CH 10

Question 1

muscle contraction causes…

Answer 1

body movements by pulling one bone or other structure toward another across a movable joint

Question 2

muscle action

Answer 2

the movement accomplished when a muscle contracts

Question 3

Each muscle has 2 points of attachment:

Answer 3

origin and insertion

Question 4

origin

Answer 4

• fixed end (head) of the muscle

- less movable end: muscles can have more than one head (biceps brachii), usually the proximal or medial end of a muscle

Question 5

insertion

Answer 5

• mobile end of the muscle
• end undergoing the greatest movement: usually the distal of lateral end of a muscle, muscles can insert on more than one structure

Question 6

Muscle Structure: Belly

Answer 6

part of the muscle located between the origin and the insertion

Question 7

tendons

Answer 7

long, cable-like structures that connect muscles to bones and other structures

Question 8

aponeuroses

Answer 8

layers of flat sheet-like structures (broad tendons)

Question 9

muscles are usually grouped so that…

Answer 9

the action of one muscle is opposed by that of another muscle or muscle group

Question 10

agonist

Answer 10

• muscle that causes a certain movement

- example: biceps brachii (flexion)

Question 11

antagonist

Answer 11

muscle that acts in opposition to the agonist

example: triceps brachii (extension)

Question 12

muscle function in groups to…

Answer 12

accomplish specific movements

Question 13

synergists

Answer 13

muscles that function together to produce movement

Question 14

prime mover

Answer 14

the synergistic muscle that plays the major role in producing the movent

Question 15

muscles are named according to their:

Answer 15

location
size
origin/insertion
shape
orientation of fasciculi
number of heads
function

Question 16

movements of muscles:

Answer 16

pull
lever
effort
weight 
joints 
bones 
muscles

Question 17

Class I lever

Answer 17

The fulcrum is between the pull and the weight

ex: seesaw

Question 18

In the body, the head functions as a ….

Answer 18

-class 1 lever
fulcrum= atlanto-occipital joint
pull=provided by the posterior neck muscles
weight= the face

Question 19

Class II lever

Answer 19

the weight is between the fulcrum and the pull

ex: wheelbarrow: weight is fulcrum, person lifting on handle bars provides pull

Question 20

Class II lever in the body…

Answer 20

depression of the mandible, opening of the mouth, in this case the whole system is upside down

Question 21

what type of lever is most common?

Answer 21

Class III

Question 22

Class III lever

Answer 22

the pull is applied between the fulcrum and the weight

ex: person shoveling

Question 23

Class III lever in the body

Answer 23

ex: bicep curl

action of biceps brachii acts on the radius to flex the elbow and elevate the hand

force: biceps brachii
lever: radius
fulcrum: elbow
weight: hand