A&p exam 3 study guide
What membrane potential must generally be met in order to achieve threshold? A) -30 mV B) -85 mV C) -55 mV D) -70 mV
-55 mV
What value best represents resting membrane potential of skeletal muscle cells? A) -90 mV B) +15 mV C) +35 mV D) 0 mV
-90 mV
Which number on the graph represents when voltage-gated sodium channels are open?
2
Which area on the graph shows when the neuron is in the relative refractory period?
4
Place these steps of the action potential in the correct order. 1. Sodium ions channels return to the resting state and repolarization continues. 2. Voltage-gated sodium ion channels activate, sodium ions enter, and the axon section depolarizes. 3. As potassium ion channels return to resting state, the axolemma may hyperpolarize before returning to the resting membrane potential. 4. A local potential depolarizes the axolemma of the trigger zone to threshold. 5. Sodium ion channels inactivate, and voltage-gated potassium ion channels activate, so sodium ions stop entering and potassium ions leave, beginning repolarization.
4, 2, 5, 1, 3
Place the following events of excitation in the correct order. 1. ion channels on the sarcolemma open and sodium ions enter the muscle fiber 2. the entry of sodium ions into the muscle fiber depolarizes the sarcolemma locally 3. acetylcholine is released from vesicles in the motor neuron into the synaptic cleft 4. an action potential arrives at the axon terminal of a motor neuron 5. acetylcholine binds to ligand-gated sodium ion channels in the motor end plate
4, 3, 5, 1, 2
What are possible products of glycolytic, or anaerobic, catabolism? A) ATP, pyruvate, and lactic acid B) oxygen only C) glucose only D) creatine phosphate only
ATP, pyruvate, and lactic acid
Which statement best describes the all-or-none principle? A) An action potential happens completely, or it doesn't happen at all. B) All voltage-gated sodium channels will open or none will open. C) Local, or graded, potentials will always become action potentials. D) All neurons conduct an action potential together, or none do.
An action potential happens completely, or it doesn't happen at all.
What best describes a converging circuit? A) An increasing number of neurons are excited down the pathway of the circuit. B) Axon terminals from multiple input neurons join onto a single postsynaptic neuron. C) One axon of an input neuron branches to make contact with multiple postsynaptic neurons. D) One neuron communicates with multiple parts of the brain.
Axon terminals from multiple input neurons join onto a single postsynaptic neuron
What do skeletal muscle tissue and cardiac muscle tissue share in common? A) Both skeletal and cardiac muscle tissues possess intercalated discs. B) Both skeletal and cardiac muscle tissues perform peristalsis. C) Both skeletal and cardiac muscle tissues are voluntary. D) Both skeletal and cardiac muscle tissues consist of striated muscle cells.
Both skeletal and cardiac muscle tissues consist of striated muscle cells.
What do skeletal muscle contractions share in common with smooth muscle contractions? A) Both types of contractions generate little force or a weak force. B) Both types of contractions result from thick and thin filaments sliding past one another. C) Both types of contractions consume very little ATP. D) Both types of contractions do not require calcium ions for a contraction to occur
Both types of contractions result from thick and thin filaments sliding past one another.
Which of the following must happen first in the order events at a chemical synapse? A) Calcium ion channels in the axon terminal open. B) Ion channels respond to the neurotransmitter and lead to a local potential, or possibly an action potential. C) Neurotransmitter binds to receptors on the postsynaptic neuron. D) Calcium ions cause synaptic vesicles to release neurotransmitters into the synaptic cleft.
Calcium ion channels in the axon terminal open.
