Chapter 11: Muscular System Flashcards

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1
Q

Origin

A

Stationary Bone, usually proximal

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2
Q

Insertion

A

Attachment of muscle’s other tendon to movable bone, usually distal

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3
Q

Belly (Body)

A

Fleshy portion of a muscle between tendons (origin and insertion)

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4
Q

Actions

A

Main movements that occur when muscle contracts

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5
Q

Reverse muscle action (RMA)

A

Actions are reversed in specific actions

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6
Q

Lever system and leverage

A

Bone acts as a lever (Rigid structure moves along a fixed point)

Muscle acts as a fulcrum (Fixed Pont)

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7
Q

Effort

A

Causes movement

Force exerted by muscle contraction

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8
Q

Load/resistance

A

Opposes movement

Weight of body part being moved

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9
Q

Mechanical Advantage

A

only needs a small amount of force to move the load over a small distance

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10
Q

Mechanical Disadvantage

A

Needs a large amount of force to move the load

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11
Q

Lever types (3)

A
  1. First-class lever
  2. Second Class Lever
  3. Third Class Lever
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12
Q

First class lever

A

scissors and seesaws

  1. produces either mechanical advantage or disadvantage
  2. Fulcrum is between Effort and the load
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13
Q

Second class lever

A

wheelbarrow
1. Always produces a mechanical advantage

  1. sacrifices speed and Range Of Motion for force
  2. Load is between fulcrum and the effort
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14
Q

Third class Lever

A
  1. produces mechanical disadvantage
  2. Favors speed and ROM over force
  3. effort between the fulcrum and the load

Most common in the body

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15
Q

Prime Mover or agonist

A

Contracts, causes an action

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16
Q

Antagonist

A

Stretches, yields to Prime mover

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17
Q

Synergists

A

Aid movement of prime mover, prevent unwanted movement

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18
Q

Fixators

A

stabilizes origin of prime mover, so it can move more efficiently

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19
Q

Compartment

A

Group of skeletal muscles, blood vessels and associated nerves have a common function

  • eg. upper limbs: Flexor compartment is anterior and extensor compartment is posterior
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20
Q

Classification of Skeletal Muscles

A

Direction

Size

Shape

Action

of origins

Location

Origin and Insertion

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21
Q

Orbitofrontalis

A

Frontal Belly: Superficial to frontal bone, raises eyebrow and Scalp anteriorly

Occipital Belly: Posterior part, superficial to occipital bone, Draws scalp posteriorly and

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22
Q

orbicularis oculi

A

Closes eye

23
Q

Zygomaticus major

A

Smiling

24
Q

Buccinator

A

Forms cheeks

25
Q

Orbicularis oris

A

Closes and protrudes lips, compresses lips against teeth and shapes lips during speech

26
Q

*Masseter

A

strongest muscle of masication

Origin: Maxilla and zygomatic arch

Insertion: angle and ramus of mandible

Acton: Elevates mandible (closes mouth)

27
Q

*Temporalis

A

Origin: Temporal Bone

Insertion: Coronoid process and ramus of mandible

Action: Elevates and retracts mandible

28
Q

*Sternocleidomastoid

A

Origin:

  sternal head --> manubrium of sternum  
  clavicular head --> medial third of clavicle

Insertion: Mastoid process of temporal bone and lateral half of superior nuchal line of occipital bone

Action: RMA

elevate sternum during forced inhalation

Bilaterally - flexes cervical portion of the vertebral column and flexes the head

Unilaterally - laterally flexes and rotates the head

29
Q

*rectus abdominis

A

long muscle extending whole length of anterior abdominal wall

Origin: pubic crest and pubic symphysis

Insertion: cartilages of ribs 5-7 and the xiphoid process

Action: Flexes vertebral column (esp. lumbar), compresses abdomen to aid in defecation, urination, forced exhalation and childbirth (RMA: -exes pelvis on the vertebral column)

30
Q

external oblique

A

superficial muscle - fascicles extend inferiorly and medially

31
Q

Internal oblique

A

Intermediate muscle - fascicles extend at right angles to external obliques

32
Q

transversus abdominis

A

deep muscle, fascicles directed transversely around abdominal wall
Together with internal and external oblique, structural arrangement of muscle fascicles in different directions provide considerate protection to abdominal viscera

