The Muscular SystemThe Muscular System

Key ConceptsKey Concepts

1.1. What types of muscles are What types of muscles are found in the body?found in the body?

2.2. Why do skeletal muscles Why do skeletal muscles work in pairs?work in pairs?

Key TermsKey Terms

Involuntary muscleInvoluntary muscle

Voluntary muscleVoluntary muscle

Skeletal muscleSkeletal muscle

TendonTendon

Striated muscleStriated muscle

Smooth muscleSmooth muscle

Cardiac muscleCardiac muscle

There are about 600 muscles in the human body

Types of MusclesTypes of Muscles

Involuntary Muscles – Muscles that are not Involuntary Muscles – Muscles that are not under your conscious control – involved in under your conscious control – involved in breathing and digesting foodbreathing and digesting food

Voluntary Muscles – Muscles that are under Voluntary Muscles – Muscles that are under your conscious control – smiling, turning a your conscious control – smiling, turning a page, getting out of a chairpage, getting out of a chair

Three types of muscle tissue:Three types of muscle tissue:– Skeletal, smooth and cardiacSkeletal, smooth and cardiac

Skeletal muscleSkeletal muscleAttaches to and moves Attaches to and moves bones bones – Looks striated or banded Looks striated or banded

under a microscopeunder a microscope– Move only when you want Move only when you want

them to: voluntary them to: voluntary – React quickly and tire React quickly and tire

quicklyquickly

Tendon – strong Tendon – strong connective tissue that connective tissue that attaches muscle to boneattaches muscle to bone

Smooth MuscleSmooth Muscle

Smooth – found on the inside of many Smooth – found on the inside of many internal organs – Ex. Stomachinternal organs – Ex. Stomach

InvoluntaryInvoluntary– Help to control breathing, blood pressure, Help to control breathing, blood pressure,

and movements of the digestive systemand movements of the digestive system

No striations or bandsNo striations or bands

React slowly, tire slowlyReact slowly, tire slowly

Cardiac MuscleCardiac Muscle

Found only in the heartFound only in the heart

Some characteristics of both skeletal and Some characteristics of both skeletal and smoothsmooth

InvoluntaryInvoluntary

StriatedStriated

Does not tireDoes not tire

Contracts repeatedly Contracts repeatedly – heart beatheart beat

Muscles at WorkMuscles at Work

Skeletal muscles only contract when they Skeletal muscles only contract when they receive a message from nervous system.receive a message from nervous system.

Muscles do work only by contracting or Muscles do work only by contracting or shortening.shortening.

For movements need 2 muscles or groups For movements need 2 muscles or groups of muscles (always work in pairs)of muscles (always work in pairs)

Ex. Biceps and triceps work together to Ex. Biceps and triceps work together to bend and straighten your arm.bend and straighten your arm.

Muscular Strength and FlexibilityMuscular Strength and Flexibility

Exercise makes individual muscle cells Exercise makes individual muscle cells grow in size – that makes the whole grow in size – that makes the whole muscle thickermuscle thicker

The thicker the muscle the stronger it isThe thicker the muscle the stronger it is

Stretching makes muscles more flexibleStretching makes muscles more flexible

Prepares muscles for exercise or playPrepares muscles for exercise or play

Muscle InjuriesMuscle Injuries

Muscle strain or pulled muscle – when Muscle strain or pulled muscle – when muscles are overworked or overstretchedmuscles are overworked or overstretched

Tendons can also be overstretched or Tendons can also be overstretched or partially tornpartially torn

Muscle cramp – whole muscle contracts Muscle cramp – whole muscle contracts strongly and stays contractedstrongly and stays contracted