Practice Set 3A

Question 1

What are the functions of skeletal muscle?

Answer 1

Heat production

Blood sugar regulation

Control of body openings and passages

Question 2

The endomysium is a connective tissue sheath that wraps around which of the following?

Answer 2

Muscle fiber

Question 3

Which describes a muscle fascicle?

Answer 3

A bundle of muscle fibers surrounded by connective tissue

Question 4

Which term refers to the loose connective tissue layer that surrounds skeletal muscle fascicles?

Answer 4

Perimysium

Question 5

The structures indicated by the arrows are examples of which of the following?

Answer 5

Tendons

Question 6

Which are functions of skeletal muscle?

Answer 6

Heat production

Movement

Joint stability

Question 7

Which describes the endomysium?

Answer 7

A loose connective tissue layer around each individual muscle cell

Question 8

Which term refers to bundles of muscle fibers, wrapped in connective tissue, within a muscle?

Answer 8

Fascicles

Question 9

What is the perimysium?

Answer 9

A connective tissue sheath bundling many muscle fibers into a fascicle

Question 10

In flexing the elbow, the prime mover is the ______.

Answer 10

brachialis

Question 11

Connective tissue structures that attach bone to muscle are called _____.

Answer 11

tendons

Question 12

Because skeletal muscle is under the conscious control it is said to be ______.

Answer 12

voluntary

Question 13

Muscle cells contain _______ a red pigment that stores oxygen needed for muscular activity.

Answer 13

myoglobin

Question 14

In a myofibril, a thick filament is composed of pairs of _______ molecules intertwined together.

Answer 14

myosin

Question 15

Which term refers to a muscle that produces most of the force during a particular joint action?

Answer 15

Agonist

Question 16

Skeletal muscle exhibits alternating light and dark bands called _______.

Answer 16

striations

Question 17

The portion of a myofibril from one Z disc to the next is called a(n) _________.

Answer 17

sarcomere

Question 18

True or false: Skeletal muscle contraction helps produce body heat.

Answer 18

True

Question 19

What is a motor unit?

Answer 19

All of the muscle fibers innervated by a single motor nerve fiber

Question 20

Muscle cells contain _______, a starch-like carbohydrate that provides energy during intense exercise.

Answer 20

glycogen

Question 21

Which protein makes up the thick filaments of a myofibril?

Answer 21

Myosin

Question 22

A synapse is the point where a nerve fiber meets a target cell. When the target cell is a muscle fiber, this type of synapse is called a _______ junction.

Answer 22

neuromuscular

Question 23

What is the prime mover?

Answer 23

agonist

Question 24

Within skeletal muscle cells, what extends from one Z disc to the next and constitutes one contractile unit?

Answer 24

Sarcomere

Question 25

All of the muscle fibers innervated by a single nerve fiber constitute a ______ unit.

Answer 25

motor

Question 26

What is the indented region of the sarcolemma that participates in the neuromuscular junction called?

Answer 26

Motor end plate

Question 27

Muscle cells contain _______ , a red pigment that stores oxygen needed for muscular activity.

Answer 27

myoglobin

Question 28

The synaptic knob does not touch the muscle fiber but is separated by which structure?

Answer 28

Synaptic cleft

Question 29

What is a neuromuscular junction?

Answer 29

A site where a nerve fiber communicates with a muscle fiber

Question 30

Which term refers to a muscle that produces most of the force during a particular joint action?

Answer 30

Agonist

Question 31

Within a synapse, a neuron ends in a swelling called a(n) ______ terminal.

Answer 31

synaptic, axon, Axon, or Synaptic

Question 32

A synapse is the point where a nerve fiber meets a target cell. When the target cell is a muscle fiber, this type of synapse is called a _______ junction.

Answer 32

neuromuscular

Question 33

What is acetylcholine?

Answer 33

The neurotransmitter released at a neuromuscular junction

Question 34

In flexing the elbow, the prime mover is the ______.

