A&P Chp. 10: The Muscular System

Question 1

How Skeletal Muscles Produce Movement

Answer 1

1. Muscles exert force on tendons that pull on bones
2. Muscles usually span a joint
3. Muscle contraction changes the angle or position of one bone relative to another

Question 2

Origin

Answer 2

The attachment of the muscle to the bone that remains stationary

Question 3

Insertion

Answer 3

the attachment of the muscle to the bone that moves

Question 4

Belly

Answer 4

the fleshy part of the muscle between the tendons of origin and/or insertion

Question 5

Interactions of Skeletal Muscles in the Body

Answer 5

1. Prime Mover (agonist): the principle muscle that causes a movement
2. Antagonist: the principle muscle that causes the opposite movement
3. Synergists: muscles that assist the prime mover
4. Fixators: synergists that stabilize the origin of a prime mover

Question 6

Arrangement of Fasicles

Answer 6

Parallel: straplike
Fusiform: spindle shaped
Pennate: feather shaped
Bipennate: two feathers
Multipennate: multiple feathers
Convergent: all muscles converge into one point
Circular: go all in circle
Range of Motion: long fibers = long range of motion
Power: many fibers = great power

Question 7

Lever Systems and Leverage

Answer 7

Lever: a rigid rod that moves on some fixed point
Fulcrum: joint, a fixed point
Resistance: the force that opposes movement; the load
Effort: the force exerted to achieve a movement

Question 8

Mechanical Advantage

Answer 8

Load is near fulcrum, effort is far away
Only a small effort is required to move an object
Allows a heavy object to be moved with a small effort
Ex: car jack

Question 9

Mechanical Disadvantage

Answer 9

Load is far from the fulcrum, effort is near the fulcrum
A large effort is required to move the object
allows object to be moved rapidly
Throwing a baseball