FINAL A&P Chapter 9 & 11
C
In which phase in the figure would the net movement of Ca2+ into the sarcoplasmic reticulum (SR) be greatest? A)A B)B C)C
What changes occur to voltage-gated Na+ and K+ channels at the peak of depolarization? A)Inactivation gates of voltage-gated Na+ channels close, while inactivation gates of voltage-gated K+ channels open. B)Activation gates of voltage-gated Na+ channels close, while inactivation gates of voltage-gated K+ channels open. C)Activation gates of voltage-gated Na+ channels close, while activation gates of voltage-gated K+ channels open. D)Inactivation gates of voltage-gated Na+ channels close, while activation gates of voltage-gated K+ channels open.
Inactivation gates of voltage-gated Na+ channels close, while activation gates of voltage-gated K+ channels open.
Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. When muscle tension develops but the load is not moved. A)Muscle tone B)Multiple motor unit summation C)Isometric contraction D)Isotonic contraction E)Tetanus
Isometric contraction
Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. When the muscle tension developed overcomes the load and muscle shortening occurs. A)Muscle tone B)Multiple motor unit summation C)Isometric contraction D)Isotonic contraction E)Tetanus
Isotonic contraction
The membranes of neurons at rest are very permeable to _____ but only slightly permeable to _____. A)K+; Na+ B)K+; Cl- C)Na+; K+ D)Na+; Cl-
K+; Na+
Which of the following processes produces 36 ATP? A)hydrolysis of creatine phosphate B)Krebs cycle and oxidative phosphorylation C)glycolysis
Krebs cycle and oxidative phosphorylation
Drag the terms on the left to the appropriate blanks on the right to complete the sentences. The stimulus above which no stronger contraction can be elicited, because all motor units are firing in the muscle. A)Muscle tone B)Tetanus C)Multiple motor unit summation D)Maximal stimulus E)Wave summation
Maximal stimulus
What is the role of calcium in the cross bridge cycle? A)Calcium binds to myosin, causing the myosin head to release from the actin myofilament. B)Calcium binds to troponin, exposing the active site on troponin. C)Calcium binds to active sites on actin, forming the cross bridge. D)Calcium binds to troponin, altering its shape.
Calcium binds to troponin, altering its shape.
Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. Words can be used more than once. Activates synaptic vesicles in axon terminals to fuse with plasma membrane of axon terminal. A)Acetylocholine B)Neuromuscular junction C)Sodium ions D)Calcium ions E)Acetylcholinesterase
Calcium ions
Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. Words can be used more than once. The final chemical messenger and "trigger" for muscle contraction. It binds to troponin. A)Acetylocholine B)Neuromuscular junction C)Sodium ions D)Calcium ions E)Acetylcholinesterase
Calcium ions
Calcium ions couple excitation of a skeletal muscle fiber to contraction of the fiber. Where are calcium ions stored within the fiber? A)Calcium ions are stored in the transverse tubules. B)Calcium ions are stored in the nuclei. C)Calcium ions are stored in the mitochondria. D)Calcium ions are stored in the sarcoplasmic reticulum.
Calcium ions are stored in the sarcoplasmic reticulum.
What specific event triggers the uncovering of the myosin binding site on actin? A)Calcium release channels open in the sarcoplasmic reticulum, and calcium levels rise in the sarcoplasm. B)Calcium ions bind to troponin and change its shape. C)Sodium ions bind to troponin and change its shape. D)Calcium ions bind to tropomyosin and change its shape.
Calcium ions bind to troponin and change its shape.
Which of the following is most directly responsible for the coupling of excitation to contraction of skeletal muscle fibers? A)Calcium ions. B)Acetylcholine. C)Action potentials. D)Sodium ions.
Calcium ions.
Excitation of the sarcolemma is coupled or linked to the contraction of a skeletal muscle fiber. What specific event initiates the contraction? A)Calcium release from the sarcoplasmic reticulum initiates the contraction. B)Action potentials propagate into the interior of the skeletal muscle fiber. C)Sodium release from the sarcoplasmic reticulum initiates the contraction. D)Voltage-sensitive proteins change shape.
Calcium release from the sarcoplasmic reticulum initiates the contraction.
When a neurotransmitter like acetylcholine is acting in an excitatory manner which of the following is likely a result of the acetylcholine acting on the post synaptic cell? A)Chemically gated sodium channels will be closed. B)Chemically gated potassium channels will open. C)Chemically gated sodium channels will open. D)Chemically gated chloride channels will open.
Chemically gated sodium channels will open.
What type of conduction takes place in unmyelinated axons? A)Electrical conduction B)Saltatory conduction C)Continuous conduction D)Synaptic transmission
Continuous conduction
Drag the terms on the left to the appropriate blanks on the right to complete the sentences. Terms may be used more than once. Different types of sensory input can have the same ultimate effect. A)Diverging circuit B)Reverberating circuit C)Parallel after-discharge circuit D)Converging circuit
Converging circuit
When does cross bridge cycling end? A)Cross bridge cycling ends when calcium ions are passively transported back into the sarcoplasmic reticulum. B)Cross bridge cycling ends when ATP binds to the myosin head. C)Cross bridge cycling ends when calcium release channels in the sarcoplasmic reticulum open. D)Cross bridge cycling ends when sufficient calcium has been actively transported back into the sarcoplasmic reticulum to allow calcium to unbind from troponin.
Cross bridge cycling ends when sufficient calcium has been actively transported back into the sarcoplasmic reticulum to allow calcium to unbind from troponin.
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)Muscles will respond too quickly and cause a severe tremor. B)Curare will only affect cardiac muscle, causing fibrillations of the heart. C)Curare will only affect muscles with ACh receptors, paralyzing them. D)Smooth muscles will become stimulated causing quick movement of nutrients through the digestive system.
Curare will only affect muscles with ACh receptors, paralyzing them.
A
Destruction of which of the neuroglial cell types leads to the disease multiple sclerosis (MS)? A)A B)B C)C D)D E)F
The effect of acetylcholine can be stimulating or inhibiting. Which of the following gives the best explanation for why this is so? A)Acetylcholine has many different forms. B)Postsynaptic cells have a dynamic and changing metabolism and respond differently at different times. C)Different post synaptic cells will have different receptors. D)Acetylcholine has a "dose effect". Larger doses are stimulating while small doses inhibit.
Different post synaptic cells will have different receptors.
motor unit
Each neuron shown in this figure innervates a group of muscle fibers. What is the term for a group of muscle fibers innervated by a single neuron? A)sarcomere B)fascicle C)motor unit D)neuromuscular junction
Excitation-contraction coupling is a series of events that occur after the events of the neuromuscular junction have transpired. The term excitation refers to which step in the process? A)Excitation refers to the propagation of action potentials along the axon of a motor neuron. B)Excitation refers to the release of calcium ions from the sarcoplasmic reticulum. C)Excitation, in this case, refers to the propagation of action potentials along the sarcolemma. D)Excitation refers to the shape change that occurs in voltage-sensitive proteins in the sarcolemma.
