Chapter 10 Chapter 10

Muscular SystemMuscular System

Three types of musclesThree types of muscles

1) smooth muscles- involuntary muscles 1) smooth muscles- involuntary muscles example: large and small intestinesexample: large and small intestines

2) Cardiac muscles- involuntary muscle 2) Cardiac muscles- involuntary muscle example: heartexample: heart

3) 3) Skeletal muscles- voluntary muscles Skeletal muscles- voluntary muscles example: muscles attached to bonesexample: muscles attached to bones

Function of Skeletal MusclesFunction of Skeletal Muscles

1) Help maintain homeostasis1) Help maintain homeostasis

2) Produce body movements2) Produce body movements

Skeletal MusclesSkeletal Muscles

There are more than 600 muscles in the There are more than 600 muscles in the body.body.

40 to 50 percent of our body is skeletal 40 to 50 percent of our body is skeletal muscle.muscle.

Connective tissue componentsConnective tissue components

Endomysium- covers Endomysium- covers specialized skeletal specialized skeletal muscle fibersmuscle fibers

Perimysium- binding Perimysium- binding together fasciclestogether fascicles

Epimysium- sheath Epimysium- sheath covering the muscle covering the muscle as a wholeas a whole

Three ways muscles are arrangedThree ways muscles are arranged

1) Size- small to large masses1) Size- small to large masses

2) Shape- broad, narrow, long, tapering, 2) Shape- broad, narrow, long, tapering, short, blunt, triangular, quadrilateral, short, blunt, triangular, quadrilateral, irregular, flat sheets, or bulky massesirregular, flat sheets, or bulky masses

3) Arrangement- parallel to long axis, 3) Arrangement- parallel to long axis, converge to a narrow attachment, oblique, converge to a narrow attachment, oblique, pennate, bipennate, or curvedpennate, bipennate, or curved

Attachment of musclesAttachment of muscles

1) Origin- point of 1) Origin- point of attachment that does attachment that does not move when the not move when the muscle contractsmuscle contracts

2) Insertion- point of 2) Insertion- point of attachment that attachment that moves when muscles moves when muscles contractcontract

Muscle actionsMuscle actions

1) Prime movers (agonist)- muscle or group of muscles 1) Prime movers (agonist)- muscle or group of muscles that directly performs a specific movementthat directly performs a specific movement2) Antagonist- muscle that, when contracting, directly 2) Antagonist- muscle that, when contracting, directly oppose prime movers; relax while prime mover (agonist) oppose prime movers; relax while prime mover (agonist) is contracting to produce movement; provide precision is contracting to produce movement; provide precision and control during contraction of prime moversand control during contraction of prime movers3) synergists- muscles that contract at the same time as 3) synergists- muscles that contract at the same time as the prime movers; they facilitate prime mover actions to the prime movers; they facilitate prime mover actions to produce a more efficient movementproduce a more efficient movement4) Fixator muscles- joint stabilizers4) Fixator muscles- joint stabilizers

Lever systemLever system

Composed of 4 Composed of 4 componentscomponents

1) Rigid bar (bone)1) Rigid bar (bone)

2) Fulcrum (F) around 2) Fulcrum (F) around which the rod moves which the rod moves (joint)(joint)

3) Load (L) that is moved 3) Load (L) that is moved

4) Pull (P) that produces 4) Pull (P) that produces movement (muscle movement (muscle contraction)contraction)

Types of leversTypes of levers

1) First class lever- 1) First class lever- fulcrum lies between fulcrum lies between pull and the loadpull and the load

Not abundant in the Not abundant in the human body; serve as human body; serve as levers of stabilitylevers of stability

Types of leversTypes of levers

2) Second Class 2) Second Class lever- Load lies lever- Load lies between the fulcrum between the fulcrum and the joint at which and the joint at which the pull is exertedthe pull is exerted

Presence of these Presence of these levers in the human levers in the human body is a body is a controversial issuecontroversial issue

Types of leversTypes of levers

Third-class levers- Third-class levers- Pull is exerted Pull is exerted between the fulcrum between the fulcrum and the loadand the load

