Bone composition1. Compact bone tissue

a. Dense b. Rigid and hardc. Forms around blood capillaries that

feed the boned. .

2. Spongy bone tissuea. Lacy open spacesb. Provides strength and supportc. Found in long bones (arms and

legs)d. Sometimes contains red marrow

3. Mineral cycle – Growth and repaira. Osteoblasts (bone cells) build calcium and other

minerals into a matrix of bone1) process is called ossification

b. Osteoclasts (bone cells) break down bone and deposit the calcium back into the blood (to build new bone)

4. Connective tissuea. Collagen (a protein) makes bones flexible and

durable b. is woven into the matrix with the minerals

5. Marrowa. Soft tissue inside of bones

1) Red Marrowa) Produce red and white blood cells

2) Yellow Marrowa) Stores fat

D. Bone Growth

1. Fetus – most bones start as cartilage2. Cartilage replaced by bone as baby

grows3. Osteocytes (bone cells) move into

cartilage and change it into bone4. Cartilage in growth plates continues to

produce bone as child grows1. Directed by hormones

5. Growth finished at age 25-30 1. Hardens completely2. Can repair self if broken

E. Bone Connection - Joints

1. Jointsa. Allow movement or restrict

movementb. Connected by ligamentsc. Cushioned by cartilaged. Fuse in skull (as a baby grows)

2. Types of jointsa. Ball and socket

1) Allows rotation2) Example: shoulders and hips

3. Gliding jointsa. Allows flexibility in many directionsb. Example: Wrist and ankles

4. Hinge jointsa. Allows back and forth movement (like

door hinge)b. Example: knees and elbows

5. Pivot jointsa. Bones rotate and move slightly up and

downb. Example: vertebrae

Broken Wrist

F. Injuries and Disorders

1. Fracturesa. Impact breaks boneb. Usually heals in 6-8 weeks

2. Sprainsa. Injury to ligament – stretching joint too

far1) Tissues tear2) Swollen and painful to move3) Common sports injury

1. Osteoporosisa. Disease that causes bone tissue to

become thin and weakb. Weak bones break easilyc. Older adults who did not get enough

calcium before they were 30

2. Arthritisa. Disease causes joints to swell, stiffen

and become painful and misshapenb. Treated with drugs that reduce swelling

VI. Muscles

A. Function of Muscles1. Pump blood through body2. Stability and movement3. Move material inside the body

a. Blood in arteries and veinsb. Digestion system

1. Three types of musclesa. Skeletal

a. Voluntary – able to control movementsb. Contractions pull bones togetherc. Most work in pairs around a joint - one

contracts, the other relaxes1) Flexor bends a joint2) Extender straightens a joint3) Example: bicep (flexor) and tricep

(extender)

B. Three Types of Muscles

1. Smooth Musclea. Involuntary – not able to controlb. Internal organs and blood vesselsc. Moves materials through the body

1) Arteries and veins (blood)2) Digestive system (food and waste)

2. Cardiac Musclea. Tissue that makes up the heartb. Never gets tired – contains lots of

mitochondriac. Contractions push blood out of the heart

C. Injuries and disorders 1. Muscle strains and tears

a. Injury if overstretched or tornb. Occurs if muscles are not warmed or

stretched properly1) Muscle tissue swells and is painful2) Needs rest to heal

2. Muscular dystrophy1. Hereditary disease that causes skeletal

muscle to become weaker over time2. Affects how muscle proteins form3. Poor balance and difficulty walking

3. Tendinitisa. Inflammation of tendons that connect

muscle to bone b. Can be torn if overused c. Needs rest to heald. May be treated with medicines that

reduce inflammation

D. Benefits of Exercise

1. Increase strength, endurance and flexibility

2. Keeps heart, lungs and bones healthy

3. Reduces stress and helps with sleep