The central region of the A band that lacks thin filaments is the: A) sarcomere. B) Z disc. C) H zone. D) I band
H zone
Clostridium botulinum is a bacterium that produces botulinum toxin that inhibits the release of acetylcholine. Which description best fits how muscle cells will respond to a lack of acetylcholine? A) Muscle cells will produce greater tension when there is a lack of acetylcholine. B) Muscle cells will experienced fused or complete tetanus when there is a lack of acetylcholine. C) Muscle cells will produce sustained contractions without relaxation when there is a lack of acetylcholine. D) Muscle cells will become paralyzed when there is a lack of acetylcholine
Muscle cells will become paralyzed when there is a lack of acetylcholine
Latrotoxin, produced by the poisonous black widow spider, increases the release of acetylcholine. How do muscle cells respond? A) Muscle cells will experience fused or complete tetanus when excess acetylcholine exists. B) Muscle cells will twitch irregularly when excess acetylcholine exists. C) Muscle cells will experience a longer latent period when excess acetylcholine exists. D) Muscle cells will become paralyzed when excess acetylcholine exists.
Muscle cells will experience fused or complete tetanus when excess acetylcholine exists.
Which of the following is an effect of myelination? A) Myelination increases the rate of mitosis in damaged neurons. B) Myelination increases the rate at which phagocytosis occurs in the brain. C) Myelination increases the volume of cerebrospinal fluid in circulation. D) Myelination increases the speed of conduction of action potentials.
Myelination increases the speed of conduction of action potentials.
Which statement best describes the function of myoglobin? A) Myoglobin catabolizes glycogen. B) Myoglobin stores oxygen in muscle cells. C) Myoglobin hydrolyzes ATP. D) Myoglobin is a source of ATP for muscles.
Myoglobin stores oxygen in muscle cells
Which of the following is descriptive of skeletal muscle fibers? A) Skeletal muscle fibers are smaller than most cells. B) Skeletal muscle fibers are striated. C) Skeletal muscle fibers lack a sarcolemma and myofibrils. D) Skeletal muscle fibers are uninucleate.
Skeletal muscle fibers are striated.
Using the information provided in this graph, which statement best summarizes the activity in this neuron? A) Positive charges are lost from the cell, making the inside more negative. B) The cell gains positive charges, making the inside less negative. C) The cells gains negative charges, making the inside more negative. D) The cell gains chloride ions, making the cell hyperpolarize.
The cell gains positive charges, making the inside less negative.11
What happens when troponin and tropomyosin block the active sites of actin? A) The muscle contraction increases tension. B) The muscle relaxes. C) The muscle produces a weak contraction. D) The muscle contraction reaches peak tension.
The muscle relaxes.
What is accomplished by the power stroke? A) The power stroke allows the myosin heads to bind to actin. B) The power stroke cocks the myosin head into its high-energy position. C) The power stroke results in myosin heads pulling actin toward the center of the sarcomere. D) The power stroke causes the myosin and actin filaments to shorten and contract.
The power stroke results in myosin heads pulling actin toward the center of the sarcomere.
Which of the following statements is the most accurate description of the sliding filament mechanism? A) Z discs slide over the thick and thin filaments. B) Thick filaments shorten while thin filaments remain unchanged. C) Thin filaments slide past thick filaments towards the M line. D) Both thick and thin filaments shorten.
Thin filaments slide past thick filaments towards the M line.
What anchors thin and elastic filaments in place within the myofibril? A) Z disc B) I band C) A band D) M line
Z disc
A triad consists of: A) actin filaments, troponin, and tropomyosin. B) myosin filaments, myosin heads, and myosin tails. C) a transverse tubule (T-tubule) and two terminal cisternae. D) a fascicle of skeletal muscle cells and its surrounding perimysium.
a transverse tubule (T-tubule) and two terminal cisternae
When is the generation of an action potential impossible, no matter the strength of the stimulus? A) relative refractory period B) absolute refractory period C) depolarization D) threshold
absolute refractory period
Cholinergic synapses use the neurotransmitter: A) norepinephrine. B) acetylcholine. C) epinephrine. D) serotonin.
acetylcholine.