Permit rapid and Permit rapid and extensive movementextensive movement

Most common type of Most common type of lever found in the lever found in the bodybody

Naming MusclesNaming Muscles

1) Location, function, shape1) Location, function, shape2) Direction of fibers- named according to 2) Direction of fibers- named according to fiber orientationfiber orientation3) Number of heads of divisions3) Number of heads of divisions4) Points of attachment- origin and 4) Points of attachment- origin and insertion pointsinsertion points5) Relative size- small, medium, or large5) Relative size- small, medium, or largeRead page 286 on hints on how to deduce Read page 286 on hints on how to deduce muscle actionmuscle action

Facial MusclesFacial Muscles

Occipitofrontals- Raises eyebrows, Occipitofrontals- Raises eyebrows, wrinkles foreheadwrinkles forehead

Orbicularis oculi- closes eyesOrbicularis oculi- closes eyes

Zygomaticus major- LaughingZygomaticus major- Laughing

Orbicularis oris- Draws lips togetherOrbicularis oris- Draws lips together

Buccinator- Permits smiling (no Coach Buccinator- Permits smiling (no Coach Bryant does not have this muscle)Bryant does not have this muscle)

Muscles for MastificationMuscles for Mastification

Masseter- Closes jawMasseter- Closes jaw

Temporalis- Closes jawTemporalis- Closes jaw

Muscles that move headMuscles that move head

Sternocleidomastoid- Flexes head, one Sternocleidomastoid- Flexes head, one muscle alone, rotates head toward muscle alone, rotates head toward opposite sideopposite sideSemispinalis capitis- Extends head; bends Semispinalis capitis- Extends head; bends it laterallyit laterallySplenius capitis- Extends head/ Bends Splenius capitis- Extends head/ Bends and rotates head toward same side as and rotates head toward same side as contracting musclecontracting muscleLongissimus capitis- Extents headLongissimus capitis- Extents head

Muscles of the ThoraxMuscles of the Thorax

External intercostals- Elevate ribsExternal intercostals- Elevate ribs

Internal intercostals- Depress ribsInternal intercostals- Depress ribs

Diaphragm- Enlarges thorax, causing Diaphragm- Enlarges thorax, causing inspirationinspiration

Muscles of the Abdominal WallMuscles of the Abdominal Wall

External oblique- Compresses abdomen/ External oblique- Compresses abdomen/ rotates trunk laterallyrotates trunk laterally

Internal oblique- same as external obliqueInternal oblique- same as external oblique

Transverse abdominis- same as external Transverse abdominis- same as external obliqueoblique

Rectus abdominis- same as external Rectus abdominis- same as external obliqueoblique

Muscles moving on Shoulder GirdleMuscles moving on Shoulder Girdle

Trapezius- Raises or lowers shoulder and Trapezius- Raises or lowers shoulder and shrugs themshrugs themPectoralis minor- Pulls shoulder down and Pectoralis minor- Pulls shoulder down and forwardforwardSerratus anterior- Pulls shoulder down and Serratus anterior- Pulls shoulder down and forward; abducts and rotates it upwardforward; abducts and rotates it upwardLevator scapulae- Elevates and retracts scapula Levator scapulae- Elevates and retracts scapula and abducts neck.and abducts neck.Rhomboid major and minor- Retracts, rotates, Rhomboid major and minor- Retracts, rotates, fixes scapulafixes scapula

Muscles moving upper armMuscles moving upper arm

Pectoralis major- Flexes upper arm, Pectoralis major- Flexes upper arm, Adducts upper arm anteriorlyAdducts upper arm anteriorly

Latissimus dorsi- Extends upper arm, Latissimus dorsi- Extends upper arm, Adducts upper arm posteriorlyAdducts upper arm posteriorly

Deltoid- Abducts upper armDeltoid- Abducts upper arm

Coracobrachialis- AdductionCoracobrachialis- Adduction

Supraspinatus- Assist in abducting armSupraspinatus- Assist in abducting arm

Teres minor- rotates arm outwardTeres minor- rotates arm outward

Upper arm cont.Upper arm cont.