Excitation, in this case, refers to the propagation of action potentials along the sarcolemma.
recruitment
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 __________. A)tetanus B)excitation-contraction coupling C)recruitment D)wave summation
What is the value for the resting membrane potential for most neurons? A)+30 mV B)-90 mV C)-70 mV
-70 mV
The cross bridge cycle is a series of molecular events that occur after excitation of the sarcolemma. What is a cross bridge? A)Calcium bound to troponin B)A myosin head bound to actin C)ATP bound to a myosin head D)Troponin bound to tropomyosin
A myosin head bound to actin
Which of the following is false or incorrect? A)An inhibitory postsynaptic potential occurs if the inhibitory effect is greater than the excitatory, causing hyperpolarization of the membrane. B)A nerve impulse occurs if the excitatory and inhibitory effects are equal. C)An excitatory postsynaptic potential occurs if the excitatory effect is greater than the inhibitory effect but less than threshold.
A nerve impulse occurs if the excitatory and inhibitory effects are equal.
Which of the following is true of axons? A)A neuron can have only one axon, but the axon may have occasional branches along its length. B)Neurons can have multiple axons but only one dendrite. C)Smaller (thinner) axons are more likely to bear myelin sheaths than larger (thicker) axons. D)Axons use chemically gated ion channels to generate graded potentials.
A neuron can have only one axon, but the axon may have occasional branches along its length.
A triad is composed of a T-tubule and two adjacent terminal cisternae of the sarcoplasmic reticulum. How are these components connected? A)Myosin cross-bridge binding sites. B)Potassium leak channels. C)Voltage-gated sodium channels. D)A series of proteins that control calcium release.
A series of proteins that control calcium release.
Which of the following will occur when an excitatory postsynaptic potential (EPSP) is being generated on the dendritic membrane? A)Sodium gates will open first, then close as potassium gates open. B)Specific sodium gates will open. C)Specific potassium gates will open. D)A single type of channel will open, permitting simultaneous flow of sodium and potassium.
A single type of channel will open, permitting simultaneous flow of sodium and potassium.
Which step precedes all of the other listed steps? A)Na+ rushes into the cell. B)The sarcoplasmic reticulum is activated. C)ACh is released by the motor neuron. D)An action potential starts on the sarcolemma.
ACh is released by the motor neuron.
Which event causes cross bridge detachment? A)release of calcium from troponin B)release of ADP and inorganic phosphate from the myosin head C)ATP binding to the myosin head D)nervous input ends
ATP binding to the myosin head
After a power stroke, the myosin head must detach from actin before another power stroke can occur. What causes cross bridge detachment? A)ADP and inorganic phosphate are bound to the myosin head. B)Calcium ions bind to troponin. C)ATP binds to the myosin head. D)Acetylcholine binds to receptors in the junctional folds of the sarcolemma.
ATP binds to the myosin head.
Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. Words can be used more than once. A neurotransmitter released at motor end plates by the axon terminals. A)Acetylocholine B)Neuromuscular junction C)Sodium ions D)Calcium ions E)Acetylcholinesterase
Acetylcholine
Action potential propagation in a skeletal muscle fiber ceases when acetylcholine is removed from the synaptic cleft. Which of the following mechanisms ensures a rapid and efficient removal of acetylcholine? A)Acetylcholine is transported back into the axon terminal by a reuptake mechanism. B)Acetylcholine is transported into the postsynaptic neuron by receptor-mediated endocytosis. C)Acetylcholine is degraded by acetylcholinesterase. D)Acetylcholine diffuses away from the cleft.
Acetylcholine is degraded by acetylcholinesterase.
The neuromuscular junction is a well-studied example of a chemical synapse. Which of the following statements describes a critical event that occurs at the neuromuscular junction? A)Acetylcholine is released and moves across the synaptic cleft bound to a transport protein. B)When the action potential reaches the end of the axon terminal, voltage-gated sodium channels open and sodium ions diffuse into the terminal. C)Acetylcholine is released by axon terminals of the motor neuron. D)Acetylcholine binds to its receptor in the junctional folds of the sarcolemma. Its receptor is linked to a G protein.
Acetylcholine is released by axon terminals of the motor neuron.
Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. Words can be used more than once. Breaks down ACh into its building blocks, rendering it inactive. A)Acetylocholine B)Neuromuscular junction C)Sodium ions D)Calcium ions E)Acetylcholinesterase
Acetylocholinesterase
Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. Marathons A)Aerobic pathway B)Anaerobic pathway C)Direct phosphorylation
Aerobic pathway
How/when does the myosin head cock back to store energy for the next cycle? A)when ADP is released from the myosin head B)The sliding of the actin myofilament during the power stroke re-cocks myosin heads that have previously delivered their power stroke. C)The power stroke cocks the myosin head. D)After the myosin head detaches, energy from ATP hydrolysis is used to re-cock the myosin head.
After the myosin head detaches, energy from ATP hydrolysis is used to re-cock the myosin head.
Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. 25 meter swim A)Aerobic pathway B)Anaerobic pathway C)Direct phosphorylation
Anaerobic pathway
Which of the following is NOT a normal function of muscle tissue? A)producing movement B)maintaining posture C)generating heat D)secreting hormones E)stabilizing joints
secreting hormones
Muscle tissue has all of the following properties except ________. A)secretion B)extensibility C)contractility D)excitability
secretion
Which type of muscle requires voluntary nervous stimulation for activation? A)visceral B)cardiac C)smooth D)skeletal
skeletal
Which of the following are correctly paired? A)smooth muscle; striated B)cardiac muscle; nonstriated C)skeletal muscle; voluntary control D)cardiac muscle; voluntary control
skeletal muscle; voluntary control
Hyperpolarization results from __________. A)slow closing of voltage-gated K+ channels B)slow closing of voltage-gated Na+ channels C)fast closing of voltage-gated K+ channels
slow closing of voltage-gated K+ channels
Which muscle cells have the greatest ability to regenerate? A)smooth B)skeletal C)no muscle can regenerate D)cardiac
smooth
What division of the nervous system is most specifically responsible for voluntary motor control? A)parasympathetic nervous system B)sympathetic nervous system C)central nervous system D)somatic nervous system
somatic nervous system
Myoglobin ________. A)is a protein involved in the direct phosphorylation of ADP B)breaks down glycogen C)stores oxygen in muscle cells D)produces the end plate potential
stores oxygen in muscle cells
Creatine phosphate functions in the muscle cell by ________. A)storing energy that will be transferred to ADP to resynthesize ATP B)forming a temporary chemical compound with myosin C)forming a chemical compound with actin D)inducing a conformational change in the myofilaments
storing energy that will be transferred to ADP to resynthesize ATP
The small space between the sending neuron and the receiving neuron is the A)neurotransmitter. B)calcium channel. C)vesicle. D)synaptic terminal. E)synaptic cleft.
synaptic cleft.
