Procedure Flex your right arm and wrap your left hand around your bicep and triceps muscles.

Procedure Bend and straighten your arm several times and feel the two main muscles working under your skin.

Procedure Working in pairs, help each other to measure your bicep length while it is relaxed (straightened). Record your measurement in the chart. Use centimeters.

Procedure Working in pairs, help each other to measure your bicep length while it is contracted (flexed). Record your measurement in the chart. Use centimeters.

Procedure Working in pairs, help each other to measure your triceps length while it is relaxed (bent). Record your measurement in the chart. Use centimeters.

Procedure Working in pairs, help each other to measure your triceps length while it is contracted (straight). Record your measurement in the chart. Use centimeters.

Procedure Now measure the circumference of your upper arm while bent and straight. Record your numbers.

Types of muscle tissue Sketch the three types of muscle tissue in your spiral.

How did the biceps and triceps change as you bent and straightened your arm? When the arm was extended, the biceps would relax (lengthen) and the triceps would contract (shorten). The reverse happen when the arm is bent.

How do the skeletal muscles cause bones to move? Muscles are attached to bones by tendons. The muscles work in pairs and pull against the bone to cause movement.

What did your finding about the thickness of the upper arm suggest about how muscles work? The thickness of the arm stayed the same. Muscles must work in pairs. While one contracts, the opposing muscle must relax.

The Skeletal System

Is made up of: –bones –cartilage –tendons –ligaments –joints

The Skeletal System –Each bone in your body is a living organ, made of different tissues. Cells in bones take in food and use energy.

Number of Bones Infant or baby –305 bones Adult –206 bones –Bones in the skull, pelvis, spine, and long bones fuse

Skeleton Formation As a fetus, your skeleton starts out as cartilage –Connective tissue that is stronger than bone As you grow, the cartilage is replaced by bone Your ears and nose tip remain cartilage

Functions of the Skeletal System Provides shape and support Enables you to move Protects your internal organs Produces blood cells in the red marrow Stores calcium and phosphorous until your body needs them.

Bone Characteristics Bone is alive –Full of blood vessels –Contains nerves (pain if broken) Bone is made mainly of 2 minerals –Calcium –Phosphorous Bone grows and changes all the time

Spongy Bone Compact Bone Periosteum Bone Marrow Growth Plate

Bone Marrow Bone marrow is located in the hollow cavity inside of some bones –Red Produces blood cells –Yellow Fat and energy reserve

Joints of the Body

Joints Any place where two or more bones meet Ligaments: tough bands of tissue that hold bones together at the joints.

Body systems that work with the skeletal system; circulatory system transports blood to and from the bones digestive system provides minerals and vitamins muscular system moves the bones and joints

Which cell part is like the skeletal system? microtubules

The Muscular System

Muscles are the motors that move body partsMuscles are the motors that move body parts Bones and joints cannot move on their ownBones and joints cannot move on their own There are approximately 600 muscles in your bodyThere are approximately 600 muscles in your body 35 – 40% of body mass is muscle35 – 40% of body mass is muscle

Parts of the Muscular System skeletal muscleskeletal muscle smooth musclesmooth muscle cardiac musclecardiac muscle

Voluntary Muscles muscles under conscious controlmuscles under conscious control –smiling, walking, running, typing etc…

Skeletal Muscle muscles attached to bonesmuscles attached to bones voluntaryvoluntary striated (striped)striated (striped) muscle that reacts quickly and tires quicklymuscle that reacts quickly and tires quickly

Skeletal Muscle

Muscles at Work Skeletal muscle movements are results of pairs of muscles working together. –One muscle contracts while the other muscle relaxes. –Muscles always pull; they never push.

Muscles at Work Results of Muscle Action –Muscles contract This produces thermal energy, and it uses chemical energy. Thermal energy produces heat that helps keep body temperature constant. Chemical energy is from glucose. (When glucose is used up, muscles are tired and need to rest.)

Muscles at Work Results of Muscle action (cont.) –Over time, muscles become larger or smaller, depending on how much work they do.

Involuntary Muscles muscles not under conscious controlmuscles not under conscious control –You don’t have to think about them breathing, digesting, sneezing, heart beatingbreathing, digesting, sneezing, heart beating

Smooth Muscle found inside most blood vessels and organsfound inside most blood vessels and organs involuntaryinvoluntary not striated (striped)not striated (striped) reacts slowly and tires slowlyreacts slowly and tires slowly

Smooth Muscle

Cardiac Muscle found only in the heartfound only in the heart involuntaryinvoluntary striated (striped)striated (striped) does not get tireddoes not get tired

Cardiac Muscle

Tendons and ligaments help to attach muscles to the skeletal system so that they can work together.

Tendon Strong connective tissue that attaches muscle to bone

Ligament Bands of connective tissue connecting one bone to another bone

Functions of the Muscular System Allows the body to move Aids in circulation, respiration and digestion (circulatory and digestive system)

Body systems that work with the muscular system; digestive system provides energy respiratory system provides oxygen circulatory systems delivers oxygen and carries away waste excretory system also carries away waste skeletal system provides a frame