quiz 9 a&p
The thicker filaments are the ________ filaments. A) A band B) I band C) Z discs D) Myosin
Myosin
Of the following muscle types, which has the longest muscle cells and has obvious stripes called striations? A. skeletal muscle B. cardiac muscle C. visceral smooth muscle D. multiunit smooth muscle
skeletal muscle
Addition of more mitochondria to a muscle fiber will have the greatest effect on ________. A. fast glycolytic fibers B. fast oxidative fibers C. both slow and fast oxidative fibers D. slow oxidative fibers
slow oxidative fibers
The mechanism of contraction in smooth muscle is different from skeletal muscle in that ________. A. ATP energizes the sliding process B. actin and myosin interact by the sliding filament mechanism C. the site of calcium binding site differs D. the trigger for contraction is a rise in intracellular calcium
the site of calcium binding site differs
Determined by alternating motor units of a muscle organ even when the muscle is at rest. A) Muscle tone B) Isotonic contraction C) Multiple motor unit summation D) Tetanus E) Isometric contraction
A) Muscle tone
The myosin filaments are located in the ________. A) A band B) I band C) Z discs D) Myosin
A band
Both actin and myosin are found in the _ A) A band B) I band C) Z discs D) Myosin
A band
A neurotransmitter released at motor end plates by the axon terminals. A) Acetylcholine B) Acetylcholinesterase C) Sodium ions D) Calcium ions E) Neuromuscular junction
A) Acetylcholine
Have very fast-acting myosin ATPases and depend upon aerobic metabolism during contraction. A) Fast (oxidative), fatigue-resistant fibers B) Fast (glycolytic), fatigable fibers C) Slow (oxidative), fatigue-resistant fibers
A) Fast (oxidative), fatigue-resistant fibers
Troponin, a major protein in thin filaments, is a globular protein with three polypeptide subunits. Which of the following is NOT a function of the troponin? A. One subunit binds to potassium ions. B. One subunit binds tropomyosin and helps position it on actin. C. One subunit binds to calcium ions. D. One subunit attaches troponin to actin.
A. One subunit binds to potassium ions.
25 Meter Swim A) Anaerobic Pathway B) Direct Phosphorylation C) Aerobic Pathway
A. Anaerobic pathway
A potential benefit of recruiting slow oxidative fibers for contraction before recruiting fast oxidative and fast glycolytic fibers might be ________. A. to allow for fine control with delicate contractile force with a small stimulus B. 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 C. because they are slower to respond, slow oxidative fibers must be stimulated first in order to contract simultaneously with the faster fibers
A. to allow for fine control with delicate contractile force with a small stimulus
Breaks down ACh into its building blocks, rendering it inactive. A) Acetylcholine B) Acetylcholinesterase C) Sodium ions D) Calcium ions E) Neuromuscular junction
B) Acetylcholinesterase
Contain abundant amounts of glycogen. A) Fast (oxidative), fatigue-resistant fibers B) Fast (glycolytic), fatigable fibers C) Slow (oxidative), fatigue-resistant fibers
B) Fast (glycolytic), fatigable fibers
When the muscle tension developed overcomes the load and muscle shortening occurs. A) Muscle tone B) Isotonic contraction C) Multiple motor unit summation D) Tetanus E) Isometric contraction
B) Isotonic contraction
Reduction in blood flow to a muscle fiber would have the greatest effect on ________. A. fast glycolytic B. slow oxidative fibers C. both slow and fast oxidative D. fast oxidative fibers
B. slow oxidative fibers
weight lifting A) Anaerobic Pathway B) Direct Phosphorylation C) Aerobic Pathway
B. Direct phosphorylatin
Which of the following statements best illustrates the fact that skeletal muscle is voluntary muscle? A. Skeletal muscle is wrapped in several layers of connective tissue. The deepest layer being the endomysium. B. Skeletal muscle fibers are innervated by somatic motor neurons. C. The shivering reflex aids in maintaining body temperature. D. Skeletal muscle appears striated due to the structure of the sarcomeres.
