The Muscular System. How many muscles do you have in the body? Approximately 640 muscles! Muscles...
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Transcript of The Muscular System. How many muscles do you have in the body? Approximately 640 muscles! Muscles...
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 MaximusGluteus Maximus Location:Location: Buttocks
Function:Function: Straightens hip
Notes: Notes: Sitting to standing
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