MUSCULAR MUSCULAR SYSTEMSYSTEM

HST I

2010 - 2011

Structure and FunctionStructure and Function

The human body has more The human body has more than 600 muscles than 600 muscles

Characteristics of MusclesCharacteristics of Muscles

ExcitabilityExcitability ContractibilityContractibility ExtensibilityExtensibility ElasticityElasticity

ExcitabilityExcitability

Irritability, the ability to respond Irritability, the ability to respond to a stimulus such as a nerve to a stimulus such as a nerve impulseimpulse

ContractibilityContractibility

Muscle fibers that are stimulated Muscle fibers that are stimulated by nerves by nerves contractcontract, or become , or become short and thick, which causes short and thick, which causes movementmovement

ExtensibilityExtensibility

The ability to be stretchedThe ability to be stretched

ElasticityElasticity

Allows the Allows the muscle to muscle to return to its return to its original shape original shape after it has after it has contracted or contracted or stretchedstretched

Skeletal MuscleSkeletal Muscle

Makes up more than 40% of a Makes up more than 40% of a person’s body weightperson’s body weight

Looks striated, or banded, under the Looks striated, or banded, under the microscopemicroscope

Skeletal muscles have three parts Skeletal muscles have three parts Origin is one end of the muscle, Origin is one end of the muscle,

attached to the less movable part of attached to the less movable part of the bone the bone

Insertion is the other end of the Insertion is the other end of the muscle, attached to the more muscle, attached to the more movable part of the bone movable part of the bone

The action, or body, is the thickThe action, or body, is the thick middle part of the musclemiddle part of the muscle

Skeletal Muscles (cont.)Skeletal Muscles (cont.)

Skeletal muscles Skeletal muscles attach to bones in attach to bones in different waysdifferent ways Tendons-strong Tendons-strong

tough, fibrous tough, fibrous connective- tissue connective- tissue cordscords

Fascia- a tough Fascia- a tough sheetlike membrane sheetlike membrane that covers and that covers and protects the tissueprotects the tissue

Visceral Visceral MuscleMuscle

Lines various hollow organsLines various hollow organs Makes up the walls of blood Makes up the walls of blood

vesselsvessels Found in the tubes of the Found in the tubes of the

digestive systemdigestive system Smooth and has no striationsSmooth and has no striations Controlled by the autonomic Controlled by the autonomic

nervous system nervous system

Cardiac MuscleCardiac Muscle

Found only in the Found only in the heartheart

Striated muscle Striated muscle Under involuntary Under involuntary

controlcontrol Has specialized Has specialized

cells that provide cells that provide a stimulus for a stimulus for contractioncontraction

SternocleidomastoidSternocleidomastoid

Location: Side Location: Side of neckof neck

Function: Function: Turns and Turns and flexes headflexes head

TrapeziusTrapezius

Location: Location: Upper back Upper back and neckand neck

Function: Function: Extends head, Extends head, moves moves shouldershoulder

DeltoidDeltoid

Location: Location: ShoulderShoulder

Function: Function: Abducts arm, Abducts arm, injection siteinjection site

Biceps brachiiBiceps brachii

Location: Location: Upper armUpper arm

Function: Function: Flexes lower Flexes lower arm and arm and supinates handsupinates hand

Triceps brachiiTriceps brachii

Location: Location: Upper armUpper arm

Function: Function: Extends and Extends and adducts lower adducts lower armarm

Pectoralis majorPectoralis major

Location: Location: Upper chestUpper chest

Function: Function: Adducts and Adducts and flexes upper flexes upper armarm

IntercostalsIntercostals

Location: Location: Between ribsBetween ribs

Function: Function: Moves ribs for Moves ribs for breathingbreathing

Rectus abdominusRectus abdominus

Location: Location: Ribs to pubis Ribs to pubis (pelvis)(pelvis)

Function: Function: Compresses Compresses abdomen abdomen and flexes and flexes vertebral vertebral columncolumn