What is the most distinguishing characteristic of muscle tissue? A)It is composed of multiple cells working together. B)its cells' inability to reproduce by mitosis C)the ability to respond to nervous stimulation 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
The force of a muscle contraction is NOT affected by __________. A)the size of the muscle fibers stimulated B)the frequency of the stimulation C)the amount of ATP stored in the muscle cells D)the number of muscle fibers stimulated E)the degree of muscle stretch
the amount of ATP stored in the muscle cells
Which criterion is used to functionally classify neurons? A)whether the neurons are found within the CNS or the PNS B)whether the nerve fibers are myelinated or unmyelinated C)the direction in which the nerve impulse travels relative to the central nervous system D)the number of processes extending from the cell body neuron
the direction in which the nerve impulse travels relative to the central nervous system
An action potential in one segment of axon causes adjacent sections of axon membrane to reach threshold through what mechanism? A)neurotransmitters causing chemically gated channels to open B)the generation of local currents C)Na+ ions diffusing across the membrane through leakage channels D)K+ ions diffusing through voltage-gated channels
the generation of local currents
If a motor neuron in the body were stimulated by an electrode placed about midpoint along the length of the axon ________. A)muscle contraction would occur B)the impulse would move to the axon terminal only C)the impulse would spread bidirectionally D)the impulse would move to the axon terminal only, and the muscle contraction would occur
the impulse would spread bidirectionally
A toxin released by certain bacteria can block the release of neurotransmitters into a neuromuscular synapse. What would result from such a block? A)the loss of ability to contract the muscle B)The muscle would become permanently contracted. C)The muscle would remain fixed at the length it was when the toxin contacted it.
the loss of ability to contract the muscle
Saltatory conduction is made possible by ________. A)diphasic impulses B)the myelin sheath C)erratic transmission of nerve impulses D)large nerve fibers
the myelin sheath
The repolarization phase of an action potential results from __________. A)the opening of voltage-gated Na+ channels B)the opening of voltage-gated K+ channels C)the closing of voltage-gated K+ channels D)the closing of voltage-gated Na+ channels
the opening of voltage-gated K+ channels
If a signal from a sending neuron makes the receiving neuron more negative inside, A)the sending neuron becomes more positive inside. B)the receiving neuron is more likely to generate an action potential. C)the receiving neuron immediately generates an action potential. D)the sending neuron becomes more negative inside. E)the receiving neuron is less likely to generate an action potential.
the receiving neuron is less likely to generate an action potential.
The contractile, or functional, unit of a muscle fiber is __________. A)the sarcomere B)the elastic filament C)troponin D)the myofilament
the sarcomere
Which muscle cell structure stores calcium ions that are used to trigger the contraction? A)the sarcoplasmic reticulum B)the myofibril C)glycosome D)the sarcolemma
the sarcoplasmic reticulum
The mechanism of contraction in smooth muscle is different from skeletal muscle in that ________. A)the trigger for contraction is a rise in intracellular calcium B)actin and myosin interact by the sliding filament mechanism C)the site of calcium regulation differs D)ATP energizes the sliding process
the site of calcium regulation differs
Which of the following allows us to consciously control our skeletal muscles? A)the afferent division of the nervous system B)the sympathetic division of the autonomic nervous system C)the parasympathetic division of the autonomic nervous system D)the somatic nervous system
the somatic nervous system
As you start working out, you notice that your heart rate and breathing rate start to increase. Which division of your nervous system is generating this response? Be as specific as possible. A)the parasympathetic division of the autonomic nervous system B)the afferent division of the nervous system C)the somatic nervous system D)the sympathetic division of the autonomic nervous system
the sympathetic division of the autonomic nervous system
When calcium ions enter the synaptic terminal, A)they cause an action potential in the sending neuron. B)neurotransmitter molecules are quickly removed from the synaptic cleft. C)they cause vesicles containing neurotransmitter molecules to fuse to the plasma membrane of the sending neuron. D)the inside of the receiving neuron becomes more positive. E)the inside of the receiving neuron becomes more negative.
they cause vesicles containing neurotransmitter molecules to fuse to the plasma membrane of the sending neuron.
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)thick (myosin) filaments B)elastic (titin) filaments C)potassium (K+) leak channels D)voltage gated sodium channels
thick (myosin) filaments
What is name given to the regularly spaced infoldings of the sarcolemma? A)terminal cisternae B)motor endplates C)transverse or T tubules D)sarcoplasmic reticulum
transverse or T tubules
The interaction between which protein and ion initiates muscle coupling? A)troponin; sodium ions B)myosin; sodium ions C)tropomyosin; calcium ions D)troponin; calcium ions
troponin; calcium ions
T/F A resting potential is caused by a difference in the concentration of certain ions inside and outside the cell.
true
T/F A stimulus traveling toward a synapse appears to open calcium ion channels at the presynaptic end, which in turn promotes fusion of synaptic vesicles to the axonal membrane.
true
T/F Although there are no sarcomeres, smooth muscle still possesses thick and thin filaments.
true
T/F 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
T/F Bundles of axons in the central nervous system are called tracts.
true
T/F Cardiac muscle has a limited regenerative capacity.
true
T/F Cell bodies of sensory neurons may be located in ganglia lying outside the central nervous system.
true
T/F During depolarization, the inside of the neuron's membrane becomes less negative.
true
T/F Efferent nerve fibers may be described as motor nerve fibers.
true
T/F Enkephalins and endorphins are peptides that act like morphine.
true
T/F Excitability is the ability of a cell to receive and respond to stimulus by changing its membrane potential.
true
T/F If the neuron membrane becomes more permeable to Na+, Na+ will transport across the membrane, causing the cell to depolarize.
true
T/F In myelinated axons the voltage-regulated sodium channels are concentrated at the nodes of Ranvier.
true
T/F In the muscles of the limbs, the origin is usually the immobile muscle attachment.
true
T/F Muscle cells store more creatine phosphate than ATP resulting in the muscle having a reserve source of energy.
true
T/F Muscle tone is the small amount of tautness or tension in the muscle due to weak, involuntary contractions of its motor units.
true
T/F Neurons in the CNS are organized into functional groups.
true
T/F One of the functions of skeletal muscle contraction is production of heat.
true
T/F One of the important functions of skeletal muscle contraction is production of heat.
true
T/F Peristalsis is characteristic of smooth muscle.
true
T/F Reflexes are rapid, automatic responses to stimuli that will produce the same effect every time.
true
T/F The effect of a neurotransmitter on the muscle cell membrane is to modify its ion permeability properties temporarily.
true
T/F The peripheral nervous system is divided into afferent and efferent divisions.
true
T/F When a muscle fiber contracts, the I bands diminish in size, the H zones disappear, and the A bands move closer together but do not diminish in length.
true
Which type of muscle is found in the wall of hollow organs? A)skeletal muscle B)multi unit smooth muscle C)unitary smooth muscle D)cardiac muscle
unitary smooth muscle
Immediately after an action potential has peaked, which of the following channels will open? A)voltage gated calcium channels B)voltage gated potassium channels C)chemically gated chloride channels D)voltage gated sodium channels
voltage gated potassium channels
An action potential releases neurotransmitter from a neuron by opening which of the following channels? A)chemically gated Ca2+ channels B)voltage-gated Na+ channels C)voltage-gated Ca2+ channels D)voltage-gated K+ channels
voltage-gated Ca2+ channels
The depolarization phase of an action potential results from the opening of which channels? A)chemically gated Na+ channels B)voltage-gated K+ channels C)voltage-gated Na+ channels D)chemically gated K+ channels
voltage-gated Na+ channels
The generation of an action potential in a neuron requires the presence what type of membrane channels? Select the best answer. A)voltage-gated channels B)leakage channels C)chemically gated channels D)membrane channels are not required
voltage-gated channels
Which type of muscle fiber has a large quantity of glycogen and mainly uses glycolysis to synthesize ATP? A)white fast twitch fibers B)red slow twitch fibers
white fast twitch fibers
Drag the terms on the left to the appropriate blanks on the right to complete the sentences. How a smooth increase in muscle force is produced. A)Muscle tone B)Tetanus C)Multiple motor unit summation D)Maximal stimulus E)Wave summation
Multiple motor unit summation
Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. How a smooth increase in muscle force is produced. A)Muscle tone B)Multiple motor unit summation C)Isometric contraction D)Isotonic contraction E)Tetanus
Multiple motor unit summation
Which of the following statements is most accurate? A)Muscle tension remains relatively constant during isotonic contraction. B)The I band lengthens during isotonic contraction. C)T tubules may be sliding during isotonic contraction. D)Myofilaments slide during isometric contractions.
