Skeletal System. Bones Protect. Bones. Bones Store. Bones Move SECTION 2: THE SKELETAL SYSTEM 4/4/16

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1 Skeletal System Skeletal system: the orga system whose primary fuctio is to support ad protect the body ad to allow the body to move SECTION 2: THE SKELETAL SYSTEM Boes The adult huma skeleto has 206 boes. Boes protect, store, move, ad make blood. Boes Protect Your heart ad lugs are protected by ribs, your spial cord is protected by vertebrae, ad your brai is protected by the skull Boes Store Boes store mierals that help your erves ad muscles fuctio properly. Log boes store fat that ca be used for eergy. Boes Move Skeletal muscles pull o boes to produce movemet. Without boes, you would ot be able to sit, stad, walk or ru. How Our Arm Moves Bioic Limbs 1

2 Boes Forms Blood Some of your boes are filled with a special material that makes blood cells. This material is called marrow. How Blood is Made Boe Structure Boe is made of coective tissue ad mierals. mierals are deposited by livig cells called osteoblasts Two Kids of Boe Tissue Boe Marrow Compact boe does ot have ay visible ope spaces rigid ad dese tiy caals withi compact boe cotai small blood vessels Spogy boe has may ope spaces provides most of the stregth ad support for a boe Marrow soft tissue cotaied i boes There are two types of marrow. 1. Red marrow produces both red ad white blood cells 2. Yellow marrow foud i the cetral cavity of log boes stores fat Boe Growth Figure 2 I childre, red marrow fills the ceter of log boes. This red marrow is replaced with yellow marrow as childre become adults. Most boes start out as a flexible tissue called cartilage. Whe you were bor, you did t have much true boe. But as you grew, most of the cartilage was replaced by boe. As a child, you had growth plates to allow your boes ad body to grow That cartilage turs to boe as you grow up 2

3 Joits Joit - a place where two or more boes meet allow your body to move whe your muscles cotract Some joits allow little to o movemet, these are called fixed joits Joits Joits are classified by how they move. Joits are held together by ligamets Ligamets are strog elastic bads of coective tissue Coect the boes i a joit Cartilage covers the eds of may boes Skeletal System Ijuries Boes ca be fractured or broke Joits ca be ijured dislocated joit - joit i which oe or more boes have bee moved out of place Sprai happes if a ligamet is stretched too far or tor Osteoporosis Osteoporosis a disease that causes boes to become less dese Become weak ad break easily More likely i people with bad eatig habits ad old age 3

4 Arthritis Arthritis a disease that affects the joits Paiful Swell ad stiffe More likely i older people Skeletal System Recap Crash Course o Skeletal System v=rw46rqkwa-g Muscular System Made up of the muscles that let you move SECTION 3: MUSCULAR SYSTEM 4

5 4/4/16 Kids of Muscle 1. Smooth Muscle 3 kids of muscle Locatio I digestive tract & blood vessel walls Smooth muscle Cardiac muscle Skeletal muscle Fuctio 2. Cardiac Muscle foud oly i the heart pumps blood aroud the body Muscle Actio Ca be volutary or ivolutary Volutary Uder your cotrol Examples: skeletal ca be both Locatio Fuctio 3. Skeletal Muscle Locatio Moves food through digestive system attached to boes for movemet Fuctio protect ier orgas eables boes to move Movemet Skeletal muscles make hudreds of movemets Whe you wat to move, sigals travel from your brai to your skeletal muscle Ivolutary Not uder your cotrol smooth ad cardiac muscle Ca blik your eyes but they also blik automatically Examples: 5

6 How Muscles Work Video Muscles Attach to Boes Tedos Strads of tough coective tissue that attach muscle to boes Whe muscle that coects two boes gets shorter, the boes are pulled closer to each other Muscles Work i Pairs Usually, oe muscle beds part of the body The other muscle straightes part of the body Flexor & Extesor Flexor Muscle that beds part of your body Example: biceps Extesor Muscle that straightes part of your body Example: triceps Use it or Lose it Whe someoe wears a cast it weakes the muscle aroud the boe Exercised muscles are stroger ad larger Strog muscles are good for your body Squeeze blood vessels to icrease blood flow 6

7 Resistace Exercises Stregthes skeletal muscles Work agaist resistace, or weight, of a object Examples: curlups, liftig Aerobic Exercise Steady, moderate activity Examples: joggig, cyclig, skatig, swimmig Ca icrease muscle stregth but mostly stregthes heart ad icreases edurace Muscle Ijury Start exercise programs slowly & warm up Less likely to get hurt Strais Tediitis Strais Strai ijury i which a muscle or tedo is overstretched or tor Happe whe muscle is overworked or ot warmed up Tediitis Exercise too much Muscles get iflamed Need log rest to fix it Aabolic Steroids Drugs that make muscles stroger Cause log-term health problems Damage heart, liver, ad kideys Ca also cause high blood pressure If take before skeleto is mature, ca stop boe growth. 45 Miute Documetary: 7