Chapter 10

Question 1

How do muscles move body parts?

Answer 1

1. when they contract they shorten

2. when they shorten they pull on bone

Question 2

Can muscles push?

Answer 2

no, only pull forcefully

Question 3

When muscles work in opposing pairs what is they called? give an example

Answer 3

antagonistic pairs

eg. biceps (flexion) & triceps (extension)

Question 4

Muscles usually stretch across the joint. Where do they attach?

Answer 4

1. origin - end of muscle that does not move

2. insertion - end of muscle that does move

Question 5

What direction does the insertion move?

Answer 5

insertion moves toward the origin when muscle shortens and pulls bone with it

Question 6

What are the 5 functional groups?

Answer 6

1. prime movers
2. antagonists
3. reversal of roles
4. synergists
5. fixators

Question 7

What are the prime movers?

Answer 7

they provide the major force for producing a specific movement

Question 8

What are the antagonists?

Answer 8

oppose or reverse a particular movement

Question 9

What is reversal of roles?

Answer 9

when the prime movers and antagonists can reverse roles

Question 10

What are synergists? and what is their purpose

Answer 10

they add force to a movement: assist the prime mover

they reduce undesirable or unnecessary movement

Question 11

What are fixators? and what is their purpose

Answer 11

they are synergists that immobilize a bone or muscle’s origin

they stabilize a joint - maintaining upright posture

Question 12

What are the 7 criteria used for naming a muscle? and give example

Answer 12

1. location - brachialis
2. shape - deltoid (triangle)
3. relative size - gluteus maximus
4. direction of fiber - external oblique
5. number of origins - triceps
6. location of attachments - sternocleidomastoid
7. action - adductor

Question 13

What is the muscle dependent on in order to carry out a function?

Answer 13

1. position of the muscle
2. arrangement of fascicles
3. lever systems

Question 14

What does a muscle that crosses on the anterior side produce?

Answer 14

flexion

Question 15

What does a muscle that crosses on the posterior side produce?

Answer 15

extension

Question 16

What does a muscle that crosses on the lateral side produce?

Answer 16

abduction

Question 17

What does a muscle that crosses on the medial side produce?

Answer 17

adduction

Question 18

Where are circular fasicles found?

Answer 18

around body openings (ie. mouth)

Question 19

Where are convergent fasicles found?

Answer 19

converge toward a single narrow tendon (ie. pectoralis major)

Question 20

Where are parallel fasicles found?

Answer 20

parallel to the long axis of a strap like muscle (ie. sartorius)

Question 21

Where is fusiform fasicles found?

Answer 21

spindle-shapes muscles with parallel fibers (ie. biceps)

Question 22

Where are pennate fasicles found?

Answer 22

these are short fasicles that attach obliquely to a central tendon running the length of the muscle

Question 23

Name the three types of pennate fasicles and describe.

Answer 23

1. unipennate - fascicles insert into one side only of tendon
2. bipennate - fascicles insert from both sides
3. multipennate - like many feathers side by side (eg. deltoid)

Question 24

What are the 4 components of a lever system?

Answer 24

1. lever
2. fulcrum
3. effort
4. load

Question 25

What is the lever?

Answer 25

rigid bone that moves on a fixed point or fulcrum

Question 26

What is the fulcrum?

Answer 26

the pivot point (joint, articulation)

Question 27

What is the effort?

Answer 27

force (supplied by muscle contraction) applied to a lever to move a resistance

Question 28

What is the load?

Answer 28

resistance moved by the effort (bones & tissues plus any added weight)

Question 29

What are the 3 lever systems?

Answer 29

1. first class 2. second class 3. third class

Question 30

What is a first class lever? and give example

Answer 30

fulcrum (joint) between load and effort | (ie. scissors

Question 31

What is a second class lever? and give example

Answer 31

load between fulcrum (joint) and effort | ie. wheel barrow, standing on tip toe

Question 32

What is a third class lever? and give example

Answer 32

effort applied between fulcrum and load | ie. tweezers, flexing an arm

Question 33

What is the lever system called that works with a mechanical advantage? and why are they called this?

Answer 33

power levers | because they move a big load with a small effort but they are slow (ie. jacking up a car)

Question 34

What are other levers called that work with a mechanical disadvantage? and why?

Answer 34

speed levers | they are faster but take move effort to move a small load (ie. move a pile of dirt with a shovel)

Question 35

Where do muscles of facial expression insert into?

Answer 35

into the skin