Muscle tension remains relatively constant during isotonic contraction.
Drag the terms on the left to the appropriate blanks on the right to complete the sentences. Determined by alternating motor units of a muscle organ even when the muscle is at rest. A)Muscle tone B)Tetanus C)Multiple motor unit summation D)Maximal stimulus E)Wave summation
Muscle tone
Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. Determined by alternating motor units of a muscle organ even when the muscle is at rest. A)Muscle tone B)Multiple motor unit summation C)Isometric contraction D)Isotonic contraction E)Tetanus
Muscle tone
In which type of axon will velocity of action potential conduction be the fastest? A)Myelinated axons with the smallest diameters B)Myelinated axons with the largest diameter C)Unmyelinated axons with the largest diameter D)Unmyelinated axons of the shortest length
Myelinated axons with the largest diameter
BMD (2,3-butanedione 2-monoximime) inhibits myosin, such that ATP can bind to myosin but myosin is unable to hydrolyze the bound ATP. What effect would BMD have on the cross bridge cycle? A)Myosin heads would remain attached to actin, unable to detach. B)Myosin heads would remain detached, unable to cock. C)Tropomyosin would not move, and the active sites on actin would not be exposed. D)Myosin heads would remain attached to actin, unable to perform the power stroke.
Myosin heads would remain detached, unable to cock.
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 the intracellular calcium concentration would rise. Which of the following would you expect to happen? A)Calcium would be transported to the sarcoplasmic reticulum therefore contractions would cease. B)The fiber would twitch uncontrollably due to excessive calcium bound to troponin. C)Myosin would be able to bind to the exposed binding sites on thin filaments but it would not be able to detach. D)No change would occur in a muscle that was relaxed to begin with.
Myosin would be able to bind to the exposed binding sites on thin filaments but it would not be able to detach.
The diffusion of what ion, across the neuronal membrane, is responsible for the local currents that depolarize regions of the axon to threshold? A)Ca2+ (calcium) B)voltage-gated Na+ (sodium) channels C)K+ (potassium) D0Na+ (sodium)
Na+ (sodium)
The concentrations of which two ions are highest outside the cell. A)Na+ and A- (negatively charged proteins) B)K+ and A- (negatively charged proteins) C)K+ and Cl- D)Na+ and Cl-
Na+ and Cl-
The Na+-K+ pump actively transports both sodium and potassium ions across the membrane to compensate for their constant leakage. In which direction is each ion pumped? A)Na+ is pumped out of the cell and K+ is pumped into the cell. B)Both Na+ and K+ are pumped into the cell. C)Both Na+ and K+ are pumped out of the cell. D)K+ is pumped out of the cell and Na+ is pumped into the cell.
Na+ is pumped out of the cell and K+ is pumped into the cell.
How do neurofibrils differ from nerve fibers? A)Neurofibrils are confined to dendrite receptor areas and are consequently not found in nerve fibers. B)Neurofibrils are axon subunits that are bundled together to make up a single nerve fiber. C)Neurofibrils are cytoskeletal intermediate filaments maintaining cell shape, but they do not conduct impulses. D)There is no real difference, since they are both capable of impulse conduction away from a neuron.
Neurofibrils are cytoskeletal intermediate filaments maintaining cell shape, but they do not conduct impulses.
Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. Words can be used more than once. Where the axon of a motor neuron connects with the muscle fibers. A)Acetylocholine B)Neuromuscular junction C)Sodium ions D)Calcium ions E)Acetylcholinesterase
Neuromuscular junction
Drag the terms on the left to the appropriate blanks on the right to complete the sentences. Terms may be used more than once. May be involved in complex, exacting types of mental processing. A)Diverging circuit B)Reverberating circuit C)Parallel after-discharge circuit D)Converging circuit
Parallel after-discharge circuit
Both A and B
Which areas of this neuron would be classified as receptive regions? A)Both A and E B)D only C)Both A and B D)E only
How do action potential propagation speeds compare in myelinated and unmyelinated axons? A)Propagation is faster in unmyelinated axons. B)Propagation in unmyelinated axons is faster over short distances, but propagation is faster in myelinated axons over long distances. C)Propagation speeds are similar in both axon types. D)Propagation is faster in myelinated axons.
Propagation is faster in myelinated axons.
The "rest and recovery" period, where the muscle restores depleted reserves, includes all of the following processes EXCEPT __________. A)Oxygen rebinds to myoglobin. B)Pyruvic acid is converted back to lactic acid. C)Glycogen is synthesized from glucose molecules. D)ATP is used to rephosphorylate creatine into creatine phosphate.
Pyruvic acid is converted back to lactic acid.
Drag the terms on the left to the appropriate blanks on the right to complete the sentences. Terms may be used more than once. Involved in control of rhythmic activities such as breathing. A)Diverging circuit B)Reverberating circuit C)Parallel after-discharge circuit D)Converging circuit
Reverberating circuit
Some nerve fibers of the peripheral nervous system have the ability to regenerate after damage has occurred. Which of the following cells is most responsible for aiding in this regulation? A)oligodendrocytes B)astrocytes C)satellite cells D)Schwann cells
Schwann cells
Which of the following peripheral nervous system (PNS) neuroglia form the myelin sheaths around larger nerve fibers in the PNS? A)oligodendrocytes B)Schwann cells C)satellite cells D)astrocytes
Schwann cells
Which of the following statements is true? A)Smooth muscle cells have T tubules. B)Cardiac muscle cells have many nuclei. C)Skeletal muscle cells are long and cylindrical with many nuclei. D)Cardiac muscle cells are found in the heart and large blood vessels.
Skeletal muscle cells are long and cylindrical with many nuclei.
Which of the following statements best illustrates the fact that skeletal muscle is voluntary muscle? A)Skeletal muscle fibers are innervated by somatic motor neurons. B)Skeletal muscle appears striated due to the structure of the sarcomeres. C)Skeletal muscle is wrapped in several layers of connective tissue. The deepest layer being the endomysium. D)The shivering reflex aids in maintaining body temperature.
Skeletal muscle fibers are innervated by somatic motor neurons.
Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. Words can be used more than once. It diffuses across the cell membrane resulting in depolarization. A)Acetylocholine B)Neuromuscular junction C)Sodium ions D)Calcium ions E)Acetylcholinesterase
Sodium ions
Drag the terms on the left to the appropriate blanks on the right to complete the sentences. Stimulation of a postsynaptic neuron by many terminals at the same time. A)Threshold stimulus B)Subthreshold stimulus C)Spatial summation D)Temporal summation
Spatial summation
Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. Stimulation of a postsynaptic neuron by many terminals at the same time. A)Spatial summation B)Threshold stimulus C)Subthreshold stimulus D)Temporal summation
Spatial summation
Drag the terms on the left to the appropriate blanks on the right to complete the sentences. An insufficient stimulus. A)Threshold stimulus B)Subthreshold stimulus C)Spatial summation D)Temporal summation
Subthreshold stimulus
Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. An insufficient stimulus to reach an action potential. A)Spatial summation B)Threshold stimulus C)Subthreshold stimulus D)Temporal summation
Subthreshold stimulus
Drag the terms on the left to the appropriate blanks on the right to complete the sentences. Numerous nerve impulses arriving at a synapse at closely timed intervals exert a cumulative effect. A)Threshold stimulus B)Subthreshold stimulus C)Spatial summation D)Temporal summation
Temporal summation
Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. Numerous nerve impulses arriving at a synapse at closely timed intervals exert a cumulative effect. A)Spatial summation B)Threshold stimulus C)Subthreshold stimulus D)Temporal summation
Temporal summation
Drag the terms on the left to the appropriate blanks on the right to complete the sentences. Continued sustained smooth contraction due to rapid stimulation. A)Muscle tone B)Tetanus C)Multiple motor unit summation D)Maximal stimulus E)Wave summation
Tetanus
Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. Continued sustained smooth contraction due to rapid stimulation. A)Muscle tone B)Multiple motor unit summation C)Isometric contraction D)Isotonic contraction E)Tetanus
Tetanus
What role does tropomyosin play in the cross bridge cycle? A)Tropomyosin pushes the myosin head away, causing cross bridge detachment. B)Tropomyosin binds to calcium, causing muscle relaxation. C)The displacement of tropomyosin exposes the active sites of actin, allowing cross bridges to form. D)Tropomyosin moves the actin filament relative to the myosin filament.
The displacement of tropomyosin exposes the active sites of actin, allowing cross bridges to form.
How does the myosin head obtain the energy required for activation? A)The energy comes from the direct phosphorylation of ADP by creatine phosphate. B)The energy comes from the hydrolysis of GTP. C)The energy comes from the hydrolysis of ATP. D)The energy comes from oxidative phophorylation.
The energy comes from the hydrolysis of ATP.
Why does regeneration of the action potential occur in one direction, rather than in two directions? A)The activation gates of voltage-gated Na+ channels close in the node, or segment, that has just depolarized. B)The inactivation gates of voltage-gated Na+ channels close in the node, or segment, that has just fired an action potential. C)The activation gates of voltage-gated K+ channels open in the node, or segment, that has just depolarized. D)The inactivation gates of voltage-gated K+ channels close in the node, or segment, that has just fired an action potential.
The inactivation gates of voltage-gated Na+ channels close in the node, or segment, that has just fired an action potential.
Which of the following is NOT a difference between graded potentials and action potentials? A)Greater stimulus intensity results in larger graded potentials, but not larger action potentials. B)Graded potentials can result from the opening of chemically gated channels; action potentials require the opening of voltage-gated channels. C)Graded potentials occur along dendrites, whereas action potentials occur along axons. D)The magnitude of action potentials decrease as the impulse travels further away from the start of the impulse while graded potentials do not decrease in magnitude.
The magnitude of action potentials decrease as the impulse travels further away from the start of the impulse while graded potentials do not decrease in magnitude.
Based on what you know of the relationship between the thick and the thin filaments, what would happen if a disorder existed that caused a person to produce no tropomyosin? A)The muscle would never contract. B)Actin will spontaneously fall apart. C)The muscle would be weaker than normal. D)The muscle tissues would never be able to relax.
The muscle tissues would never be able to relax.
What is the function of the myelin sheath? A)The myelin sheath decreases the resistance of the axonal membrane to the flow of charge. B)The myelin sheath decreases the speed of action potential conduction from the initial segment to the axon terminals. C)The myelin sheath increases the speed of action potential conduction from the initial segment to the axon terminals. D)The myelin sheath increases the insulation along the entire length of the axon.
The myelin sheath increases the speed of action potential conduction from the initial segment to the axon terminals.
You discover that a new chemical compound interacts with K+ voltage-dependent channels. What would be the effect on a neuron if the chemical came into contact with the axonal membrane? A)The cell would be unable to generate a resting potential. B)The cell would die. C)The cell would be unable to depolarize. D)The neuron would be unable to repolarize.
The neuron would be unable to repolarize.
In a myelinated axon, how do the nodes of Ranvier differ from other segments of the same axon? A)The nodes are more permeable to ions. B)The nodes are longer segments of the axon. C)The nodes are less numerous. D)The nodes are wrapped in myelin.
The nodes are more permeable to ions.
During action potential propagation in an unmyelinated axon, why doesn't the action potential suddenly "double back" and start propagating in the opposite direction? A)The extracellular sodium concentration is too low around the previous axonal segment for an action potential to be (re)generated. B)New action potential generation near the soma repels previously generated action potentials, causing them to always propagate away from the soma. C)The previous axonal segment is in the refractory period. D)Positive charges only move in one direction after they enter the cell.
The previous axonal segment is in the refractory period.
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 it only begins aerobic respiration by the time the run has finished. B)Since the exercise was mostly aerobic exercise, the runners' bodies have not yet realized the run is over. C)Slow oxidative fibers are recruited last and have only started to work at completion of the run. 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.
What structure is the functional unit of contraction in a skeletal muscle fiber? A)The sarcomere B)The junctional folds of the sarcolemma C)The triad D)The cross bridge
The sarcomere
The myelin on myelinated neurons can be degraded or destroyed in diseases such as multiple sclerosis-a process called demyelination. If a myelinated neuron was affected by demyelination, how would this affect action potentials in that neuron? A)The speed of action potential propagation would be faster. B)Action potentials would propagate in both directions along the axon. C)Initial generation of action potentials would be more difficult. D)The speed of action potential propagation would be slower.
The speed of action potential propagation would be slower.
During contraction, what prevents actin myofilaments from sliding backward when a myosin head releases? A)There are always some myosin heads attached to the actin myofilament when other myosin heads are detaching. B)The actin myofilament can only move in one direction relative to the myosin filament. C)Calcium blocks the active sites on actin. D)The cross bridge remains in place, preventing the actin myofilament from sliding.
There are always some myosin heads attached to the actin myofilament when other myosin heads are detaching.
What is the basic condition when a neuron is described as polarized? A)Na+ is found outside of the neuron and K+ is found inside of the cell. B)There is a separation of positive and negative charges across a membrane. C)Na+ is found outside of the neuron. D)There are large, protein anions inside the neuron.
There is a separation of positive and negative charges across a membrane.
Which of the following describes the cells of unitary smooth muscle? A)They depend upon recruitment using the autonomic nervous system. B)They consist of muscle fibers that are structurally independent of each other. C)They exhibit spontaneous action potentials. D)They are used for vision and hair raising.
They exhibit spontaneous action potentials.
Drag the terms on the left to the appropriate blanks on the right to complete the sentences. Any stimulus below this intensity will result in no response in a neuron. A)Threshold stimulus B)Subthreshold stimulus C)Spatial summation D)Temporal summation
Threshold stimulus
Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. Any stimulus at or above this level will result in action potential. A)Spatial summation B)Threshold stimulus C)Subthreshold stimulus D)Temporal summation
Threshold stimulus
An excitatory event may result in an action potential, but this will be less likely if the excitatory stimulus occurs during the response to the stimulus observed in the graph.