Answer 34

brachialis

Question 35

Regarding skeletal muscle contraction, what is excitation?

Answer 35

The process by which action potentials in a nerve fiber lead to action potentials in a muscle fiber

Question 36

At the synaptic knob of the motor neuron, calcium stimulates exocytosis of the synaptic vesicles to release the neurotransmitter ______ into the synapse.

Answer 36

acetylcholine

Question 37

What is the indented region of the sarcolemma that participates in the neuromuscular junction called?

Answer 37

Motor end plate

Question 38

The synaptic knob does not touch the muscle fiber but is separated by which structure?

Answer 38

Synaptic cleft

Question 39

The neurotransmitter used in a neuromuscular junction is ______.

Answer 39

acetylcholine

Question 40

What is the process by which action potentials of a nerve fiber lead to action potentials in the muscle fiber called?

Answer 40

Excitation

Question 41

When a nerve signal arrives at a synaptic knob, which voltage-gated channels open in the knob?

Answer 41

Calcium

Question 42

In an NMJ, after acetylcholine diffuses across the synaptic cleft, where does it bind to ligand-gated channels?

Answer 42

On the sarcolemma

Question 43

Within a synapse, a neuron ends in a swelling called a(n) ________ terminal.

Answer 43

axon

Question 44

What is excitation-contraction coupling?

Answer 44

The events that link the action potential of the sarcolemma to the activation of the myofilament contraction

Question 45

Action potentials spread across the sarcolemma and continue down which structures into the sarcoplasm?

Answer 45

T tubules

Question 46

Regarding skeletal muscle contraction, what is excitation?

Answer 46

The process by which action potentials in a nerve fiber lead to action potentials in a muscle fiber

Question 47

When acetylcholine binds to its receptors on the motor end plate, an ion channel opens and ______ ions diffuse quickly into the muscle cell.

Answer 47

sodium

Question 48

Which phase of contraction links the action potential in the sarcolemma to the activation of the myofilament?

Answer 48

Excitation-contraction coupling

Question 49

Action potentials cause the opening of voltage-gated sodium ion channels in the ________ tubules. This leads to the opening of calcium ion channels in the terminal cisternae of the sarcoplasmic reticulum.

Answer 49

transverse

Question 50

What is the process by which action potentials of a nerve fiber lead to action potentials in the muscle fiber called?

Answer 50

Excitation

Question 51

What must occur before tropomyosin can shift, revealing the active sites that allow myosin heads to bind to the actin filaments?

Answer 51

Calcium must bind to troponin.

Question 52

When a nerve signal arrives at a synaptic knob, which voltage-gated channels open in the knob?

Answer 52

Calcium

Question 53

During which phase of muscle contraction is calcium transported back into the cisternae and tropomyosin moves back to block the actin active sites?

Answer 53

Relaxation

Question 54

In an NMJ, after acetylcholine diffuses across the synaptic cleft, where does it bind to ligand-gated channels?

Answer 54

On the sarcolemma

Question 55

What is excitation-contraction coupling?

Answer 55

The events that link the action potential of the sarcolemma to the activation of the myofilament contraction

Question 56

The enzyme that breaks down acetylcholine is called

Answer 56

acetylcholinesterase, AChE, or cholinesterase

Question 57

Action potentials spread across the sarcolemma and continue down which structures into the sarcoplasm?

Answer 57

T tubules

Question 58

What occurs when calcium binds to troponin?

Answer 58

The troponin-tropomyosin complex changes shape and exposes the myosin binding sites (active sites).

Question 59

Steps of muscle relaxation in order.

Answer 59

Question 60

What is the role of acetylcholinesterase?

Answer 60

It breaks down ACh, ending muscle stimulation.

Question 61

During relaxation, active-transport pumps in the sarcoplasmic reticulum move which ion from the sarcoplasm into the cisternae?

Answer 61

Calcium

Question 62

During which phase of muscle contraction is calcium transported back into the cisternae and tropomyosin moves back to block the actin active sites?

Answer 62

Relaxation