Form linea alba
During forceful exhalation – compresses abdomen

33
Q

diaphragm

A

important muscle that powers breathing - separates thoracic and abdominal cavities

Convex superior surface - forms floor of thoracic cavity

Concave inferior surface - forms roof of abdominal cavity

Contraction of diaphragm causes it to flatten and increases vertical height in thoracic cavity (inhalation)

Relaxation of diaphragm causes it to move superiorly and decrease in height in thoracic cavity (exhalation)

34
Q

external intercostal

A

Elevate ribs during inhalation - expands thoracic cavity

During relaxation: depress ribs and decreases anteroposterior and lateral dimensions of thoracic cavity (exhalation)

35
Q

Internal Inter costal

A

Decreases size of thoracic cavity during forced exhalation

36
Q

Pectoralis minor

A

Draws scapula up towards thorax

37
Q

*trapezius

A

extends from the skull and vertebral column medially and to the shoulder girdle laterally most superficial back muscle

Covers posterior neck region and superior portion of the trunk (found on both sides - form a diamond shape)

Origin: superior nuchal line of occipital bone, ligamentum nuchae and spines of c7-t12

Insertion: clavicle and acromion and spine of scapula superior fibers

Action: upward rotation of scapula middle fibers - adduction of scapula inferior fibers - depress and upward rotation of scapula superior and inferior fibers - upward rotation, stabilizes scapula

o RMA - superior fibers help extend head

38
Q

*levator scapulae

A

Origin: transverse processes of c1-c4

Insertion: superior vertebral border of scapula

Action: elevates scapula and rotates downward

39
Q

rhomboid major

A

elevates and adducts scapula rotates it downward stabilizes scapula

40
Q

*pectoralis major

A

origin: clavicular head, sternum and costal cartilages of ribs 2-6, sometimes ribs 1-7 (sternocostal head)

Insertion: greater tubercle, lateral lip of intertubercular sulcus of humerus

Action: adducts and medially rotates arm at shoulder joint clavicular head - -exes arm sternocostal head extends -exed arm to side of trunk

41
Q

latissimus dorsi

A

Action: extends, adducts and medially rotates arm at shoulder joint

Draws arm inferiorly and posteriorly o

RMA: elevates vertebral column and torso

42
Q

Deltoids

A

origin (3):

  1. acromial extremity of clavicle (anterior fibers)
  2. Acromion of scapula (lateral fibers)
  3. Spine of scapula (posterior fibers)

Insertion: deltoid tuberosity of humerous

Action:

  1. lateral fibers abduct arm at shoulder joint
  2. anterior fibers - -ex and medially rotate arm at shoulder joint
  3. posterior fibers - extend and laterally rotate arm at shoulder joint
43
Q

subscapularis

A

Medially rotates arm at shoulder joint

44
Q

Supraspinatus

A

Origin: supraspinous fossa of scapula

Insertion: greater tubercle of humerus

Action: assists deltoid muscle in abducting arm at shoulder joint

45
Q

infraspinatus

A

Laterally rotates arm at shoulder joint

46
Q

teres major

A

Extends arm at shoulder joint assists adduction and medial rotation of arm at shoulder joint

47
Q

Teres minor

A

Laterally rotates and extends arm at shoulder joint

48
Q

biceps brachii

A

Origin (2):

  1. Long head - tubercle above glenoid cavity of scapula
  2. short head - coracoid process of scapula

Insertion: radial tuberosity of radius and bicipital aponeurosis

Action: Flexes forearm at elbow joint Supinates forearm at radioulnar joints Flexes arm at shoulder joint

49
Q

Brachialis

A

Deep to biceps brachii, powerful -exor of the forearm “workhorse”

50
Q

Brachioradialis

A

Flexes forearm at elbow joint - supinates and pronates forearm at radioulnar joints to neutral positon

51
Q

*triceps brachii

A

Origin (3):

  1. Long head - infraglenoid tubercle
  2. Lateral head - lateral and posterior surface of humerus
  3. medial head - posterior surface of humerus inferior to a groove for the radial nerve

Insertion: olecranon of ulna

Action: extends forearm at elbow joint, extends arm at shoulder joint

52
Q

pronator teres

A

Pronates forearm at radioulnar joints and weakly -exes

53
Q

supinator

A

supinates forearm at radioulnar joints use it when you screw in a screw driver or open a corkscrew