Which of the following is true regarding a response to an excitatory event which might occur soon after the initial stimulus indicated in the graph? A)An excitatory event will be more likely to generate an action potential if it occurs during the response to the stimulus observed in the graph. B)An excitatory event may result in an action potential, but this will be less likely if the excitatory stimulus occurs during the response to the stimulus observed in the graph. C)No action potential can be induced in the neuron by an excitatory event if it occurs during the response observed in the graph.
the region between 2 and 3
Which of the following regions best identifies where myosin would have maximum cross-bridge access to actin? A)the region between 3 and 5 B)the region between 2 and 3 C)the region between 1 and 2 D)the region identified at 4
Both responses are examples of graded potentials.
Which of the following statements is true of both membrane potential responses shown in the graphs? A)Both responses are examples of excitatory postsynaptic potentials (EPSPs). B)Both responses are examples of graded potentials. C)Both responses are examples of action potentials. D)Both responses are examples of inhibitory postsynaptic potentials (IPSPs).
Both responses are examples of graded potentials.
Which of the following statements is true of both membrane potential responses shown in the graphs? A)Both responses are examples of excitatory postsynaptic potentials (EPSPs). B)Both responses are examples of inhibitory postsynaptic potentials (IPSPs). C)Both responses are examples of action potentials. D)Both responses are examples of graded potentials.
E
Which of the neuroglial cell types shown are found in the PNS? A)A B)B C)C D)D E)E
D
Which of the neuroglial cell types shown control the flow of cerebrospinal fluid within the CNS? A)A B)B C)C D)D
A
Which of the neuroglial cell types shown form myelin sheaths within the CNS? A)A B)B C)C D)F
B
Which of the neuroglial cell types shown is the most abundant in the CNS? A)A B)B C)C D)D E)E
actin
Which protein is indicated by the letter A? A)myosin B)troponin C)keratin D)actin
myosin
Which protein is indicated by the letter E? A)actin B)troponin C)myosin D)tropomyosin
What is the relationship between the number of motor neurons recruited and the number of skeletal muscle fibers innervated? A)Typically, hundreds of skeletal muscle fibers are innervated by a single motor neuron. B)Motor neurons always innervate thousands of skeletal muscle fibers. C)A skeletal muscle fiber is innervated by multiple motor neurons. D)A motor neuron typically innervates only one skeletal muscle fiber.
Typically, hundreds of skeletal muscle fibers are innervated by a single motor neuron.
Drag the terms on the left to the appropriate blanks on the right to complete the sentences. The situation in which contractions become stronger due to stimulation before complete relaxation occurs. A)Muscle tone B)Tetanus C)Multiple motor unit summation D)Maximal stimulus E)Wave summation
Wave summation
the voltage measured across the axon membrane at a specific point as an action potential travels past
What change in a neuron is being measured in the graph? A)the voltage measured between the neuron cell body and the axonal terminals B_the voltage measured across the axon membrane at a specific point as an action potential travels past C)the voltage measured across the axon membrane at various points along an axon at a specific instance during an action potential D)the speed of an action potential as it moves down the length of an axon
protection from overstretching
What is the function of the filaments found in ranges 1-2 and 6-7 but no other ranges? A)neurological sensing of the muscle's tension B)protection from overstretching C)a connection between the myosin fibers and a calcium source D)adding strength to contraction
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
If a post synaptic cell is stimulated to threshold by temporal summation this implies that ________. A)the presynaptic neuron is initiating frequent IPSP B)a presynaptic neuron is initiating frequent EPSP C)the postsynaptic cell is sending frequent action potentials D)the postsynaptic cell can be influenced by only one presynaptic cell
a presynaptic neuron is initiating frequent EPSP
Which description is most appropriate for a myofibril? A)a single long protein structure found in the sarcomeres of a muscle cell B)a single long, thin organelle containing many proteins C)a single group of long muscle cells surrounded by a membrane D)a single long cell found within a muscle
a single long, thin organelle containing many proteins
What type of stimulus is required for an action potential to be generated? A)a threshold level depolarization B)a suprathreshold stimulus C)multiple stimuli D)hyperpolarization
a threshold level depolarization
The mechanism by which the neurotransmitter is returned to a presynaptic neuron's axon terminal is specific for each neurotransmitter. Which of the following neurotransmitters is broken down by an enzyme before being returned? A)acetylcholine B)glutamate
acetylcholine
Which of the following is an excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle? A)norepinephrine B)acetylcholine C)cholinesterase D)gamma aminobutyric acid
acetylcholine
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)elastic (titin) filaments C)acetylcholine receptors in the motor end plate D)actin of thin 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)the tropomyosin blocking the myosin once full contraction is achieved B)acetylcholinesterase breaks apart the ACh C)the action potential stops going down the overloaded T tubules D)calcium ions returning to the terminal cisternae
acetylcholinesterase breaks apart the ACh
Which of the following correctly describes a graded potential? A)voltage stimulus to initiate B)long distance signaling C)voltage regulated repolarization D)amplitude of various sizes
amplitude of various sizes
Which of the following describes the nervous system integrative function? A)senses changes in the environment B)responds to stimuli by gland secretion or muscle contraction C)analyzes sensory information, stores information, makes decisions
analyzes sensory information, stores information, makes decisions
Cold sores on the skin of the mouth occur when herpes simplex viruses that are dormant in neural ganglia become active and travel to the skin of the mouth. Which of the following is the mechanism by which these viruses travel from the ganglia (located within the head) to the skin of the mouth? A)transport along nerve impulses that travel down the axons B)anterograde axonal transport C)retrograde axonal transport D)travel of the viruses along neurofibrils
anterograde axonal transport
A neuron that has as its primary function the job of connecting other neurons is called a(n) ________. A)afferent neuron B)efferent neuron C)glial cell D)association neuron
association neuron
Neuroglia that control the chemical environment around neurons by buffering ions such as potassium and recapturing and recycling neurotransmitters are ________. A)microglia B)astrocytes C)Schwann cells D)oligodendrocytes
astrocytes
The concentration of ions in the chemical environment surrounding the neurons must be tightly regulated for neurons to function properly. Which of the following cells is most responsible for this? A)satellite cells B)astrocytes C)Schwann cells D)oligodendrocytes
astrocytes
Where are action potentials regenerated as they propagate along a myelinated axon? A)at the nodes of Ranvier B)at the myelinated segments C)at the axon hillock D)at every segment of the axon
at the nodes of Ranvier
Which of the following is the conducting region of the neuron? A)soma B)terminal boutons C)axon D)dendrites
axon
Where in the neuron is an action potential initially generated? A)anywhere on the axon B)axon hillock C)soma and dendrites
axon hillock
During depolarization, which gradient(s) move(s) Na+ into the cell? A)both the electrical and chemical gradients B)only the chemical gradient C)Na+ does not move into the cell. Na+ moves out of the cell. D)only the electrical gradient
both the electrical and chemical gradients
The term central nervous system refers to the ________. A)peripheral and spinal nerves B)brain and spinal cord C)spinal cord and spinal nerves D)brain, spinal cord, and peripheral nerves
brain and spinal cord
A muscle fiber represents which organizational level of anatomy? A)cellular level B)tissue level C)organ level D)organelle level
cellular level
What part of the nervous system performs information processing and integration? A)sympathetic nervous system B)somatic nervous system C)parasympathetic nervous system D)central nervous system