During muscle contraction, myosin crossbridges bind to active sites on: A) actin. B) troponin. C) T-tubules. D) tropomyosin.
actin
Voltage-gated sodium channels have both an activation gate and: A) a threshold gate. B) a swinging gate. C) a leak gate. D) an inactivation gate
an inactivation gate
A local hyperpolarization that makes the membrane potential of the postsynaptic neuron more negative is: A) an excitatory postsynaptic potential (EPSP). B) a saltatory stimulus. C) an inhibitory postsynaptic potential (IPSP). D) a temporal stimulus.
an inhibitory postsynaptic potential (IPSP).
Because of their ability to rapidly divide during brain injury, which type of neuroglial cell would be more likely to form a brain tumor? A) Schwann cell B) astrocyte C) oligodendrocyte D) ependymal cell
astrocyte
Which neuroglial cell helps form the blood-brain barrier? A) astrocyte B) ependymal cell C) satellite cell D) oligodendrocyte
astrocyte
In response to physical inactivity, we expect to see muscles: A) increase numbers of myofibrils. B) atrophy. C) hypertrophy. D) increase the diameter of the muscle fiber.
atrophy
The conducting region of the neuron is the: A) cell body. B) dendrites. C) axon terminals (synaptic knobs). D) axon.
axon
What part of the neuron is a process that can generate and conduct action potentials? A) axon B) neurofibril C) cell body D) dendrite
axon
What specific part of the neuron communicates with a target cell and serves as the secretory region of the cell? A) axon terminals (synaptic knobs) B) myelin sheath C) dendrites D) cell body
axon terminals (synaptic knobs)
Which of the following are organs of the central nervous system? A) brain and spinal cord B) spinal cord and spinal nerves C) brain, cranial nerves, spinal cord, and spinal nerves D) brain and cranial nerves
brain and spinal cord
What ion triggers synaptic vesicles to release neurotransmitters into the synaptic cleft? A) sodium B) magnesium C) chlorine D) calcium
calcium
What is required for excitation-contraction coupling? A) ATP only B) calcium ions and ATP C) calcium ions only D) neither calcium ions nor ATP
calcium ions and ATP
What is the most metabolically active part of a neuron? A) cell body B) dendrites C) axon D) axon hillock
cell body
Which nervous system division is responsible for the integration of sensory information? A) central nervous system B) peripheral nervous system C) somatic motor division D) visceral motor division
central nervous system
The two structural divisions of the nervous system are the: A) somatic sensory division and visceral sensory system. B) sensory division and motor division. C) visceral motor division and somatic motor division. D) central nervous system and peripheral nervous system.
central nervous system and peripheral nervous system.
Bundles of axons known as tracts are part of the: A) ganglion. B) myelin sheath. C) central nervous system. D) peripheral nervous system.
central nervous system.
The majority of synapses in the nervous system are: A) mechanical. B) chemical. C) voltage. D) electrical
chemical
The presence of a synaptic cleft between cells is characteristic of: A) chemical synapse. B) electrical synapse. C) both chemical and electrical synapses. D) neither chemical nor electrical synapses.
chemical synapse
What type of synapse must have receptors to transmit signals? A) chemical synapse B) electrical synapse C) both chemical and electrical synapses D) neither chemical nor electrical synapses
chemical synapse
Ciliated ependymal cells: A) form myelin in the brain and spinal cord. B) help form the blood-brain barrier. C) circulate cerebrospinal fluid. D) serve as wandering phagocytes during brain injury.
circulate cerebrospinal fluid.
Branches that may occur along an axon are called: A) collaterals. B) hillocks. C) telodendria. D) dendrites.
collaterals.
The main immediate source of ATP (lasting about 10 seconds) as muscle contractions begin comes from: A) glycogen. B) glucose. C) fat. D) creatine phosphate.
creatine phosphate
The binding of a myosin head to an actin molecule is termed a: A) power stroke. B) synaptic cleft. C) crossbridge. D) triad.
crossbridge
Where should most of the potassium ions be located when a muscle cell is at rest? A) extracellular fluid B) cytosol of the muscle cell C) sarcoplasmic reticulum D) transverse tubules (T-tubules)
cytosol of the muscle cell
Once excitation-contraction coupling has occurred, calcium ion concentration increases dramatically in the: A) cytosol of the muscle fiber. B) sarcolemma. C) terminal cisterna. D) sarcoplasmic reticulum
cytosol of the muscle fiber.
