Deck 9: Muscles and Muscle Tissue

Question 1

Muscle tone is the small amount of tautness or tension in the muscle due to weak, involuntary contractions of its motor units.

Answer 1

True

Question 2

The effect of a neurotransmitter on the muscle cell membrane is to modify its ion permeability properties temporarily.

Answer 2

True

Question 3

One of the functions of skeletal muscle contraction is production of heat.

Answer 3

True

Question 4

A motor neuron and all the muscle cells that it stimulates are referred to as a motor end plate.

Question 5

Cells of unitary smooth muscle are found in the longitudinal and circular muscle layers of the intestine.

Question 6

Most skeletal muscles contain________.

A) a predominance of fast oxidative fibers
B) muscle fibers of the same type
C) a mixture of fiber types
D) a predominance of slow oxidative fibers

Question 7

Muscle cells store more creatine phosphate than ATP resulting in the muscle having a reserve source of energy.

Question 8

During isometric contraction, the energy used appears a s movement.

Question 9

Eccentric contractions are more forceful than concentric contractions.

Question 10

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

Question 11

Peristalsis is characteristic of smooth muscle.

Question 12

Cardiac muscle has a limited regenerative capacity.

Question 13

A resting potential is caused by a difference in the concentration of certain ions inside and outside the cell.

Question 14

What is the role of tropomyosin in skeletal muscles?

A) Tropomyosin is the chemical that activates the myosin heads.
B) Tropomyosin serves as a contraction inhibitor by blocking the actin binding sites on the myosin molecules.
C) Tropomyosin is the receptor for the motor neuron neurotransmitter.
D) Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules.

Question 15

The strongest muscle contractions are normally achieved by ________.

A) increasing stimulus above the treppe stimulus
B) increasing the stimulation up to the maximal stimulus
C) increasing stimulus above the threshold
D) recruiting small and medium muscle fibers

Question 16

When a muscle fiber contracts, the I bands diminish in size, the H zones disappear, and the Abands do not diminish in length.

Question 17

Which muscle cells have the greatest ability to regenerate?

A) no muscle can regenerate
B) smooth
C) cardiac
D) skeletal

Question 18

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

Question 19

Muscle contraction will always promote movement of body parts regardless of how they are attached.

Question 20

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.

Question 21

Myoglobin ________.

A) is a protein involved in the direct phosphorylation of ADP
B) produces the end plate potential
C) breaks down glycogen
D) stores oxygen in muscle cells

Question 22

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

A) contraction
B) latent
C) refractory
D) relaxation

Question 23

During vigorous exercise, there may be insufficient oxygen available to completely break down pyruvic acid for energy. As a result, the pyruvic acid is converted to ________.

A) hydrochloric acid
B) a strong base
C) stearic acid
D) lactic acid

Question 24

What is the functional role of the T tubules?

A) enhance cellular communication during muscle contraction
B) hold cross bridges in place in a resting muscle
C) synthesize ATP to provide energy for muscle contraction
D) stabilize the G and F actin

Question 25

In an isotonic contraction, the muscle ________.

A) does not change in length but increases tension
B) rapidly resynthesizes creatine phosphate and ATP
C) never converts pyruvate to lactate
D) changes in length and moves the "load"

Question 26

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

A) Z discs
B) actin filaments
C) myosin filaments
D) thick filaments

Question 27

What is the primary function of wave summation?

A) prevent muscle fatigue
B) increase muscle tension
C) produce smooth, continuous muscle contract ion
D) prevent muscle relaxation

Question 28

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

A) relaxation period
B) latent period
C) refractory period
D) fatigue period

Question 29

Rigor mortis occurs because ________.

A) sodium ions leak into the muscle causing continued contractions
B) proteins are beginning to break down, thus preventing a flow of calcium ions
C) the cells are dead
D) no ATP is available to release attached actin and myosin molecules

Question 30

Creatine phosphate functions in the muscle cell by ________.

A) forming a chemical compound with actin
B) inducing a conformational change in the myofilaments
C) storing energy that will be transferred to ADP to resynthesize ATP
D) forming a temporary chemical compound with myosin

Question 31

Which of the following surrounds the individual muscle cell?

A) perimysium
B) endomysium
C) fascicle
D) epi mysium

Question 32

The contractile units of skeletal muscles are ________.