central nervous system
Myofilaments represent which organizational level of anatomy? A)tissue level B)chemical level C)organ level D)cellular level
chemical level
Binding of a neurotransmitter to its receptors opens __________ channels on the __________ membrane. A)chemically gated; postsynaptic B)voltage-gated; postsynaptic C)voltage-gated; presynaptic D)chemically gated; presynaptic
chemically gated; postsynaptic
Which of the following is NOT one of the chemical classes into which neurotransmitters fall? A)gases and lipids B)chlorides C)amino acids D)peptides
chlorides
In a bedridden patient recovering from a badly fractured femur, disuse atrophy in the thigh muscles is caused by _________. A)decreased ability of muscle cells to produce ATP, resulting in decreased ability of the muscles to contract B)decreased ability to synthesize acetylcholine in the neurons that innervate the thigh muscles C)decreased synthesis of muscle proteins and/or increased breakdown of muscle proteins D)none of the above
decreased synthesis of muscle proteins and/or increased breakdown of muscle proteins
What is the type of chemical reaction used to rebuild ADP into ATP? A)dehydration synthesis B)rehydration synthesis C)hydrolysis
dehydration synthesis
If a neuron had a mutation that prevented the production of voltage-gated Na+ channels, what function would the neuron NOT be able to accomplish? A)resting membrane potentials B)graded hyperpolarization C)graded depolarization D)depolarization leading to action potentials
depolarization leading to action potentials
An action potential is self-regenerating because __________. A)depolarizing currents established by the influx of Na+ flow down the axon and trigger an action potential at the next segment B)depolarizing currents established by the influx of K+ flow down the axon and trigger an action potential at the next segment C)repolarizing currents established by the efflux of K+ flow down the axon and trigger an action potential at the next segment D)repolarizing currents established by the efflux of Na+ flow down the axon and trigger an action potential at the next segment
depolarizing currents established by the influx of Na+ flow down the axon and trigger an action potential at the next segment
The sliding filament model of contraction states that __________. A)during contraction, the thin myofilaments slide past the thick myofilaments so that calcium ions can be released from the sarcoplasmic reticulum B)during contraction, the thin myofilaments slide past T tubules so that the Z discs are overlapping C)during contraction, the thin myofilaments slide past the thick myofilaments so that the actin and myosin myofilaments no longer overlap D)during contraction, the thin myofilaments slide past the thick myofilaments so that the actin and myosin myofilaments overlap to a greater degree
during contraction, the thin myofilaments slide past the thick myofilaments so that the actin and myosin myofilaments overlap to a greater degree
Where in the cross bridge cycle does ATP hydrolysis occur? A)during the movement of tropomyosin to expose the active sites on actin B)during the power stroke C)during the cocking of the myosin head D)during the removal of calcium from troponin
during the cocking of the myosin head
A muscle that is lengthening while it produces tension is performing a(n) __________ contraction. A)concentric B)maximal C)eccentric D)isometric
eccentric
Binding of the neurotransmitter to its receptor causes the membrane to __________. A)hyperpolarize B)depolarize C)either depolarize or hyperpolarize
either depolarize or hyperpolarize
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)acetylcholine receptors in the motor end plate D)potassium (K+) leak channels
elastic (titin) filaments
Which of the following surrounds an individual muscle cell? A)endomysium B)fascicle C)perimysium D)epimysium
endomysium
Which of the following neurotransmitters inhibits pain and is mimicked by morphine, heroin, and methadone? A)acetylcholine B)nitric oxide C)serotonin D)endorphin
endorphin
Which neurotransmitter(s) is/are the body's natural pain killer? A)endorphins B)acetylcholine C)norepinephrine D)substance P
endorphins
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
enhance cellular communication during muscle contraction
These cells in the CNS have cilia that move in order to circulate cerebrospinal fluid ________. A)ependymal cells B)oligodendrocytes C)Schwann cells D)astrocytes
ependymal cells
Which membrane surrounds the others? A)exomysium B)endomysium C)perimysium D)epimysium
epimysium
Which membrane potential occurs because of the influx of Na+ through chemically gated channels in the receptive region of a neuron? A)inhibitory action potential B)excitatory postsynaptic potential C)action potential D)inhibitory postsynaptic potential
excitatory postsynaptic potential
Action potentials travel the length of the axons of motor neurons to the axon terminals. These motor neurons __________. A)extend from the brain to the sarcolemma of a skeletal muscle fiber B)arise in the epimysium of a skeletal muscle and extend to individual skeletal muscle fibers C)extend from the brain or spinal cord to the sarcolemma of a skeletal muscle fiber D)extend from the spinal cord to the sarcolemma of a skeletal muscle fiber
extend from the brain or spinal cord to the sarcolemma of a skeletal muscle fiber
T/F During isometric contraction, the energy used appears as movement.
false
T/F More Na+ than K+ leaks through neuron membranes because of the properties of the non-gated leak channels.
false
T/F Once a motor neuron has fired, all the muscle fibers in a muscle contract.
false
T/F Strong stimuli cause the amplitude of action potentials generated to increase.
false
T/F The all-or-none phenomenon as applied to nerve conduction states that the whole nerve cell must be stimulated for conduction to take place.
false
Addition of more mitochondria to a muscle fiber will have the least effect on ________. A)both slow and fast oxidative fibers B)fast oxidative fibers C)fast glycolytic fibers D)slow oxidative fibers
fast glycolytic fibers
Bipolar neurons are commonly ________. A)called neuroglial cells B)motor neurons C)found in ganglia D)found in the retina of the eye
found in the retina of the eye
Collections of nerve cell bodies in the peripheral nervous system are called ________. A)nerves B)tracts C)nuclei D)ganglia
ganglia
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)hydrolysis C)glycolysis D)the electron transport chain
glycolysis
Which of the following processes produces molecules of ATP and has two pyruvic acid molecules as end products? A)Krebs cycle and oxidative phosphorylation B)glycolysis C)hydrolysis of creatine phosphate
glycolysis
An inhibitory postsynaptic potential (IPSP) is associated with ________. A)lowering the threshold for an action potential to occur B)opening of voltage-regulated channels C)a change in sodium ion permeability D)hyperpolarization
hyperpolarization
When a neurotransmitter like GABA is acting in an inhibitory manner which of the following is likely a result of the GABA acting on the post synaptic cell? A)opening of chemically gated sodium channels B)depolarization of the postsynaptic cell membrane C)influx of positively charged ions into the postsynaptic cell D)hyperpolarization of the postsynaptic cell membrane
hyperpolarization of the postsynaptic cell membrane
Myasthenia gravis is sometimes treated medically with a treatment that involves ________. A)boosting the activity of the immune system B)suppressing the release of acetylcholine from synaptic vesicles C)suppressing the synthesis of acetylcholine D)inhibiting the action of acetylcholinesterase
inhibiting the action of acetylcholinesterase
What component of the reflex arc determines the response to a stimulus? A)sensory neuron B)receptor C)effector D)integration center
integration center
A neuron that has as its primary function the job of connecting other neurons is called a(n) ________. A)glial cell B)efferent neuron C)afferent neuron D)interneuron
interneuron
When neurotransmitter molecules bind to receptors in the plasma membrane of the receiving neuron, A)the receiving neuron becomes more negative inside. B)ion channels in the plasma membrane of the receiving neuron open. C)ion channels in the plasma membrane of the sending neuron open. D)vesicles in the synaptic terminal fuse to the plasma membrane of the sending neuron. E)the receiving neuron becomes more positive inside.
ion channels in the plasma membrane of the receiving neuron open.
