Muscular System

Muscular System

Functions of the Muscular SystemAllows movementMaintains postureStabilizes jointsGives the body shapeGenerates heat

2 Categories of MusclesVoluntary MusclesInvoluntary MusclesMuscles you can controlExamples: muscles in your arms and legsMuscles you cannot controlExamples: heart, stomach, diaphragm

3 Types of Muscle: SkeletalSkeletal: muscles that move bonesStriated (striped)VoluntaryTires easilyFound in bundles

3 Types of Muscle: SmoothSmooth: muscles that control internal organsNo striationsInvoluntaryMakes up internal organs (stomach, intestines)Does not tire

3 Types of Muscle: CardiacCardiac: muscle that makes up the heartStriated (striped)InvoluntaryDoes not tire

RememberWhat are ligaments?Strong bands of tissue that connect bones to each other at a joint

TendonsStrong bands of tissue that attach a muscle to a bone

Muscular InjuriesSprain: ligaments stretched or tornStrain: muscles stretched or tornCramp: a muscle involuntarily contracted that will not relax

Fun Fact!Sartorius: longest muscle in the human body

How skeletal muscles workMuscles only contractThey pull, they dont pushSkeletal muscles work in pairsExample in the arm:When the biceps contracts, the triceps relaxesWhen the triceps contracts, the biceps relaxes

EnergyMuscles use energy to moveWhen muscles run out of energy = muscle fatigueWhen true fatigue hits, a muscle cannot be contracted even when stimulatedhttps://youtu.be/LKhkvSRQZYo

2 Types of ExerciseAerobic Exercise (air exercise)Jogging, biking, swimmingMakes muscles stronger, more flexible, and more resistant to fatigueIncreases metabolismEnlarges heartLungs become more efficientDOES NOT increase muscle mass much

2 Types of ExerciseAnaerobic Exercise (no air exercise)WeightliftingIncreases muscle massDoes not increase endurance

Muscle BasicsMyofibril: a muscle cellSarcomere: a tiny contractile unit of a muscleA myofibril is made of many, many sarcomeres

Muscle BasicsOne sarcomere is made of interlocking actin and myosin