A) mitochondria
B) T tubules
C) microtubules
D) myofibrils

Question 33

What does excess postexercise oxygen consumption represent?

A) the difference between the amount of oxygen needed for totally aerobic muscle activity and the amount actually used
B) the amount of oxygen taken into the body immediately after the exertion
C) the amount of oxygen equal to the oxygen already used
D) amount of oxygen needed for aerobic activity to accomplish the same amount of work

Question 34

Which of the following would be recruited later in muscle stimulation when contractile strength increases?

A) large motor units with small, highly excitable neurons
B) motor units with larger, less excitable neurons
C) many small motor units with the ability to stimulate other motor units
D) motor units with the longest muscle fibers

Question 35

The mechanism of contraction in smooth muscle is different from skeletal muscle in that________.

A) the site of calcium regulation differs
B) ATP energizes the sliding process
C) actin and myosin interact by the sliding filament mechanism
D) the trigger for contraction is a rise in intracellular calcium

Question 36

The oxygen-binding protein found in muscle cells is ________.

A) immunoglobin
B) hemoglobin
C) ATP
D) myoglobin

Question 37

What structure in skeletal muscle cells functions in calcium storage?

A) mitochondria
B) intermediate filament network
C) myofibrillar network
D) sarcoplasmic reticulum

Question 38

What is the functional unit of a skeletal muscle called?

A) the sarcoplasmic reticulum
B) a myofibril
C) a myofilament
D) a sarcomere

Question 39

Which of the following is the correct sequence of events for muscle contractions?

A) neurotransmitter release, muscle cell action potential, motor neuron action potential, release of calcium ions from SR, sliding of myofilaments, ATP-driven power stroke
B) motor neuron action potential, neurotransmitter release, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke, sliding of myofilaments
C) muscle cell action potential, neurotransmitter release, ATP-driven power stroke, calcium ion release from SR, sliding of myofilaments
D) neurotransmitter release, motor neuron action potential, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke

Question 40

Which of the following is a factor that affects the velocity and duration of muscle contraction?

A) load on the fiber
B) size of the muscle fibers stimulated
C) muscle length
D) number of muscle fibers stimulated

Question 41

Although all the anatomical parts of muscle work together to give it it's characteristics, which of the following proteins listed below would be most associated with the characteristics ofcontractility?

A) potassium (K+) leak channels
B) voltage gated sodium channels
C) thick (myosin) filaments
D) elastic (titin) filaments

Question 42

Which of the following statements is true?

A) Striated muscle cells are long and cylindrical with many nuclei.
B) Cardiac muscle cells are found in the heart and large blood vessels.
C) Smooth muscle cells have T tubules.
D) Cardiac muscle cells have many nuclei.

Question 43

Of the following items listed below, which is the best description for why skeletal muscle stores glycogen?

A) The glycogen is an insulating layer that helps regulate body temperature.
B) Skeletal muscle is a heavy consumer of energy.
C) Glycogen is part of muscles rigid supporting framework.
D) Glycogen provides a smooth surface for filaments to slide on.

Question 44

Although all the anatomical parts of muscle work together to give it it's characteristics, which of the following proteins listed below would be most associated with the characteristics ofextensibility?

A) potassium (K+) leak channels
B) acetylcholine receptors in the motor end plate
C) elastic (titin) filaments
D) thick (myosin) filaments

Question 45

Muscle tissue has all of the following properties except ________.

A) secretion
B) excitability
C) contractility
D) extensibility

Question 46

Which of the following describes the cells of unitary smooth muscle?

A) They are used for vision and hair raising.
B) They exhibit spontaneous action potentials.
C) They consist of muscle fibers that are structurally independent of each other.
D) They depend upon recruitment using the autonomic nervous system.

Question 47

The sliding filament model of contraction involves ________.

A) the shortening of thick filaments so that thin filaments slide past
B) actin and myosin lengthening in order to slide past each other
C) actin and myosin sliding past each other and partially overlapping
D) the Z discs sliding over the myofilaments

Question 48

Of the following muscle types, which has only one nucleus, no sarcomeres, and few gap junctions?