The influx of positive charges makes the membrane potential more positive and is known as: A) depolarization. B) repolarization. C) hyperpolarization. D) polarization.
depolarization
What is more likely to promote an action potential? A) absolute refractory period B) hyperpolarization C) repolarization D) depolarization
depolarization
What is NOT a function of the nervous system? A) control effectors B) integrate sensory information C) direct long-term functions such as growth D) sense the internal and external environments
direct long-term functions such as growth
The degree to which a muscle cell can stretch depends on its: A) distensibility. B) conductivity. C) excitability. D) contractility.
distensibility.
Which of the following wraps and surrounds an individual skeletal muscle fiber? A) epimysium B) endomysium C) perimysium D) sarcoplasmic reticulum
endomysium
During the recovery period after exercise, we breathe deeper and faster. This increased rate of respiration is known as: A) lactic acid buildup. B) muscular fatigue. C) excess postexercise oxygen consumption (EPOC). D) oxidative catabolism.
excess postexercise oxygen consumption (EPOC)
When an action potential arrives in an axon terminal, synaptic vesicles containing acetylcholine are released by: A) exocytosis. B) endocytosis. C) facilitated diffusion. D) osmosis.
exocytosis.
Both isotonic eccentric contractions and isotonic concentric contractions shorten the muscle
f
Cardiac muscles perform peristalsis to pump blood through the heart.
f
Contractility is the ability of a muscle to shorten.
f
Creatine phosphate provides 30-40 seconds of energy for muscle activity.
f
In a sarcomere, the light and dark bands are produced by alternating M lines and Z discs.
f
Myofilaments shorten to produce muscle contractions according to the sliding filament mechanism.
f
Saltatory conduction is slow due to the presence of insulating myelin around an axon.
f
Skeletal muscle fibers possess intercalated discs
f
The Na+/K+ ATPase (Na+/K+ pump) maintains the concentration gradients for sodium and potassium ions by moving two sodium ions out of the cell and three potassium ions into the cell.
f
The conduction of an action potential is faster in unmyelinated axons than in myelinated axons.
f
The entry of acetylcholine into a muscle cell through ligand-gated ion channels depolarizes the sarcolemma locally.
f
The sensory, or afferent, division of the peripheral nervous system carries information from the brain and spinal cord to effector organs.
f
Which of the following is NOT a function of neurons? A) forming the myelin sheath B) carrying sensory information C) transmitting motor information D) integration
forming the myelin sheath
When muscle fibers are stimulated so frequently they do not have an opportunity to relax, they are experiencing: A) wave summation. B) fused or complete tetanus. C) a twitch. D) unfused or incomplete tetanus
fused or complete tetanus.
What is NOT associated with a chemical synapse? A) neurotransmitter B) gap junction C) presynaptic neuron D) synaptic cleft
gap junction
What is the basic function of all muscle tissue? A) regulate body temperature B) generate muscle tension C) produce voluntary contractions D) stabilize joints
generate muscle tension
What is a necessary reactant for glycolytic, or anaerobic, catabolism to proceed? A) glucose B) myoglobin C) creatine phosphate D) oxygen
glucose
Which of the following is the most important excitatory neurotransmitter in the brain? A) dopamine B) glutamate C) GABA D) glycine
glutamate
A pathway of ATP production that results in the formation of lactic acid is: A) aerobic catabolism. B) oxidative catabolism. C) glycolytic catabolism. D) anabolism.
glycolytic catabolism.
