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

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 Stores certain materials until your body needs them like calcium.

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

Body systems that work with the skeletal system; The skeletal system needs blood flow and produced red blood cells for the circulatory system, needs minerals from the digestive system and requires the muscular system for movement

Which cell part is like the skeletal system? microtubules

The Muscular System

There are approximately 600 muscles in your bodyThere are approximately 600 muscles in your body

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

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

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

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

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

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

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

Body systems that work with the muscular system; The muscles need food from the digestive system and oxygen from the respiratory system delivered by the circulatory system. They also depend on the circulatory and excretory system to remove waste products and the skeletal system to allow movement