2 The muscular system is made up of… MusclesandTendons
3 Functions of Muscles Hold your organs in place Hold your bones together so that you can moveHelp you chew your foodOpen and close your eyelidsPump your bloodAllow you to run and playHelp you to smile
4 Muscle Action Involuntary muscles •impossible to control completely •not under your conscious control•responsible for activities such as:-breathing-digesting foodVoluntary muscles•muscles that are under your control•actions controlled by voluntary muscles:-smiling-turning a page in a book-getting out of your chair when the bell rings
5 Types of MusclesCardiac muscleSkeletal muscleSmooth muscle
6 Skeletal Muscle Functions Attached to the bones of your skeletonProvide the force that moves your bonesAt each end of a skeletal muscle is a tendonTendon: a strong connective tissue that attaches muscle to boneSkeletal muscle cells appear banded, or striated—sometimes called striated muscle
7 Skeletal Muscle Characteristics Classified as voluntary musclesReact very quickly- example: swimmer at a swim meet, leg muscles quickly push the swimmer off the block into the pool• Skeletal muscles tire quickly-example: by the end of the swim race, the swimmer’s muscles are tired and need a rest
8 Smooth Muscle Functions Involuntary musclesFound in the inside of many internal organs (walls of stomach and blood vessels)Work automatically to control many types of movements inside your body (digestion)Example:-as the smooth muscles of your stomach contract, they produce a churning action, the churning mixes the food with chemicals produced by your stomach. This action and these chemicals help to digest the food
9 Smooth Muscle Characteristics Smooth muscle cells are not striatedBehave differently than skeletal musclesReact more slowly and tire more slowly
10 Cardiac MuscleFunction -has characteristics in common with both smooth and skeletal muscles -involuntaryCharacteristics -muscle cells are striated -cardiac muscle does not get tired -can contract repeatedly (repeated contractions heartbeats) -found only in the heart
11 Muscles at WorkMuscles do their work by contracting, or becoming shorter and thickerContract when they receive messages from the nervous systemBecause muscle cells can only contract, not extend, skeletal muscles must work in pairs. While one muscle contracts, the other muscle in the pair returns to its original length.
12 Taking Care of Your Skeletal Muscles Exercise- maintain muscular strength and flexibilityMakes individual muscle cells grow wider—causes whole muscle to become thickerThe thicker a muscle is, the stronger the muscle isFlexibility- helps prepare your muscles for the work involved in exercising or playingUse precautions to help prevent muscle injuriesWarming upUsing proper safety equipment
13 Injured MusclesMuscle strain/pulled muscle– can occur when muscles are overworked or overstretchedTendons- may be overstretched or partially tornToo much exercise can lead to a skeletal muscle crampWhen muscles cramp, the entire muscle contracts strongly and stays contractedAlways follow medical instructions and rest your injured muscle or tendon until it heals
14 Fun FactsYou have over 30 facial muscles which create looks like surprise, happiness, sadness, and frowning.Eye muscles are the busiest muscles in the body. Scientists estimate they may move more than 100,000 times a day!The largest muscle in the body is the gluteus maximus muscle in the buttocks.There are about 60 muscles in the face. Smiling is easier than frowning. It takes 20 muscles to smile and over 40 to frown.