Teres major- Assist in extension, Teres major- Assist in extension, adduction, and medial rotation of armadduction, and medial rotation of arm

Infraspinatus- Rotates arm outwardInfraspinatus- Rotates arm outward

Subscapularis- medial rotationSubscapularis- medial rotation

Muscles moving the ForearmMuscles moving the Forearm

Biceps brachii- flexes supinated forearmBiceps brachii- flexes supinated forearm

Brachialis- flexes pronated forearmBrachialis- flexes pronated forearm

Brachioradialis- flexes semipronated or Brachioradialis- flexes semipronated or semisupinated forearmsemisupinated forearm

Triceps brachii- Extends lower armTriceps brachii- Extends lower arm

Pronator teres- Pronates and flexer forearmPronator teres- Pronates and flexer forearm

Pronator quadratus- Pronates forearmPronator quadratus- Pronates forearm

Supinator- Supinates forearmSupinator- Supinates forearm

Muscles that move the handMuscles that move the hand

Flexor carpi radialis- Flexes hand/forearmFlexor carpi radialis- Flexes hand/forearmFlexor carpi ulnaris- Flexes hand/ adducts Flexor carpi ulnaris- Flexes hand/ adducts handhandExtensor carpi radialis brevis- Extends Extensor carpi radialis brevis- Extends handhandExtensor carpi ulnaris- Extends hand/ Extensor carpi ulnaris- Extends hand/ Adducts handAdducts handFlexor digitorum- flexes fingersFlexor digitorum- flexes fingersExtensor digitorum- extends fingersExtensor digitorum- extends fingers

Muscles that move thigh Muscles that move thigh

Iliopsoas- Flexes thighIliopsoas- Flexes thigh

Rectus femoris- Flexes thigh/ extends lower legRectus femoris- Flexes thigh/ extends lower leg

Gluteal muscles (maximus- extends thigh/ Gluteal muscles (maximus- extends thigh/ medius- abducts thigh/ minimus- abducts thigh)medius- abducts thigh/ minimus- abducts thigh)

Tensor fasciae latae- abducts thighTensor fasciae latae- abducts thigh

Adductor group- (brevis/longus/mangus- Adductor group- (brevis/longus/mangus- adducts thigh)adducts thigh)

Gracilis- adducts tigh and flexes and adducts legGracilis- adducts tigh and flexes and adducts leg

Muscles that move lower legMuscles that move lower leg

Quadriceps femoris group:Quadriceps femoris group:

Rectus femoris- Flexes thigh/ extends legRectus femoris- Flexes thigh/ extends leg

Vastus lateralis- Extends legVastus lateralis- Extends leg

Vastus medialis- Extends legVastus medialis- Extends leg

Vastus intermedius- Extends legVastus intermedius- Extends leg

Sartorius- Adducts and flexes legSartorius- Adducts and flexes leg

Muscles moving lower leg cont.Muscles moving lower leg cont.

Hamstring group:Hamstring group:

Biceps femoris- Flexes legBiceps femoris- Flexes leg

Semitendinosus- Extends thighSemitendinosus- Extends thigh

Semimembranosus- Extends thighSemimembranosus- Extends thigh

Muscles move the footMuscles move the foot

Tibialis anterior- Flexes/ Inverts footTibialis anterior- Flexes/ Inverts foot

Gastrocnemius- Extends foot/ Flexes lower legGastrocnemius- Extends foot/ Flexes lower leg

Soleus- Extends foot (planter flexion)Soleus- Extends foot (planter flexion)

Peroneus longus- extends footPeroneus longus- extends foot

Peroneus brevis- Flexes footPeroneus brevis- Flexes foot

Peroneus tertius- Flexes footPeroneus tertius- Flexes foot

Extensor digitorum longus- Dorsiflexion of foot/ Extensor digitorum longus- Dorsiflexion of foot/ extension of toesextension of toes