A series of measurements with a voltmeter show a neuron's membrane potential becoming more negative, from -70 mV to -85 mV. This neuron is experiencing a: A) hyperpolarization phase. B) polarization phase. C) depolarization phase. D) repolarization phase.
hyperpolarization phase
Which of the following moves the membrane potential of the postsynaptic neuron closer to threshold? A) hyperpolarization B) inhibitory postsynaptic potential (IPSP) C) excitatory postsynaptic potential (EPSP) D) opening of potassium ion channels
inhibitory postsynaptic potential (IPSP)
Neuronal pools are collections of: A) bipolar neurons. B) efferent neurons. C) motor neurons. D) interneurons.
interneurons
What type of neuron, found within the CNS, performs the job of information processing? A) sensory (afferent) neurons B) bipolar neurons C) motor (efferent) neurons D) interneurons (association neurons)
interneurons (association neurons)
The type of contraction in which length of the muscle fibers do not change is called: A) tetany. B) isometric. C) isotonic eccentric. D) isotonic concentric.
isometric
What type of contraction requires the greatest amount of tension? A) miometric contraction B) isotonic concentric contraction C) isometric contraction D) isotonic eccentric contraction
isotonic eccentric contraction
What type of ion channel in neurons is always open? A) local B) regulated C) active D) leak
leak
Which of the following is the primary factor in the maintenance of a cell's negative charge during resting membrane potential? A) leak channels B) sodium-potassium pump C) voltage-gated channels D) ligand-gated channels
leak channels
Graded potentials: A) produce an effect that spreads actively across the membrane surface. B) may cause either depolarization or hyperpolarization. C) cause repolarization. D) produce an effect that increases with distance from the point of stimulation.
may cause either depolarization or hyperpolarization.
What specific type of gated channel opens or closes in response to physical distortion of the membrane surface, such as vibrations or pressure? A) ligand-gated B) chemically-gated C) mechanically-gated D) voltage-gated
mechanically-gated
Where are receptors for acetylcholine located? A) axon terminal B) motor end plate C) sarcomere D) triad
motor end plate
A single motor neuron together with all the skeletal muscle fibers it innervates is called a: A) synaptic cleft. B) motor unit. C) neuromuscular junction. D) motor end plate.
motor unit
The most common type of neuron in the human body is: A) multipolar. B) unipolar. C) pseudounipolar. D) bipolar.
multipolar
Resting muscles still have some degree of muscle tension produced by involuntary activation of motor units in the brain and spinal cord. This small amount of muscle tension is known as: A) isotonic contraction. B) fused (complete) tetanus. C) recruitment. D) muscle tone.
muscle tone
Larry's muscles weakened while he played tennis for hours on a hot summer afternoon. This inability to maintain intensity is defined as: A) hypotonia. B) atrophy. C) muscular fatigue. D) hypertonia.
muscular fatigue
Determine the fiber type in which propagation of an action potential will occur most quickly. A) myelinated type B fiber B) type C fiber C) unmyelinated type B fiber D) myelinated type A fiber
myelinated type A fiber
Which protein does NOT belong in a thin filament? A) tropomyosin B) myosin C) troponin D) actin
myosin
Smooth muscle and skeletal muscle both possess: A) myosin and actin filaments. B) motor end plates. C) transverse tubules (T-tubules). D) troponin.
myosin and actin filaments.
The synapse of a motor neuron with a muscle fiber is known as the: A) synaptic cleft. B) synaptic bulb. C) neuromuscular junction. D) motor end plate
neuromuscular junction
The same ________ can have different effects depending on the properties of the ________. A) substrate; enzyme B) neurotransmitter; receptor C) receptor; neurotransmitter D) hormone; neurotransmitter
neurotransmitter; receptor
During the absolute refractory period: A) no additional stimulus, no matter how strong, can produce an additional action potential. B) sodium ion channels are in their resting state (closed). C) each stimulus produces an action potential. D) a strong stimulus can produce an action potential.
no additional stimulus, no matter how strong, can produce an additional action potential.
