Chapter 8 Flashcards


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Muscles
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1

Cardiac muscle makes most of its ATP via anaerobic pathways.

False

2
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The protein actin is indicated by which letter?

A

3

Peristalsis is characteristic of smooth muscle.

True

4

Immediately following the arrival of the stimulus at a skeletal muscle cell there is a short period called the ________ period during which the neurotransmitter is released by exocytosis, diffuses across the synaptic cleft, and binds to its receptors.

latent

5

Binding of calcium to calmodulin is a step in excitation-contraction coupling of ________ cells.

smooth muscle

6

Which type of muscle CANNOT contract without being stimulated by the nervous system?

skeletal

7

Muscle tissue has all of the following properties except ________.

secretion

8

Once a motor neuron has fired, all the muscle fibers in a muscle contract.

False

9

What structure in skeletal muscle cells functions in calcium storage?

sarcoplasmic reticulum

10

Myoglobin ________.

stores oxygen in muscle cells

11
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In which phase of the muscle twitch shown in the above figure would the maximum amount of ATP be consumed by myosin head groups?

B

12
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The connective tissue that covers structure A is continuous with which of the following?

tendon

13

Which of the following surrounds the individual muscle cell?

endomysium

14

The major role of the sarcoplasmic reticulum is to regulate ________.

intracellular levels of Ca2+

15

When a muscle is unable to respond to stimuli temporarily, it is in which of the following periods?

refractory period

16

What produces the striations of a skeletal muscle cell?

the arrangement of myofilaments

17

In an isotonic contraction, the muscle ________.

changes in length and moves the "load"

18

The contractile units of skeletal muscles are ________.

myofibrils

19
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If both of the neurons in the figure were activated, more muscle fibers would contract than if either neuron alone were active. This mechanism for control of the force of muscle contraction is known as ______.

recruitment

20

What is the functional unit of a skeletal muscle called?

a sarcomere

21
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Which lettered protein functions as a motor protein?

C

22

During muscle contraction, myosin cross bridges attach to which active sites?

actin filaments

23

Most skeletal muscles contain ________.

a mixture of fiber types

24

The smallest contractile unit of a muscle fiber is ________.

the sarcomere

25
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The protein troponin is shown in this figure to be bound to which substance?

calcium ion

26

Although there are no sarcomeres, smooth muscle still possesses thick and thin filaments.

True

27
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Which of the following describes the neurons shown in this figure?

somatic motor neurons

28

What is the functional role of the T tubules?

enhance cellular communication during muscle contraction

29

A muscle that is lengthening while it produces tension is performing a(an) ________ contraction.

eccentric

30

A contraction in which the muscle does not shorten but its tension increases is called isometric contraction.

True

31

Choose the FALSE statement.

Skeletal muscle cells use creatine phosphate instead of ATP to do work.

32

The major function of the sarcoplasmic reticulum in muscle contraction is to ________.

regulate intracellular calcium concentration

33

Three discrete types of muscle fibers are identified on the basis of their size, speed, and endurance. Which of the following athletic endeavors best represents the use of red fibers?

a long, relaxing swim

34
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What cellular event is indicated by A?

exocytosis

35

During isometric contraction, the energy used appears as movement.

False

36

Isometric contraction leads to movement of a load.

False

37

Which of the following is CORRECTLY paired?

skeletal muscle: voluntary control

38

The distance between Z discs ________ during muscle contraction.

decreases

39
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What event directly triggers the release of neurotransmitter shown in A?

diffusion of Ca2+ into the axonal terminus

40

After nervous stimulation stops, what prevents ACh in the synaptic cleft from continuing to stimulate contraction

acetylcholinesterase destroying the ACh

41

Which statement accurately describes the event indicated by B?

Binding of acetylcholine to a receptor triggers the opening of an ion channel.

42
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Which of the following is the smallest structural unit in which the distinctive striated bands characteristic of skeletal muscle are observed?

D

43

The response of a motor unit to a single action potential of its motor neuron is called ________.

a muscle twitch

44

The force of muscle contraction is controlled by multiple motor unit summation or recruitment.

True

45
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How many motor units are illustrated in the figure?

2

46

Which muscle cells have the greatest ability to regenerate?

Smooth

47

An increase in the calcium ion level in the sarcoplasm starts the sliding of the thin filaments. When the level of calcium ions declines, sliding stops.

True

48

The connective tissue sheaths of skeletal muscle, in order from internal to external, are the ________.

endomysium, perimysium, and epimysium

49

Smooth muscles are able to regenerate throughout life.

True

50

What is a cross bridge cycle?

It is the cycle in which an energized myosin head binds to actin and performs a power stroke, then binds to ATP in order to detach and re-energize.