Ch. 11 - The Muscular System

Question 1

How do skeletal muscles produce movement?

Answer 1

muscles PULL on tendons, which pull o bones, skin, etc

Question 2

What is the origin and insertion?

Answer 2

origin: attachment to the bone that does NOT move when the muscle shortens; usually proximal
insertion: attachment to moveable bone; usually distal

Question 3

What are 2 muscle attachment sites?

Answer 3

muscle belly - fleshy part of muscle in bt attachment sites

tendons - attach muscles to bones

Question 4

What is a lever and fulcrum?

Answer 4

lever - rigid structure moves around the fulcrum (fixed point)

Question 5

What are the 2 forces the lever is acted on?

Answer 5

LOAD - opposes movement

EFFORT - causes movement

Question 6

What must exceed what to allow movement?

Answer 6

effort must exceed load

Question 7

What do bones, joints, and muscle contraction serve as in lever systems?

Answer 7

bones - lever

joints - fulcrum

force of musc contraction - effort

Question 8

What is a mechanical advantage?

Answer 8

distance bt fulcrum and effort > distance bt fulcrum and load

Question 9

What is a mechanical disadvantage?

Answer 9

distance bt fulcrum and effort < distance bt fulcrum and load

Question 10

What is a first class lever?

Answer 10

fulcrum is in bt effort and load (EFL)

- can produce mech adv/disadv

Question 11

What is a second class lever?

Answer 11

load is in bt fulcrum and effort (FLE)

• always produce mech adv; resistance is always closer to fulcrum than effort is

Question 12

What is a third class lever?

Answer 12

effort in bt fulcrum and load (FEL)

- always produce mech disadv; effort is always closer to fulcrum than resistance is

Question 13

What are adv and disadv of third class levers?

Answer 13

adv: increase range, control, and speed of movement
disadv: requires more effort to move load

Question 14

What happens to a muscle’s length when it contracts?

Answer 14

shortens to about 70% of its length

-

Question 15

What are agonists and antagonists in muscle contraction?

Answer 15

agonist - main contracting muscle/prime mover

antagonist - performs opposite movement

*one contracts, the other relaxes (e.g. flexion vs. extension)

Question 16

What is the difference between synergists and fixators?

Answer 16

S - muscles that assist prime mover or prevent unwanted movements

F - stabilize origin of prime mover

Question 17

What are the 7 facial muscles? (2 - mandible, 1 - head)

Answer 17

occipitofrontalis, orbicularis oculi, orbicularis oris, platysma, masseter, temporalis, sternocleidomastoid

Question 18

What are the 6 eye muscles?

Answer 18

inferior oblique, inferior rectus, lateral rectus, medial rectus, superior oblique, superior rectus

Question 19

10 chest and abdominal muscles

Answer 19

diaphragm, external/internal intercostals, external/internal obliques, pectoralis minor, rectus abdominis, serratus anterior, transversus abdominis, trapezius

Question 20

6 arm muscles

Answer 20

biceps brachii, brachioradialis, deltoid, latissimus dorsi, pectoralis major, triceps brachii

Question 21

9 leg muscles

Answer 21

gastrocnemius, gluteus maximus, gluteus medius, gracilis, hamstrings (3), quadriceps (4), sartorius, soleus, tibialis anterior

Question 22

Identify and describe occipitofrontalis

Answer 22

frontal and occipital belly, draws scalp ant/post, raises brows

Question 23

Identify and describe orbicularis oculi

Answer 23

closes eye

Question 24

Identify and describe orbicularis oris

Answer 24

closes lips (kiss!), compresses lips against teeth, shapes lip during speech

Question 25

Identify and describe platysma

Answer 25

depresses mandible, raws outer part of lower lip inf/post (pouting)

Question 26

Identify and describe masseter

Answer 26

elevates mandible, closes mouth

Question 27

Identify and describe temporalis

Answer 27

elevates and retracts mandible

Question 28

Identify and describe sternocladimastoid

Answer 28

unilaterally - laterally flexes & rotates head

bilaterally - flexes head + cervical portion of vert column

Question 29

Identify and describe external and internal obliques

Answer 29

unilaterally - flex vert column (esp lumbar portion), rotate vertebral column

bilaterally - compress abdomen, flex vert column

• ext - superior muscle
• int - intermediate muscle

Question 30

Identify and describe diaphragm

Answer 30

contractions during inhalation (expands thoracic cavity)

relaxes during exhalation (decreases vert dimension thoracic cavity)

Question 31

Identify and describe external/internal intercostals

Answer 31

spaces b/t ribs

E - contraction-inhalation, elevates ribs; relaxation-exhalation, depresses ribs

I - contraction draws adj ribs tgt during forced exhalation

Question 32

Identify and describe pectoralis minor

Answer 32

abducts scapula and rotates downward; rotates ribs 3-5 during forced inhalation when scapula is fixed

Question 33

Identify and describe rectus abdominis

Answer 33

compresses abdomen to aid in defecation, urination, forced exhalation, childbirth

Question 34

Identify and describe serratus anterior

Answer 34

abducts scapula and rotates upward; important in horizontal arm movements (pushing, punching)

Question 35

Identify and describe transversus abdominis

Answer 35

compresses abdomen

Question 36

Identify and describe trapezius

Answer 36

upwardly rotate, adduct, depress, stabilize scapula

Question 37

Identify and describe biceps brachii

Answer 37

flexes forearm at elbow joint; supinates forearm at radioulnar joints; flexes arm at shoulder jount

Question 38

Identify and describe brachioradialis

Answer 38

flexes forearm at elbow joint; supinates and pronates forearm at radioulnar joint to neutral pos

Question 39

Identify and describe deltoids

Answer 39

lat - abduct arm at shoulder joint
anterior - flex, medially rotate arm at shoulder joint
posterior - extend and laterally rotate arm at shoulder joint

Question 40

Identify and describe latissimus dorsi

Answer 40

extends, adducts, medially rotates arm at shoulder joint; draws arm inferiorly and posteriorly

Question 41

Identify and describe pectoralis major

Answer 41

whole - adducts, medially rotates arm at shoulder joint

clavicular head - flexes arm

sternocostal head - extends flexed arm to side of trunk

Question 42

Identify and describe triceps brachii

Answer 42

extends forearm at elbow joint and extends arm at shoulder joint

Question 43

Identify and describe gastrocnemius

Answer 43

plantar flexes foot at ankle joint and flexes leg at knee joint

Question 44

Identify and describe gluteus maximus and gluteus medius

Answer 44

max - extends thigh at hip joint and laterally rotates thigh; helps lock knee in extension

med - abducts thigh at hip joint and medially rotates thigh

Question 45

Identify and describe hamstrings (3)

Answer 45

biceps femoris, semitendinosus, semimembranosus

• flexes leg at knee joint and extends thigh at hip joint

Question 46

Identify and describe quadriceps (4)

Answer 46

vastus lateralis/medialis/intermedius, rectus femoris

• extend leg at knee joint; rectus femoris flexes thigh at hip joint

Question 47

Identify and describe sartorius

Answer 47

• weakly flexes leg at knee joint

- weakly flexes, abducts, laterally rotates thigh at hip joint

Question 48

Identify and describe soleus

Answer 48

plantar flexes foot at ankle joint

Question 49

Identify and describe tibialis anterior

Answer 49

dorsiflexes foot at ankle joint and inverts foot at intertarsal joints

Question 50

Identify and describe gracilis

Answer 50

adducts thigh at hip joint, medially rotates thigh, flexes leg at knee joint