A) skeletal muscle
B) smooth muscle
C) cardiac muscle
D) This statement relates to all 3 types of muscle

Question 49

Although all the anatomical parts of muscle work together to give it it's characteristics, which of the following proteins listed below would be most associated with the characteristics ofexcitability?

A) actin of thin filaments
B) acetylcholine receptors in the motor end plate
C) elastic (titin) filaments
D) the Na+-K + pump

Question 50

Which of the following is true about smooth muscle?

A) Smooth muscle, in contrast to skeletal muscle, cannot synthesize or secrete any connective tissue elements.
B) Smooth muscle cannot stretch as much as skeletal muscle.
C) Smooth muscle has well-developed T tubules at the site of invagination.
D) Certain smooth muscle cells can actually divide to increase their numbers.

Question 51

What part of the sarcolemma contains acetylcholine receptors?

A) any part of the sarcolemma
B) motor end plate
C) end of the muscle fiber
D) part adjacent to another muscle cell

Question 52

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

A) acetylcholinesterase destroying the ACh
B) calcium ions returning to the terminal cisternae
C) the tropomyosin blocking the myosin once full contraction is achieved
D) the action potential stops going down the overloaded T tubules

Question 53

What is the most distinguishing characteristic of muscle tissue?

A) the ability to respond to nervous stimulation
B) its cells' in ability to reproduce by mitosis
C) the ability to transform chemical energy into mechanical energy to move the body
D) it is composed of multiple cells working together

Question 54

Oxygen starved tissues can release chemical signals into the blood that can change thediameter of nearby blood vessels delivering oxygen and nutrients to the tissues. In doing so the blood vessels will respond through vasodilation (widening of the vessel). Which muscle type is responsible for this vasodilation?

A) striated muscle
B) cardiac muscle
C) skeletal muscle
D) smooth muscle

Question 55

Smooth muscle is characterized by all of the following except ________.

A) there are noncontractile intermediate filaments that attach to dense bodies within the cell
B) there are no sarcomeres
C) there are more thick filaments than thin filaments
D) it appears to lack troponin

Question 56

Which of the following statements is most accurate?

A) The I band lengthens during isotonic contraction.
B) T tubules may be sliding during isotonic contraction.
C) Muscle tension remains relatively constant during isotonic contraction.
D) Myofilaments slide during isometric contractions.

Question 57

Hypothetically, if a muscle were stretched to the point where thick and thin filaments no longer overlapped, ________.

A) ATP consumption would increase because the sarcomere is "trying" to contract
B) maximum force production would result because the muscle has a maximum range of travel
C) cross bridge attachment would be optimum because of all the free binding sites on actin
D) no muscle tension could be generated

Question 58

An anaerobic metabolic pathway that results in the production of two net ATPs per glucose plus two pyruvic acid molecules is ________.

A) the citric acid cycle
B) the electron transport chain
C) glycolysis
D) hydrolysis

Question 59

During development embryonic cells will fuse to form muscle fibers. This will result in________.

A) the coordination of nerve signals to muscle fibers
B) interlocking of cells that can prevent the filaments from sliding
C) the striations that appear in skeletal and cardiac muscle tissues
D) multinucleated muscle fibers that can extend as long as 30 centimeters

Question 60

Muscle tone is________.

A) a state of sustained partial contraction
B) the ability of a muscle to efficiently cause skeletal movements
C) the feeling of well-being following exercise
D) the condition of athletes after intensive training

Question 61

Curare is a poisonous plant extract. Curare molecules have a chemical structure like theneurotransmitter ACh. Curare can bind to the ACh receptor site on the chemically gated ion channels in the motor end plate. Even though curare will bind to the receptor site it will notopen the ion channel and no ions will pass through. What do you think the symptoms of curare poisoning would look like?

A) Curare will only affect cardiac muscle, causing fibrillations of the heart.
B) Smooth muscles will become stimulated causing quick movement of nutrients through the digestive system.
C) Curare will only affect muscles with ACh receptors, paralyzing them.
D) Muscles will respond too quickly and cause a severe tremor.

Question 62

Myasthenia gravis is a disease that is believed to be caused by autoimmune disorder, resulting in the loss of ACh receptors at the motor end plate of muscle fibers. Which of the following islikely to be a symptom of myasthenia gravis?