Latissimus dorsiLatissimus dorsi

Location: Location: Spine around Spine around to chestto chest

Function: Function: Extends and Extends and adducts adducts upper armupper arm

Gluteus maximusGluteus maximus

Location: Location: ButtocksButtocks

Function: Function: Extends and Extends and rotates thigh, rotates thigh, injection siteinjection site

SartoriusSartorius

Location: Front Location: Front of thighof thigh

Function: Function: Abducts thigh, Abducts thigh, flexes legflexes leg

Quadriceps femorisQuadriceps femoris

Location: Location: Front of thighFront of thigh

Function: Function: Extends leg, Extends leg, injection siteinjection site

Tibialis anteriorTibialis anterior

Location: Location: Front of lower Front of lower legleg

Function: Function: Flexes and Flexes and inverts footinverts foot

GastrocnemiusGastrocnemius

Location: Back Location: Back of lower legof lower leg

Function: Function: Flexes and Flexes and supinates sole supinates sole of the footof the foot

Basic Types of Muscle Basic Types of Muscle MovementMovement AdductionAdduction AbductionAbduction FlexionFlexion ExtensionExtension RotationRotation

AdductionAdduction

Moving a body Moving a body part toward the part toward the midlinemidline

AbductionAbduction

Moving a body Moving a body part away from part away from the midlinethe midline

FlexionFlexion

Decreasing the Decreasing the angle between angle between two bones, or two bones, or bending a body bending a body partpart

ExtensionExtension

Increasing the Increasing the angle between angle between two bones, or two bones, or straightening a straightening a body partbody part

RotationRotation

Turning a body Turning a body part around its part around its own axis; for own axis; for example, example, turning the head turning the head from side to from side to side.side.

CircumductionCircumduction

Moving in a circle Moving in a circle at a joint, or at a joint, or moving one end moving one end of a body part in a of a body part in a circle while the circle while the other end remains other end remains stationary, such stationary, such as swinging a arm as swinging a arm in a circlein a circle

Body MechanicsBody Mechanics

Body Mechanics is the way in Body Mechanics is the way in which the body moves and which the body moves and maintains balance while making maintains balance while making the most efficient use of all its the most efficient use of all its body parts.body parts. To prevent injury to yourself and To prevent injury to yourself and

others while working in the health others while working in the health field, it is important to observe field, it is important to observe good body mechanicsgood body mechanics

Four Main Reasons for Using Four Main Reasons for Using Good Body MechanicsGood Body Mechanics

Muscles work best when used Muscles work best when used correctly.correctly.

Correct use of muscles makes Correct use of muscles makes lifting, pulling and pushing lifting, pulling and pushing easiereasier

Prevents unnecessary fatigue, Prevents unnecessary fatigue, strain and saves energystrain and saves energy

Prevents injury to self and Prevents injury to self and othersothers

Eight Basic Rules of Good Eight Basic Rules of Good Body MechanicsBody Mechanics

1)Maintain a broad base of support by 1)Maintain a broad base of support by keeping the feet 8-10 inches apartkeeping the feet 8-10 inches apart

2)Bend from the hips and knees to get 2)Bend from the hips and knees to get close to an object, and keep your close to an object, and keep your back straightback straight

3)Use the strongest muscles to do the 3)Use the strongest muscles to do the job (shoulders, upper arms, hips and job (shoulders, upper arms, hips and thighs)thighs)

4)Use the weight of your body to help 4)Use the weight of your body to help push or pull an object. Whenever push or pull an object. Whenever possible, push, slide, or pull rather possible, push, slide, or pull rather than liftthan lift

Eight Basic Rules of Good Eight Basic Rules of Good Body MechanicsBody Mechanics

5)Carry heavy objects close to the 5)Carry heavy objects close to the bodybody

6)Avoid twisting your body as you 6)Avoid twisting your body as you work. Turn with your feet and entire work. Turn with your feet and entire body when you change direction of body when you change direction of movementmovement

7)Avoid bending for long periods7)Avoid bending for long periods

8)If a patient or object is too heavy for 8)If a patient or object is too heavy for you to lift alone, always get help you to lift alone, always get help

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