GCSE Physical GCSE Physical EducationEducation

The Muscular SystemThe Muscular System

PectoralsDeltoids

Biceps

Abdominals

Quadriceps Hamstrings

Latissimus Dorsi

Trapezius

Triceps

Gastrocnemius

Gluteals

Front View Back View

The Muscular SystemThe Muscular SystemThese are the major muscles of the body…These are the major muscles of the body…

Functions of the Body MusclesFunctions of the Body Muscles

MuscleMuscle Position in the Position in the bodybody

Main ActionMain Action

Gluteals In the middle of the In the middle of the body at the back, body at the back, forming the forming the bottom.bottom.

At the top of each At the top of each leg at the back.leg at the back.

At the bottom of At the bottom of each leg at the each leg at the back. Also known as back. Also known as the calf muscles.the calf muscles.

Pull or extends Pull or extends the legs back at the legs back at the hips.the hips.

Bend or flexes Bend or flexes the legs at the the legs at the knees.knees.

Straighten the Straighten the foot so you can foot so you can stand on your stand on your toes.toes.

Hamstrings

Gastrocnemius

MuscleMuscle Position in the Position in the BodyBody

Main ActionMain Action

Latissimus

Dorsi

Triceps

At the back of At the back of the body, either the body, either side of the chest.side of the chest.

At the top of At the top of each arm at the each arm at the back.back.

Extension and Extension and adduction of the adduction of the shoulders and shoulders and back behind back behind your back.your back.

extension the extension the arms at the arms at the elbow.elbow.

Trapezius

In the centre of In the centre of the chest at the the chest at the back of the body, back of the body, spreading up.spreading up.

Hold and rotate Hold and rotate the shoulders the shoulders and also move and also move the head back the head back and sideways.and sideways.

MuscleMuscle Position in Position in the Bodythe Body

Main ActionMain Action

Deltoids

Biceps

Quadriceps

In the upper In the upper part of the part of the body, covering body, covering the shoulders.the shoulders.

At the top of At the top of each arm at each arm at the front.the front.

At the top of At the top of each leg at each leg at the front.the front.

Raise the arms Raise the arms in all directions in all directions at the at the shoulders. shoulders. AbductionAbduction

Flex the arms Flex the arms at the elbows.at the elbows.

Extension the Extension the legs at the legs at the knees.knees.

MuscleMuscle Position in the Position in the bodybody

Main ActionMain Action

Pectorals In the upper In the upper part of the part of the chest at the chest at the front.front.

At the front of At the front of the body in the the body in the middle, just middle, just below the chest.below the chest.

Raise the arms Raise the arms up, sideways and up, sideways and across the chest across the chest at the shoulders.at the shoulders.

Pull in the Pull in the abdomen and abdomen and flex the spine so flex the spine so you can bend you can bend forward.forward.

Abdominals

MusclesMuscles There are 3 types of muscles There are 3 types of muscles

within the muscular system:within the muscular system:Voluntary (skeletal)Voluntary (skeletal) InvoluntaryInvoluntaryCardiac Cardiac

Antagonistic pairsAntagonistic pairs As muscles can only pull, not push, they are As muscles can only pull, not push, they are

usually arranged in usually arranged in antagonistic pairsantagonistic pairs One muscle will bend (flex) the joint and the One muscle will bend (flex) the joint and the

other will straighten (extend) the joint.other will straighten (extend) the joint. Whilst one muscle contracts (agonist), the Whilst one muscle contracts (agonist), the

other relaxes (antagonist). Allowing full other relaxes (antagonist). Allowing full movement at the joint.movement at the joint. E.g. the bicep contracts to flex the elbow whilst E.g. the bicep contracts to flex the elbow whilst

the tricep relaxes.the tricep relaxes. This is known as an This is known as an isotonic contractionisotonic contraction If both muscles contract together then no If both muscles contract together then no

movement takes place. This is known as an movement takes place. This is known as an isometric contraction.isometric contraction.

EFFECTS OF EXERCISE EFFECTS OF EXERCISE TASK…TASK…

WHAT ARE THE EFFECTS OF WHAT ARE THE EFFECTS OF EXERCISE?EXERCISE?

INCLUDE:INCLUDE: FIBRES LENGTHEN AND SHORTENFIBRES LENGTHEN AND SHORTEN EXTRA WASTE PRODUCTS CREATEDEXTRA WASTE PRODUCTS CREATED EXTRA BLOODEXTRA BLOOD ANAEROBIC AND AEROBICANAEROBIC AND AEROBIC LACTIC ACIDLACTIC ACID CRAMPCRAMP

HOW DO MUSCLES WORK?HOW DO MUSCLES WORK? DRAW UP A TABLE TO GIVE AND DRAW UP A TABLE TO GIVE AND

EXPAIN EXAMPLES OF EACHEXPAIN EXAMPLES OF EACH

1. Isotonic Contraction

Force

The muscle changes length as it works; either lengthening or shortening.

Shortening is called a concentric contraction. Give examples Lengthening is called an eccentric contraction. (Acts as a break) The hamstrings and quadriceps in the legs work in this way when performing squats.

The 'biceps curl' is a good example of isotonic contraction.

Lengthening

Eccentric Contraction

Shortening

Concentric contraction

2. Isometric Contraction

The hand push is another good example of isometric contraction. NAME SPORTS THAT REQUIRE ISOMETRIC CONTRACTION

ForceForce

There is no movement!

As a result there is no movement.

The muscle stays the same length as it works.

The muscles in the back are a good example - the trapezius works in this way when maintaining our posture.

.

Antagonistic pairsAntagonistic pairs

Muscle ToneMuscle Tone Muscle cells are never all resting at the same Muscle cells are never all resting at the same

time.time. Some are muscles are always ready for action – Some are muscles are always ready for action –

this is known as this is known as muscle tone.muscle tone. One of the functions of muscle tone is that it One of the functions of muscle tone is that it

keeps the body primed and ready for instant keeps the body primed and ready for instant action.action. Also keeps the body in an upright positionAlso keeps the body in an upright position

This is called This is called POSTUREPOSTURE

Our joints are held firm by the flexor and Our joints are held firm by the flexor and extensor muscles both working at the same timeextensor muscles both working at the same time

HomeworkHomework

EXPAIN IN DETAIL WHAT IS EXPAIN IN DETAIL WHAT IS MEANT BY:MEANT BY:

HYPERTROPHYHYPERTROPHY ATROPHYATROPHY