Chapter 8 Test Bank Skeletal Muscle

Front 1

A sarcomere is best described as

Back 1

a unit within a myofibril

Front 2

Myofibrils are composed primarily of

Back 2

actin and myosin

Front 3

A motor unit typically includes

Back 3

one motor neuron and several muscle fibers

Front 4

Endomysium separates individual muscle fibers from each other

True or False

Back 4

True

Front 5

A motor neuron and the muscle fibers that it controls constitute a motor unit

True or false

Back 5

True

Front 6

A broad sheet of dense connective tissue that connects muscle to muscle is called

Back 6

aponeurosis

Front 7

The electrical impulse that triggers a contraction travels deep into a skeletal muscle fiber by means of

Back 7

transverse tubules

Front 8

Neurotransmitter molecules are stored in vesicles within

Back 8

motor neuron endings

Front 9

The enzyme acetylcholinesterase causes acetylcholine to

Back 9

decompose

Front 10

Creatine phosphate

Back 10

supplies energy for the synthesis of ATP

Front 11

Binding sites on the surface of actin allow the formation of cross bridges with molecules of

Back 11

myosin

Front 12

The amount of oxygen needed to support the conversion of lactic acid to glucose by the liver is called the

Back 12

oxygen debt

Front 13

A muscle cramp is most likely due to a temporary lack of

Back 13

ATP

Front 14

In the initiation of muscle contraction, calcium ions bind to tropomyosin, exposing active sites on actin for cross bridge formation

True or false

Back 14

False

Front 15

The enzyme ATPase occurs in the globular portion of myosin molecules.

True or false

Back 15

True

Front 16

A C H released by a motor neuron crosses the synaptic cleft and reaches the motor end plate by diffusion

True or false

Back 16

True

Front 17

An example of a partial but sustained contraction of a whole muscle is

Back 17

eye blinking

Front 18

The characteristic reddish brown color of skeletal muscle comes from

Back 18

myoglobin

Front 19

The threshold stimulus is the

Back 19

minimum strength of stimulus required to cause muscle fiber contraction to occur

Front 20

The botulinum toxin that causes botulism acts by blocking acetylcholine receptors on the motor end plate

What is an example of this?

Back 20

muscle weakness or paralysis

Front 21

Rigor mortis that occurs in skeletal muscles a few hours after death is due to

Back 21

a lack of ATP increased membrane permeability to calcium ions

Front 22

ATP is necessary for muscle relaxation

True or false

Back 22

True

Front 23

During anaerobic respiration, pyretic acid molecules are converted into molecules of

Back 23

lactic acid

Front 24

Anaerobic muscle fatigue is most likely due to an accumulation of

Back 24

lactic acid

Front 25

The increase in the number of motor units activated as a result of more intense stimulation is called

Back 25

recruitment

Front 26

In a recording of a muscle twitch, the delay between the time a stimulus is applied and the time the muscle responds is called the

Back 26

latent period

Front 27

Activities such as distance swimming and distance running are most likely to stimulate development of

Back 27

slow fatigue resistant muscle fibers

Front 28

When a muscle undergoes atrophy in response to disuse

Back 28

the muscle gets smaller

Front 29

The minimal strength of stimulation needed to elicit a muscle contraction is called the threshold stimulus

true or false

Back 29

True

Front 30

The time lag between she n a muscle is stimulated and when it begins to contract is called the

Back 30

latent period

Front 31

The rhythmic, wavelike motion produced by visceral smooth muscle is called

Back 31

peristalsis

Front 32

The enlargement of muscle fibers such as a result of exercise is called

Back 32

hypertrophy

Front 33

Multiunit smooth muscle cells

Back 33

respond to stimulation b neurons and certain hormones

Front 34

The term Muscle can refer to

Back 34

a cell

a tissue

an organ

Front 35

Compared to skeletal muscle, smooth muscle

Back 35

contracts more slowly and relaxes more slowly

Front 36

The two neurotransmitters that affect smooth muscle cells are acetylcholine and

Back 36

norepinephhrine

Front 37

Cardiac muscle is located in the walls of the blood vessels

True or false

Back 37

false, heart

Front 38

Muscles that assist a prime mover are called

Back 38

synergists

Front 39

Functions of muscle include

Back 39

the heartbeat

muscle tone

production of heat

moving body parts

Front 40

The movable end of a muscle is attached at its

Back 40

insertion

Front 41

The muscle primarily responsible for opposing a particular action is called the

Back 41

antagonist

Front 42

Identify the three basic types of muscles

Back 42

skeletal, smooth, cardiac

Front 43

Describe the roles of actin and myosin

Back 43

Myosin is thick filaments of myofibrils, actin is thin filaments - type of muscle protein

Front 44

Describe a motor unit

Back 44

a motor neuron and the muscle fibers it controls makes up a motor unit.

when simulated to do so, the muscle fibers of the motor unit contract all at once

Front 45

Muscles are named according to

Back 45

size, shape, location, action, number of attachments or direction of its fiber