General Biomechanical Principles

Question 1

What is each skeletal muscle composed of?

Answer 1

fascicles

Question 2

Define a fascicle.

Answer 2

a bundle of muscle fibers

Question 3

What do muscle fibers contain?

Answer 3

myofibrils

Question 4

What are myofibrils composed of?

Answer 4

myofilaments

Question 5

List the breakdown of a muscle.

Answer 5

Muscle belly to epimysium to fascicles and perimysium to endomysium and myofiber to myofibril to sarcomere to actin and myosin

Question 6

What does tendons attach?

Answer 6

muscle to bone, skin, or another muscle

Question 7

Describe tendons.

Answer 7

usually have a thick cord-like structure

Question 8

What is an aponeurosis?

Answer 8

thin flattened sheet of tendons

Question 9

Give an example of a tendon.

Answer 9

Achilles tendon

Question 10

Where would one find an aponeurosis?

Answer 10

Abdominal muscles

Question 11

What do ligaments attach?

Answer 11

Bone to bone

Question 12

Most skeletal muscles extend ________ and cross ______.

Answer 12

between bones, at least one movable joint

Question 13

Upon contraction, one of the bones _____ while the other bone usually remains _____.

Answer 13

moves, fixed

Question 14

Define origin.

Answer 14

less movable attachment of a muscle

Question 15

Define insertion.

Answer 15

more movable attachment of muscle

Question 16

Where does the origin usually lie?

Answer 16

proximal to the insertion

Question 17

True or false the insertion is pulled toward the origin.

Answer 17

True

Question 18

List the 4 organizational patterns in fascicles of muscle fibers.

Answer 18

Cicular, convergent, parallel, pennate

Question 19

Describe a circular organizational pattern.

Answer 19

muscle is also called a sphincter because contraction of the muscle closes off the opening

Question 20

Describe a convergent organizational pattern.

Answer 20

muscle has widespread muscle fibers that converge on a common attachment site and are often triangular in shape.

Question 21

Describe a parallel organizational pattern.

Answer 21

fascicles run parallel to its long axis; have a central body called the belly or gaster

Question 22

Describe a pennate organizational pattern.

Answer 22

have one or more tendons extending through their body and the fascicles are arranged at an oblique angle to the tendon

Question 23

Give an example of a convergent muscle.

Answer 23

pectoralis major

Question 24

Give an example of a circular muscle.

Answer 24

orbicularis oris

Question 25

Give examples of parallel muscles.

Answer 25

stemocleidomastoid, biceps brachii

Question 26

Give examples of pennate muscles.

Answer 26

deltoid (multi), flexor pollicis longus (uni), rectus femoris (bi)

Question 27

Define effort.

Answer 27

load arm; work required (muscles do the work)

Question 28

Define load.

Answer 28

resistance arm; what is being resisted or being moved (the body part)

Question 29

Define fulcrum.

Answer 29

point of movement (the joint)

Question 30

Define resistance arm.

Answer 30

distance between axis and point of resistance application

Question 31

Define force arm.

Answer 31

distance between axis and point of force

Question 32

List the 3 classes of levers in the body.

Answer 32

first, second, and third

Question 33

Define a first class lever system and give and example.

Answer 33

has a fulcrum in the middle, between the force and the resistance

example: the head

Question 34

Define a second class lever system and give and example.

Answer 34

resistance is between the fulcrum and the applied force

example: raising the body up, balancing on the balls of the feet

Question 35

Define a third class lever system and give and example.

Answer 35

force is applied between the resistance and the fulcrum

example: doing dumbbell curls - biceps

Question 36

What is the most common lever system in the body?

Answer 36

third class

Question 37

How does bears’ biceps differ than humans? What does this produce?

Answer 37

In bears the bicep tendon inserts further down (distally) on the forearm, resulting in very strong, but relatively slower flexion.

Question 38

What are the three primary types of actions of skeletal muscles?

Answer 38

agonists, antagonists, synergists

Question 39

What is the action of an agonist?

Answer 39

contracts muscle to produce a particular movement

Question 40

What is the action of an antagonist?

Answer 40

opposes those actions of the agonist

Question 41

What is the action of a synergist?

Answer 41

• assist the prime mover in performing its action
• the contraction contrbutes to tension exerted close to the insertion of the muscle or stabilizes the point of origin
• may also assist an agonist by preventing movement at a joint and thereby stabilizing the origin of the agonist
• called fixators