MUSCLES Muscles Structure Function DID YOU KNOW…A smile uses 17 muscles, a frown uses 43?

Muscle Categories  The skeleton cannot stand alone. Bones need to be held in place and moved by their own support system – the muscles.  Muscles are contractile tissue which are responsible for movement in the body from the slightest wink to the sustained effort needed to run a marathon

 Muscles make up from 35-40% of the body’s total weight  Did you know that: there are more 600 muscles in your body!!

Muscles are either:  Voluntary Voluntary muscles that you can move whenever you want to  Involuntary Muscles contract and relax automatically inside your body. We can not control them e.g. your stomach, digestive system (move food in and through), uterus, bladder, heart.

Types of Muscles  Smooth (involuntary)  Cardiac (involuntary)  Skeletal (voluntary)

Parts of a skeletal muscle  Muscle Origin Where muscles attach to a bone  Muscle Head The beginning of the muscle belly at the origin  Muscle Belly The fleshy part of the muscle  Muscle Insertion Where the muscle belly forms into a tendon to attach onto another bone

Did you know… Smallest Muscle  Is the stapedius  Length = 1/20th of an inch.  It is the activator of the stirrup that sends vibrations from the eardrum to the inner ear. Largest Muscle  is the latissimus dorsi Fastest Muscle  The eye muscle  It contracts in less than 1/100th of a second.

Muscles work in pairs  When one muscle is working the other is relaxed. We use the following terms to explain what each muscle is doing:  Agonist = is the working muscle  Antagonist = is the oppostie muscle which is not working (ie relaxed)

Agonist = biceps Antagonist = triceps Agonist = triceps Antagonist = biceps biceps triceps

MUSCLES – Turn to page 102 MuscleMain Action DeltoidShoulder abduction, flexion and extension PectoralsShoulder adduction and flexion Latissimus DorsiShoulder adduction and extension

TricepsElbow extension BicepsElbow Flexion AbdominalsTrunk Flexion and rotation Gluteus Maximus Hip abduction and extension HamstringsKnee flexion, hip extension

QuadricepsKnee extension, hip flexion Wrist FlexorsWrist Flexion Wrist ExtensorsWrist Extension GastrocnemiusPlantarflexion Tibialis AnteriorDorsiflexion

YOUR TURN…..  On page 102  Try to fill out the next table using the information you just collected.

MovementAgonistAntagonist Elbow FlexionBicepTricep Shoulder Abduction DeltoidPectorals + Latissimus Dorsi Elbow Extension TricepBicep

Knee FlexionHamstringQuadricep Shoulder Adduction Pectorals +Latissimus Dorsi Deltiod Knee Extension QuadricepsHamstrings Shoulder Flexion Deltoid + Pectorals Latissimus Dorsi

Hip ExtensionGluteus Maximus Hip Flexors Hip FlexionHip FlexorsGluteus Maximus PlantarflexionGastrocnemiusTibialis Anterior Wrist Extension Wrist Extensors Wrist Flexors

DorsiflexionTibialis Anterior Gastrocnemi us Shoulder extension Latissimus Dorsi Posterior Delt. Pectorals Anterior Delt Trunk flexionRectus Abdominus Erector Spinae Trunk extension Erector SpinaeRectus Abdominus