Ch. 6 pt 1

Question 1

T/F: There is only one motor end plate per muscle fiber

Answer 1

True

Question 2

Tension is progressively elevated until a maximum value for a fiber is reached

Answer 2

summation

Question 3

prolonged exposure causes fatigue leading to gradual decline in the level of tension produced

Answer 3

tetanus

Question 4

one of the muscle’s characteristic properties, __, is the ability to respond to a stimulus

Answer 4

irritability

Question 5

skeletal motor units in mammals that respond to a single stimulus by developing tension in twitch-like fashion are called __ __ cells.

Answer 5

twitch type

Question 6

rank the types of motor units, placing the ones activates first at the top

Answer 6

1.) type lla, or FOG, fibers
2.) type llb, or FG, fibers

Question 7

a contraction involving the shortening of a muscle is known as a __ contraction

Answer 7

concentric

Question 8

during the elbow flexion phase of a forearm curl, which of the following acts as a primary agonist?

Answer 8

the brachialis

Question 9

parallel elastic component is derived from the __

Answer 9

muscle membranes

Question 10

series elastic component is derived from the __

Answer 10

tendons

Question 11

muscle fibers

Answer 11

threadlike cells of a muscle

Question 12

sarcolemma

Answer 12

membrane surrounding a muscle fiber

Question 13

sarcoplasm

Answer 13

specialized cytoplasm of a muscle fiber

Question 14

T/F: antagonists oppose the actions of agonists by developing eccentric tension the same time that agonists are causing movement

Answer 14

true

Question 15

the fibers of motor units that contract to reach maximum tension quickly after being stimulated

Answer 15

fast twitch type

Question 16

the fibers of motor units that contract to reach maximum tension gradually after being stimulated

Answer 16

slow twitch type

Question 17

the fibers are oriented largely in parallel with the longitudinal axis of muscle

Answer 17

parallel fiber arrangement

Question 18

the fibers lie at an angle to a muscle’s longitudinal axis

Answer 18

pennate fiber arrangement

Question 19

the formula that defines net torque generated in a joint

Answer 19

T⌄m = F⌄m x d⌄t

Question 19

a(n) __ contraction describes a contraction involving no change in muscle length

Answer 19

isometric

Question 20

__ contraction occurs when muscular tension produces a torque larger than the resistive torque at a joint

Answer 20

concentric

Question 21

a(n) __ contraction occurs when an opposing joint torque exceeds that produced by tension in a muscle

Answer 21

eccentric

Question 22

muscles that act to stabilize a body part against a particular force assume the role of __

Answer 22

stabilizer(s)

Question 23

a __ __ refers to a single motor neuron and all muscle fibers it innervates

Answer 23

motor unit

Question 24

what is true about the tension in a twitch fiber following a stimulus of a single nerve impulse

Answer 24

it rises to a peak value in less than 100 msec and then immediately declines

Question 25

what represents torque produced by a muscle at a joint

Answer 25

T⌄m

Question 26

what represents the muscle force

Answer 26

F⌄m

Question 27

what represents muscle moment arm

Answer 27

d⌄t

Question 28

those muscles which prevent unwanted accessory actions produced by agonists play the role of __

Answer 28

neutralizers

Question 29

when rapid, successive impulses activate a fiber already in tension

Answer 29

summation

Question 30

when a fiber is repetitively activated so that its maximum tension level is maintained for a time

Answer 30

tetanus

Question 31

internal forces

Answer 31

due to tension in other muscles

Question 32

external forces

Answer 32

due to the weight of an object being lifted

Question 33

Which of the following is true of motor units?

Answer 33

There is only one motor end plate per muscle fiber

Question 34

The net torque generated at a joint is the __

Answer 34

vector sum of the muscle torque and the resistive torque

Question 35

a muscle that acts to slow or stop the movement of a body segment at a joint plays the role of a(n) __

Answer 35

antagonist

Question 36

T/F: slow twitch (ST) fibers usually fatigue more quickly than do fast twitch (FT) fibers

Answer 36

false