B. Skeletal muscle fibers are innervated by somatic motor neurons.
How a smooth increase in muscle force is produced. A) Muscle tone B) Isotonic contraction C) Multiple motor unit summation D) Tetanus E) Isometric contraction
C) Multiple motor unit summation
A relatively high percentage are found in successful marathon runners. A) Fast (oxidative), fatigue-resistant fibers B) Fast (glycolytic), fatigable fibers C) Slow (oxidative), fatigue-resistant fibers
C) Slow (oxidative), fatigue-resistant fibers
Abundant in muscles used to maintain posture. A) Fast (oxidative), fatigue-resistant fibers B) Fast (glycolytic), fatigable fibers C) Slow (oxidative), fatigue-resistant fibers
C) Slow (oxidative), fatigue-resistant fibers
Depend on oxygen delivery and aerobic mechanisms. A) Fast (oxidative), fatigue-resistant fibers B) Fast (glycolytic), fatigable fibers C) Slow (oxidative), fatigue-resistant fibers
C) Slow (oxidative), fatigue-resistant fibers
Red fibers, the smallest of the fiber types. A) Fast (oxidative), fatigue-resistant fibers B) Fast (glycolytic), fatigable fibers C) Slow (oxidative), fatigue-resistant fibers
C) Slow (oxidative), fatigue-resistant fibers
It diffuses across the cell membrane resulting in depolarization. A) Acetylcholine B) Acetylcholinesterase C) Sodium ions D) Calcium ions E) Neuromuscular junction
C) Sodium ions
The sliding filament model of contraction involves ________. A. the shortening of thick filaments so that thin filaments slide past B. the Z discs sliding over the myofilaments C. actin and myosin sliding past each other and partially overlapping D. actin and myosin lengthening in order to slide past each other
C. actin and myosin sliding past each other and partially overlapping
The strongest muscle contractions are normally achieved by ________. A. increasing stimulus above the threshold B. recruiting small and medium muscle fibers C. increasing the stimulation up to the maximal stimulus D. increasing stimulus above the treppe stimulus
C. increasing the stimulation up to the maximal stimulus
Rigor mortis occurs because ________. A. proteins are beginning to break down, thus preventing a flow of calcium ions B. sodium ions leak into the muscle causing continued contractions C. no ATP is available to release attached actin and myosin molecules D. the cells are dead
C. no ATP is available to release attached actin and myosin molecules
Marathons A) Anaerobic Pathway B) Direct Phosphorylation C) Aerobic Pathway
C. Aerobic pathway
Curare is a poisonous plant extract. Curare molecules have a chemical structure like the neurotransmitter 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 not open 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. Muscles will respond too quickly and cause a severe tremor. D. Curare will only affect muscles with ACh receptors, paralyzing them.
Curare will only affect muscles with ACh receptors, paralyzing them.
Activates synaptic vesicles in axon terminals to fuse with plasma membrane of axon terminal. A) Acetylcholine B) Acetylcholinesterase C) Sodium ions D) Calcium ions E) Neuromuscular junction
D) Calcium ions
The final chemical messenger and "trigger" for muscle contraction. It binds to troponin. A) Acetylcholine B) Acetylcholinesterase C) Sodium ions D) Calcium ions E) Neuromuscular junction
D) Calcium ions
Continued sustained smooth contraction due to rapid stimulation. A) Muscle tone B) Isotonic contraction C) Multiple motor unit summation D) Tetanus E) Isometric contraction
D) Tetanus
When muscle tension develops but the load is not moved. A) Muscle tone B) Isotonic contraction C) Multiple motor unit summation D) Tetanus E) Isometric contraction
E) Isometric contraction
Where the axon of a motor neuron connects with the muscle fibers. A) Acetylcholine B) Acetylcholinesterase C) Sodium ions D) Calcium ions E) Neuromuscular junction
E) Neuromuscular junction
The ________ contains only the actin filaments A) A band B) I band C) Z discs D) Myosin
I band
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.
Striated muscle cells are long and cylindrical with many nuclei.
Of the following items listed below, which is the best description for why skeletal muscle stores glycogen? A. Skeletal muscle is a heavy consumer of energy. B. Glycogen is part of the muscles rigid supporting framework. C. The glycogen is an insulating layer that helps regulate body temperature. D. Glycogen provides a smooth surface for filaments to slide on.
Skeletal muscle is a heavy consumer of energy.
The 100-meter dash is a quick and short run requiring explosive speed. On completion of the dash, the runners will continue to breathe hard for several seconds to minutes even though they are no longer running. Which of the following is the best explanation for why this is so? A. The runners' fast oxidative muscles are so slow to utilize oxygen, they only begin aerobic respiration by the time the run has finished. B. Slow oxidative fibers are recruited last and have only started to work at completion of the run. C. Since the exercise was mostly aerobic exercise, the runners' bodies have not yet realized the run is over. D. The runners' use of stored oxygen, glucose, and creatine phosphate is being replenished and this requires a prolonged increase of oxygen intake.
The runners' use of stored oxygen, glucose, and creatine phosphate is being replenished and this requires a prolonged increase of oxygen intake
Which of the following describes the cells of unitary smooth muscle? A. They exhibit spontaneous action potentials. B. They consist of muscle fibers that are structurally independent of each other. C. They depend upon recruitment using the autonomic nervous system. D. They are used for vision and hair raising.
They exhibit spontaneous action potentials.
What is the role of tropomyosin in skeletal muscles? A. Tropomyosin is the receptor for the motor neuron neurotransmitter. B. Tropomyosin is the chemical that activates the myosin heads. C. Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules. D. Tropomyosin serves as a contraction inhibitor by blocking the actin binding sites on the myosin molecules.
Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules.
A sarcomere is the distance between two A) A band B) I band C) Z discs D) Myosin
Z discs
Most skeletal muscles contain ________. A. a mixture of fiber types B. muscle fibers of the same type C. a predominance of slow oxidative fibers D. a predominance of fast oxidative fibers
a mixture of fiber types
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 of excitability? A. the Na+-K+ pump B. actin of thin filaments C. acetylcholine receptors in the motor end plate D. elastic (titin) filaments
acetylcholine receptors in the motor end plate
After nervous stimulation stops, what prevents ACh in the synaptic cleft from continuing to stimulate contraction? A. calcium ions returning to the terminal cisternae B. the action potential stops going down the overloaded T tubules C. the tropomyosin blocking the myosin once full contraction is achieved D. acetylcholinesterase breaks apart the ACh
acetylcholinesterase breaks apart the ACh
During muscle contraction, myosin cross bridges attach to which active sites? A. Z discs B. thick filaments C. myosin filaments D. actin filaments
actin filaments
Which of the following is true about smooth muscle? A. Smooth muscle has well-developed T tubules at the site of invagination. B. Smooth muscle cannot stretch as much as skeletal muscle. C. Smooth muscle, in contrast to skeletal muscle, cannot synthesize or secrete any connective tissue elements. D. Certain smooth muscle cells can actually divide to increase their numbers.
certain smooth muscle cells can actually divide to increase their numbers
In an isotonic contraction, the muscle ________. A. changes in length and moves the "load" B. does not change in length but increases tension C. never converts pyruvate to lactate D. rapidly resynthesizes creatine phosphate and ATP
changes in length and moves the load
The ability of muscle to shorten forcibly when adequately stimulated is known as ________, and sets muscle apart from other tissue types. A. contractility B. elasticity C. excitability D. extensibility
contractility
Although all the anatomical parts of muscle work together to give it its characteristics, which of the following proteins listed below would be most associated with the characteristics of extensibility? A. thick (myosin) filaments B. elastic (titin) filaments C. potassium (K+) leak channels D. acetylcholine receptors in the motor end plate
elastic (titin) filaments
Which of the following surrounds an individual muscle cell? A. epimysium B. perimysium C. fascicle D. endomysium
endomysium
During isometric contraction, the energy used appears as movement. t or f
false
Muscle contraction will always promote movement of body parts regardless of how they are attached. t or f
false
Once a motor neuron has fired, all the muscle fibers in a muscle contract. t or f
false
Exhaustion of glycogen storage within a muscle fiber would have the biggest effect on ________. A. slow oxidative fibers B. fast glycolytic fibers C. both slow and fast oxidative fibers D. fast oxidative fibers
fast glycolytic fibers
Addition of more myoglobin to a muscle fiber would have the largest effect on ________. A. fast glycolytic and fast oxidative fibers B. fast oxidative fibers only C. fast oxidative and slow oxidative fibers D. fast glycolytic fibers only
fast oxidative and slow oxidative fibers
Which of the following is a factor that affects the velocity and duration of muscle contraction? A. muscle length B. number of muscle fibers stimulated C. size of the muscle fibers stimulated D. load on the fiber
load on the fiber
What part of the sarcolemma contains acetylcholine receptors? A. part adjacent to another muscle cell B. motor end plate C. end of the muscle fiber D. any part of the sarcolemma
motor end plate
Which of the following is the correct sequence of events for muscle contractions? A. muscle cell action potential, neurotransmitter release, ATP-driven power stroke, calcium ion release from SR, sliding of myofilaments 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. neurotransmitter release, motor neuron action potential, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke D. neurotransmitter release, muscle cell action potential, motor neuron action potential, release of calcium ions from SR, sliding of myofilaments, ATP-driven power stroke
motor neuron action potential, neurotransmitter release, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke, sliding of myofilaments
Which of the following would be recruited later in muscle stimulation when contractile strength increases? A. motor units with the longest muscle fibers B. large motor units with small, highly excitable neurons C. many small motor units with the ability to stimulate other motor units D. motor units with larger, less excitable neurons
motor units with larger, less excitable neurons
the contractile units of skeletal muscles are ________. A. microtubules B. myofibrils C. mitochondria D. T tubules
myofibrils
The oxygen-binding protein found in muscle cells is ________. A. ATP B. myoglobin C. hemoglobin D. immunoglobin
myoglobin
he oxygen-binding protein found in muscle cells is ________. A. ATP B. hemoglobin C. immunoglobin D. myoglobin
myoglobin
Hypothetically, if a muscle were stretched to the point where thick and thin filaments no longer overlapped, ________. A. cross bridge attachment would be optimum because of all the free binding sites on actin B. maximum force production would result because the muscle has a maximum range of travel C. ATP consumption would increase because the sarcomere is "trying" to contract D. no muscle tension could be generated
