The The Muscular Muscular SystemSystem

How many muscles do you How many muscles do you have in the body?have in the body?

Approximately Approximately 640 640 muscles!muscles!

Muscles make upMuscles make upapproximately 40% of yourapproximately 40% of yourbody weightbody weight

Types of MusclesTypes of Muscles

Voluntary muscles Voluntary muscles – muscles you can – muscles you can control by will or thinkingcontrol by will or thinking

What is an example?What is an example?

Involuntary muscles Involuntary muscles – muscles you cannot– muscles you cannot

control at will, but work automaticallycontrol at will, but work automatically

What is an example?What is an example?

Different Kinds of MusclesDifferent Kinds of Muscles

1.1. Skeletal muscle (voluntary) Skeletal muscle (voluntary) 2.2. Smooth (involuntary) Smooth (involuntary) 3.3. Cardiac (involuntary)Cardiac (involuntary)

Skeletal Skeletal

StriatedStriated muscles muscles Holds the skeleton togetherHolds the skeleton together Gives the body shapeGives the body shape Helps with everyday movementsHelps with everyday movements

Smooth Smooth Controlled by nervous system automaticallyControlled by nervous system automatically Examples of smooth muscles are the walls Examples of smooth muscles are the walls

of the stomach and intestines, which help of the stomach and intestines, which help break up food and move it through the break up food and move it through the digestive system.digestive system.

Smooth muscle is also found in the walls of Smooth muscle is also found in the walls of blood vessels, where it squeezes the stream blood vessels, where it squeezes the stream of blood flowing through the vessels to help of blood flowing through the vessels to help maintain blood pressuremaintain blood pressure

CardiacCardiac

Found in the heartFound in the heartThe walls of the heart's chambers The walls of the heart's chambers

are composed almost entirely of are composed almost entirely of muscle fibers.muscle fibers.

Its rhythmic, powerful contractions Its rhythmic, powerful contractions force blood out of the heart as it force blood out of the heart as it beats.beats.

How does movement occur?How does movement occur?

The The motor cortexmotor cortex sends an electrical sends an electrical signal through the spinal cord and signal through the spinal cord and peripheral nerves to the muscles, causing peripheral nerves to the muscles, causing them to contract them to contract

The motor cortex on the The motor cortex on the rightright side of the side of the brain controls the muscles on the brain controls the muscles on the left left side side of the body and vice versa of the body and vice versa

The The cerebellumcerebellum coordinates the muscle coordinates the muscle movements ordered by the motor cortex movements ordered by the motor cortex

Movement continuedMovement continued

SensorsSensors in the muscles and joints send in the muscles and joints send messages back through peripheral nerves to tell messages back through peripheral nerves to tell the cerebellum and other parts of the brain where the cerebellum and other parts of the brain where and how the arm or leg is moving and what and how the arm or leg is moving and what position it's in position it's in

Muscles move body parts by Muscles move body parts by contractingcontracting and then and then relaxingrelaxing. Your muscles can pull bones, but they . Your muscles can pull bones, but they can't push them back to their original position.can't push them back to their original position.

They work in pairs of They work in pairs of flexorsflexors and and extensorsextensors

What is the longest What is the longest muscle?muscle?

SartoriusSartorius

(Quadricep muscle)(Quadricep muscle)

What is the smallest What is the smallest muscle?muscle?StapediusStapedius

(Inside the ear)(Inside the ear)

What is the widest What is the widest muscle?muscle?

External obliqueExternal oblique

(Runs around the side of (Runs around the side of the upper body)the upper body)

What is the biggest What is the biggest muscle?muscle?

Gluteus maximusGluteus maximus

(In your buttock)(In your buttock)

SternocleidomastoidSternocleidomastoid

Location:Location: Side of the neck

Function:Function: Pulls head back and rotates head

Pectoralis MajorPectoralis MajorLocation:Location:

Chest

Function:Function: Brings arms toward chest

TrapeziusTrapezius Location:Location: Upper

back and neck

Function:Function: Moves shoulders up and down

Notes:Notes: Shrugs shoulders

DeltoidDeltoid Location:Location:

Surrounds the shoulder joint

Function:Function: Lifts arm away from body

BicepsBiceps Location:Location: Front

of the upper arm

Function:Function: Pulls lower arm up (flexion)

TricepsTriceps Location:Location: Back of

upper arm

Function:Function: Pulls lower arm down (extension)

Notes:Notes: extends arm back

Latissimus DorsiLatissimus Dorsi Location:Location: Down

the spine and across the back

Function:Function: Pulls arm toward the back

External ObliqueExternal Oblique Location:Location: Outside

part of trunk

Function:Function: Trunk rotation

Rectus AbdominusRectus Abdominus Location:Location:

Center of stomach

Function:Function: Stabilize the trunk area

Gluteus MediusGluteus MediusLocation:Location: Hip

area

Function:Function: Lift leg out to the side

Gluteus MaximusGluteus Maximus Location:Location: Buttocks

Function:Function: Straightens hip

Notes: Notes: Sitting to standing

SartoriusSartorius Location:Location: Inner side of

upper thigh

Function:Function: Pulls leg inward

Rectus FemorisRectus Femoris Location:Location: Front

center thigh

Function:Function: Straightens knee and bends hip

Vastus LateralisVastus Lateralis Location:Location: Front

outside part of thigh

Function:Function: Straightens knee

Vastus MedialisVastus Medialis Location:Location: Front inner

part of thigh

Function:Function: Straightens knee

Biceps FemorisBiceps FemorisLocation:Location: Back

outside thigh

Function:Function: Bends knee and straightens hip

SemitendonosusSemitendonosusLocation:Location: Back inside

thigh

Function:Function: Bends knee and straightens hip

GastrocnemiusGastrocnemius Location:Location: Outside lower

back of leg

Function:Function: Raises heel

SoleusSoleusLocation:Location: Inside back

of lower leg

Function:Function: Raises heel

Tibialis AnteriorTibialis AnteriorLocation:Location: Front of

lower leg

Function:Function: Pulls toes up