Which of the following best describes a bipolar neuron? A) multiple axons and one dendrite B) one axon and one dendrite C) one axon that splits into two processes D) one axon and multiple, highly branched dendrites
one axon and one dendrite
Voltage-gated sodium channels are activated: A) during repolarization. B) only if the cell is depolarized to threshold. C) after voltage-gated potassium channels are activated. D) during hyperpolarization
only if the cell is depolarized to threshold.
What would most likely lead to an inhibitory postsynaptic potential (IPSP)? A) opening of sodium ion channels B) opening of potassium ion channels C) closure of chloride ion channels D) opening of calcium ion channels
opening of potassium ion channels
Which of the following promotes the depolarization stage? A) opening of voltage-gated potassium ion channels and potassium ions exit the cell B) closure of voltage-gated sodium ion channels C) opening of voltage-gated sodium ion channels and sodium ions enter the cell D) hydrolysis of ATP
opening of voltage-gated sodium ion channels and sodium ions enter the cell
Through which ATP-generating mechanism can long-lasting muscle contractions be sustained? A) anaerobic catabolism B) oxidative catabolism C) glycolysis D) creatine phosphate reaction
oxidative catabolism
A muscle cell experiencing resting membrane potential is: A) polarized. B) propagating an action potential. C) more negatively charged on its exterior than in its interior. D) experiencing depolarization.
polarized
During repolarization of a neuron: A) potassium ions move into the cell. B) potassium ions move out of the cell. C) sodium ions move out of the cell. D) sodium ions move into the cell.
potassium ions move out of the cell
Which of the following would NOT terminate the effects of the neurotransmitter? A) presence of calcium ions in the presynaptic neuron B) reuptake of neurotransmitter into the presynaptic neuron C) diffusion of the neurotransmitter into the extracellular fluid D) degradation of the neurotransmitter by enzymes
presence of calcium ions in the presynaptic neuron
After acetylcholinesterase (AChE) acts, the presynaptic neuron: A) reabsorbs acetylcholine. B) reabsorbs the choline. C) reabsorbs the acetate. D) reabsorbs synaptic vesicles.
reabsorbs the choline
Jorge tried to pick up his sofa but discover that it is much heavier than he expected. What must occur in the muscle to increase tension so he can pick up this heavy piece of furniture? A) recruitment of additional motor units B) tetanic spasm C) pliometric contraction D) isotonic eccentric contractions
recruitment of additional motor units
Between the start of the latent period and the start of the contraction period, there is a time interval during which the muscle cannot respond to another stimulus. This brief period is known as the: A) relaxation period. B) refractory period. C) tension period. D) action potential.
refractory period
What does the depolarization of the transverse tubules (T-tubules) promote? A) entry of sodium ions into the muscle fiber through voltage-gated sodium ion channels B) release of acetylcholine from vesicles in the motor neuron into the synaptic cleft C) release of calcium from the sarcoplasmic reticulum D) binding of acetylcholine to ligand-gated sodium ion channels
release of calcium from the sarcoplasmic reticulum
The Na+/K+ pump helps a muscle cell maintain a state of: A) resting membrane potential. B) depolarization. C) propagation. D) action potential.
resting membrane potential.
The plasma membrane of a muscle cell is known as the: A) sarcoplasmic reticulum. B) sarcolemma. C) sarcomere. D) myofibril.
sarcolemma
What is the functional contractile unit of the myofibril where muscle tension is produced? A) sarcomere B) A band C) sarcolemma D) I band
sarcomere
Muscle contraction can occur when: A) myosin filaments shorten. B) I bands remain unchanged. C) sarcomeres shorten. D) A bands lengthen.
sarcomeres shorten.
The storage and release of calcium ions is the key function of the: A) sarcoplasmic reticulum. B) sarcolemma. C) mitochondrion. D) sarcoplasm.
sarcoplasmic reticulum.