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)stearic acid B)a strong base C)lactic acid D)hydrochloric acid
lactic acid
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)contraction C)refractory D)latent
latent
Meningitis can be caused by infection of the central nervous system by bacteria. Which cells would be most responsible for removing the infection? A)microglia B)Schwann cells C)oligodendrocytes D)satellite cells
microglia
Cross bridge formation between myosin heads and actin molecules is caused by the elevation of calcium ion concentration in the cytosol. During rigor mortis, this elevation of calcium ion concentration in the cytosol is permanent because ________. A)mitochondria stop producing ATP molecules required by the sarcoplasmic reticulum's calcium ion pumps B)troponin molecules bind irreversibly to calcium ions to prevent them from being removed from the cytosol C)tropomyosin molecules bind irreversibly to calcium ions to prevent them from being removed from the cytosol D)acetylcholine continues to stimulate the release of calcium ions from the sarcoplasmic reticulum
mitochondria stop producing ATP molecules required by the sarcoplasmic reticulum's calcium ion pumps
Which of the choices below describes the ANS? A)sensory neurons that convey information from somatic receptors in the head, body wall, and limbs and from receptors from the special senses of vision, hearing, taste, and smell to the CNS B)motor fibers that conduct nerve impulses from the CNS to skeletal muscles C)sensory and motor neurons that supply the digestive tract D)motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands
motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands
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)neurotransmitter release, motor neuron action potential, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke C)motor neuron action potential, neurotransmitter release, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke, sliding of myofilaments D)muscle cell action potential, neurotransmitter release, ATP-driven power stroke, calcium ion release from SR, sliding of myofilaments
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)large motor units with small, highly excitable neurons B)motor units with the longest muscle fibers 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
During development embryonic cells will fuse to form muscle fibers. This will result in ________. A)multinucleated muscle fibers that can extend as long as 30 centimeters B)interlocking of cells that can prevent the filaments from sliding C)the striations that appear in skeletal and cardiac muscle tissues D)the coordination of nerve signals to muscle fibers
multinucleated muscle fibers that can extend as long as 30 centimeters
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
no ATP is available to release attached actin and myosin molecules
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)cross bridge attachment would be optimum because of all the free binding sites on actin C)maximum force production would result because the muscle has a maximum range of travel D)no muscle tension could be generated
no muscle tension could be generated
Which of the following is not a chemical class of neurotransmitters? A)biogenic amine B)ATP and other purines C)amino acid D)nucleic acid
nucleic acid
In multiple sclerosis, the cells that are the target of an autoimmune attack are the _________. A)neurons B)muscle cells C)Schwann cells D)oligodendrocytes
oligodendrocytes
Schwann cells are functionally similar to ________. A)microglia B)ependymal cells C)oligodendrocytes D)astrocytes
oligodendrocytes
Which of the following is NOT a type of circuit? A)diverging circuits B)pre-synaptic circuits C)converging circuits D)reverberating circuits
pre-synaptic circuits
In a synapse, neurotransmitters are stored in vesicles located in the __________. A)synaptic cleft B)postsynaptic neuron C)presynaptic neuron
presynaptic neuron
Which neuron circuit pattern is involved in the control of rhythmic activities such as breathing? A)reverberating circuit B)converging circuit C)diverging circuit D)parallel after-discharge circuit
reverberating circuit
Slow oxidative muscle fibers are best suited for __________. A)running a marathon B)running a 100-yard dash C)hitting a baseball D)lifting heavy weights at the gym
running a marathon
The node-to-node "jumping" regeneration of an action potential along a myelinated axon is called __________. A)myelinated conduction B)saltatory conduction C)continuous conduction D)local conduction
saltatory conduction
How does troponin facilitate cross bridge formation? A)Troponin gathers excess calcium that might otherwise block actin's progress. B)Troponin hydrolyzes ATP, which provides the energy necessary for cross bridges to form. C)Troponin controls the position of tropomyosin on the thin filament, enabling myosin heads to bind to the active sites on actin. D)Troponin moves away from the active sites on actin, permitting cross bridge formation.
Troponin controls the position of tropomyosin on the thin filament, enabling myosin heads to bind to the active sites on actin.
What, specifically, is a cross bridge? A)tropomyosin covering the active sites on actin B)ATP binding to the myosin head C)calcium binding to troponin D)myosin binding to actin
myosin binding to actin
The interior surface of a neuron's plasma membrane at resting membrane potential will have a ________. A)negative charge and contains more sodium than outside of the cell B)positive charge and contains more sodium than outside of the cell C)positive charge and contains less sodium than outside of the cell D)negative charge and contains less sodium than outside of the cell
negative charge and contains less sodium than outside of the cell
A molecule that carries information across a synaptic cleft is a A)synapse. B)synaptic cleft. C)neurotransmitter. D)receiving neuron. E)sending neuron.
neurotransmitter.
What is the magnitude (amplitude) of an action potential? A)70 mV B)30 mV C)100 mV
100 mV
Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. Weight lifting A)Aerobic pathway B)Anaerobic pathway C)Direct phosphorylation
Direct phosphorylation
Drag the terms on the left to the appropriate blanks on the right to complete the sentences. Terms may be used more than once. Involved in activating fibers of a skeletal muscle such as the biceps muscle. A)Diverging circuit B)Reverberating circuit C)Parallel after-discharge circuit D)Converging circuit
Diverging circuit
Drag the terms on the left to the appropriate blanks on the right to complete the sentences. Terms may be used more than once. One incoming fiber triggers responses in ever-increasing numbers farther and farther along the circuit. A)Diverging circuit B)Reverberating circuit C)Parallel after-discharge circuit D)Converging circuit
Diverging circuit
Local anesthetics block voltage-gated Na+ channels, but they do not block mechanically gated ion channels. Sensory receptors for touch (and pressure) respond to physical deformation of the receptors, resulting in the opening of specific mechanically gated ion channels. Why does injection of a local anesthetic into a finger still cause a loss of the sensation of touch from the finger? A)The local anesthetic prevents Na+ from causing the initial depolarization of this sensory receptor. B)The local anesthetic prevents any type of repolarization of this sensory receptor. C)Touch stimulation of this sensory receptor requires that there be a simultaneous opening of voltage-gated Na+ channels and mechanically gated ion channels. D)Touch stimulation of this sensory receptor will open the mechanically gated ion channels, but action potentials are still not initiated because propagation of an action potential requires the opening of voltage-gated Na+ channels.
Touch stimulation of this sensory receptor will open the mechanically gated ion channels, but action potentials are still not initiated because propagation of an action potential requires the opening of voltage-gated Na+ channels.
What is the role of tropomyosin in skeletal muscles? A)Tropomyosin serves as a contraction inhibitor by blocking the actin binding sites on the myosin molecules. B)Tropomyosin is the chemical that activates the myosin heads. 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.
Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules.
The oxygen-binding protein found in muscle cells is ________. A)hemoglobin B)ATP C)myoglobin D)immunoglobin
myoglobin