A) weakness of muscle
B) coma and loss of voluntary muscle movement
C) dehydration with headache
D) seizures and uncontrollable muscle movement

Question 63

A potential benefit of recruiting slow oxidative fibers for contraction before recruiting fast oxidative and fast glycolytic fibers might be ________.

A) recruiting slow oxidative fibers early helps to tire them out first so that they won't interfere with the more powerful contractions of fast glycolytic fibers
B) because they are slower to respond, slow oxidative fibers must be stimulated first in order to contract simultaneously with the faster fibers
C) this will help to allow for fine control with delicate contractile force with a small stimulus
D) there is little to no benefit from recruiting slow oxidative fibers first and therefore it is in fact fast glycolytic fibers that will be recruited first

Question 64

Which of the following statements best illustrates the fact that skeletal muscle is voluntary muscle?

A) Skeletal muscle appears striated due to the structure of the sarcomeres.
B) Skeletal muscle is wrapped in several layers of connective tissue. The deepest layer being the endomysium.
C) Skeletal muscle fibers are innervated by somatic motor neurons.
D) The shivering reflex aids in maintaining body temperature.

Question 65

What ultimately stops muscle stimulation when the motor neuron ceases firing?

Question 66

Reduction in blood flow to a muscle fiber would have the greatest effect on ________.

A) fast oxidative fibers
B) both slow and fast oxidative
C) slow oxidative fibers
D) fast glycolytic

Question 67

Addition of more myoglobin to a muscle fiber would have the largest effect on ________.

A) fast oxidative and slow oxidative fibers
B) fast glycolytic and fast oxidative fibers
C) fast oxidative fibers only
D) fast glycolytic fibers only

Question 68

Exhaustion of glycogen storage within a muscle fiber would have the biggest effect on________.

A) slow oxidative fibers
B) fast oxidative fibers
C) both slow and fast oxidative fibers
D) fast glycolytic fibers

Question 69

When a sarcomere contracts and thin filaments move over thick filaments you would expect to see ________.

A) the A band to appear darker
B) the I bands to appear wider
C) the H zone to appear wider
D) the I bands to appear smaller

Question 70

Approximately 80% of a muscle fiber's volume are the myofibrils. This characteristic reflects muscles ability to ________.

A) generate and propagate action potential
B) produce movement through contractile force
C) produce relatively high amounts of ATP
D) store oxygen molecules that can be used in aerobic respiration

Question 71

Describe two ways in which the lack of ATP production results in rigor mortis.

Question 72

Define muscle fatigue.

Question 73

A myosin molecule in the thick filaments can be considered a protein having a quaternary structural level. Which of the following best describes this structural level?

A) Myosin molecules consist of two heavy and to light polypeptide chains.
B) Myosin is a primary component within a myofibril.
C) Myosin has an ATP binding site, actin binding site and flexible hinge region.
D) Myosin is involved in the power stroke of muscle contraction.

Question 74

Which cells help repair injured skeletal muscle fibers and allows regenerati on of dead skeletal muscle?

Question 75

Addition of more mitochondria to a muscle fiber will have the least effect on________.

A) slow oxidative fibers
B) both slow and fast oxidative fibers
C) fast glycolytic fibers
D) fast oxidative fibers

Question 76

If given the exact same amount of ATP, which of the three fiber types would be able to contract for the longest amount of time?

A) slow oxidative fibers
B) fast oxidative fibers
C) fast glycolytic fibers
D) both fast glycolytic and fast oxidative fibers

Question 77

The enzyme ________ is present in the synaptic cleft. Its activity stops the neutotransmitters stimulation.

Question 78

The end of the muscle that is attached to the part of the body in motion when a muscle contracts is called the ________.

Question 79

If a muscle fiber were to suddenly and permanently stop producing ATP the fiber would no longer be able to actively transport calcium out of the cytoplasm (sarcoplasm) and theintracellular calcium concentration would rise. Which of the following would you expect to ha ppen?

A) Myosin would be able to bind to the exposed binding sites on thin filaments but it would not be able to detach.
B) Calcium would be transported to the sarcoplasmic reticulum therefore contractions would cease.
C) No change would occur in a muscle that was relaxed to begin with.
D) The fiber would twitch uncontrollably due to excessive calcium bound to troponin.

Question 80

Only________ muscle cells are multinucleated.