no muscle tension could be generated
Approximately 80% of a muscle fiber's volume are the myofibrils. This characteristic reflects muscles ability to ________. A. produce movement through contractile force B. store oxygen molecules that can be used in aerobic respiration C. produce relatively high amounts of ATP D. generate and propagate action potential
produce movement through contractile force
What is the primary function of wave summation? A. prevent muscle relaxation B. increase muscle tension C. produce smooth, continuous muscle contraction D. prevent muscle fatigue
produce smooth, continuous muscle contraction
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. A. relaxation B. refractory C. contraction D. latent
refractory
When a muscle is unable to respond to stimuli temporarily, it is in which of the following periods? A. fatigue period B. refractory period C. relaxation period D. latent period
refractory period
Which of the following is the correct order for the phases of a muscle twitch? A. relaxation, contraction, latent B. latent, contraction, relaxation C. contraction, relaxation, latent D. latent, relaxation, contraction
relaxation, contraction, latent
What structure in skeletal muscle cells functions in calcium storage? A. intermediate filament network B. mitochondria C. sarcoplasmic reticulum D. myofibrillar network
sarcoplasmic reticulum
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. both fast glycolytic and fast oxidative fibers B. fast oxidative fibers C. slow oxidative fibers D. fast glycolytic fibers
slow oxidative fibers
Which muscle cells have the greatest ability to regenerate? A. smooth B. no muscle can regenerate C. cardiac D. skeletal
smooth
Oxygen starved tissues can release chemical signals into the blood that can change the diameter 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. smooth muscle D. skeletal muscle
smooth muscle
Myoglobin ________. A. breaks down glycogen B. stores oxygen in muscle cells C. produces the end plate potential D. is a protein involved in the direct phosphorylation of ADP
stores oxygen in muscle cells
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
storing energy that will be transferred to ADP to resynthesize ATP
What is the most distinguishing characteristic of muscle tissue? A. the ability to respond to nervous stimulation B. It is composed of multiple cells working together. C. its cells' inability to reproduce by mitosis D. the ability to transform chemical energy into mechanical energy to move the body
the ability to transform chemical energy into mechanical energy to move the body
What does excess postexercise oxygen consumption represent? A. the amount of oxygen taken into the body immediately after the exertion B. the amount of oxygen equal to the oxygen already used C. the difference between the amount of oxygen needed for totally aerobic muscle activity and the amount actually used D. amount of oxygen needed for aerobic activity to accomplish the same amount of work
the difference between the amount of oxygen needed for totally aerobic muscle activity and the amount actually used
When a sarcomere contracts and thin filaments move over thick filaments you would expect to see ________. A. the H zone to appear wider B. the I bands to appear smaller C. the I bands to appear wider D. the A band to appear darker
the i bands to appear smaller
Smooth muscle is characterized by all of the following EXCEPT ________. A. there are no sarcomeres B. it appears to lack troponin C. there are noncontractile intermediate filaments that attach to dense bodies within the cell D. there are more thick filaments than thin filaments
there are more thick filaments than thin filaments
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 of contractility? A. potassium (K+) leak channels B. thick (myosin) filaments C. elastic (titin) filaments D. voltage gated sodium channels
thick (myosin) filaments
A contraction in which the muscle does not shorten but its tension increases is called isometric contraction. t or f
true
A skeletal muscle contracts with varying force and length of time in response to the body's needs at the time. t or f
true
Although there are no sarcomeres, smooth muscle still possesses thick and thin filaments. True False
true
Cardiac muscle has a limited regenerative capacity. True False
true
Cells of unitary smooth muscle are found in the longitudinal and circular muscle layers of the intestine. True False
true
Excitability is the ability of a cell to receive and respond to stimulus by changing its membrane potential. t or f
true
Muscle cells store more creatine phosphate than ATP resulting in the muscle having a reserve source of energy. t or f
true
Muscle tone is the small amount of tautness or tension in the muscle due to weak, involuntary contractions of its motor units. True False
true
Peristalsis is characteristic of smooth muscle. True False
true
Smooth muscles relax when intracellular Ca2+ levels drop but may not cease contractions. t or f
true
The effect of a neurotransmitter on the muscle cell membrane is to modify its ion permeability properties temporarily. True False
true
The thin filaments (actin) contain a polypeptide subunit G actin that bears active sites for myosin attachment. True False
true
When a muscle fiber contracts, the I bands diminish in size, the H zones disappear, and the A bands do not diminish in length. t or f
true
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 is likely to be a symptom of myasthenia gravis? A. coma and loss of voluntary muscle movement B. weakness of muscle C. dehydration with headache D. seizures and uncontrollable muscle movement
weakness of muscle