The autonomic nervous system does NOT carry signals to: A) skeletal muscle. B) cardiac muscle. C) smooth muscle. D) glands
skeletal muscle
Which of the following is controlled by the somatic motor division? A) skeletal muscle B) smooth muscle C) cardiac muscle D) glands
skeletal muscle
Sarah sensed a mosquito land on her arm and swatted it away with her hand. Which specific PNS division was responsible for the movement of Sarah's hand? A) autonomic nervous system B) somatic sensory division C) somatic motor division D) visceral sensory division
somatic motor division
Upon entering your house, you noticed the smell of cake baking in the oven. What division of the peripheral nervous system is responsible? A) visceral sensory division B) somatic motor division C) somatic sensory division D) visceral motor division
somatic sensory division
Summation that results from the cumulative effect of multiple synapses at multiple places on the neuron is designated: A) impulse transmission. B) spatial summation. C) hyperpolarization. D) temporal summation.
spatial
Type I fibers lack: A) speed. B) a blood supply. C) myoglobin. D) mitochondria.
speed
Which neuropeptide neurotransmitter is released from fibers transmitting sensory information about pain and temperature? A) endorphin B) neuropeptide Y C) substance P D) opioids
substance P
If the receptor site for a neurotransmitter were completely blocked: A) the presynaptic neuron would release a different neurotransmitter. B) a weaker action potential would result. C) synaptic transmission would fail. D) neurotransmitter release would stop.
synaptic transmission would fail.
ATP is required for a power stroke to be repeated during the contraction cycle
t
Bipolar neurons have one axon and one dendrite.
t
Calcium ion entry into the axon terminal is necessary for the release of neurotransmitter into the synaptic cleft in a chemical synapse.
t
Cindy's leg muscles displayed a state of hypotonia since her arm was recently removed from a cast.
t
Conduction speed of a nerve impulse is influenced by the diameter of the axon and the presence or absence of a myelin sheath.
t
Decreased oxygen availability leads to muscular fatigue.
t
During depolarization, the membrane potential becomes more positive
t
During the absolute refractory period, production of an additional action potential is not possible no matter how strong the stimulus.
t
Elastic fibers are important to muscle tissue since they resist excessive stretching and help muscle fibers spring back to its original length after being stretched.
t
Electrical gradients exist because sodium and potassium ions are separated on either side of the plasma membrane.
t
Electrical synapses are faster than chemical synapses due to the presence of gap junctions between cells.
t
Greater muscle tension results when muscle fibers are repeatedly stimulated.
t
Jack has decided to take up jogging as a way to enhance his endurance training.
t
Neurons are responsible for sending and receiving signals referred to as action potentials while neuroglial cells serve a variety of supportive functions.
t
Neurotransmitters can be either excitatory or inhibitory depending upon the receptor present on the postsynaptic neuron.
t
Regeneration of neural tissue in the peripheral nervous system (PNS) is possible only if the neuron's cell body remains intact.
t
The autonomic nervous system carries signals to cardiac muscle, smooth muscle, and glands
t
The function of the sarcoplasmic reticulum (SR) is to store and release calcium ions
t
The loss of potassium ions from the cell during the repolarization stage restores a membrane potential of -90 mV.
t
The return of calcium ions to the sarcoplasmic reticulum during muscle relaxation decreases the calcium ion concentration in the cytosol.
t
The two types of neural circuits are diverging and converging.
t
Type IIx fibers produce the fastest, strongest twitches of any muscle fiber type
t
When a second excitatory postsynaptic potential (EPSP) arrives at a single synapse before the effects of the first have disappeared, what results? A) temporal summation B) inhibition of the impulse C) spatial summation D) hyperpolarization
temporal summation
When a skeletal muscle fiber contracts: A) the H zone narrows while the I bands widen. B) the H zone and I bands narrow. C) the A bands shorten while the I bands lengthen. D) Z discs move farther apart while the A bands shorten.
the H zone and I bands narrow.
Within the PNS, a neuron will regenerate only if: A) scar tissue is removed by phagocytosis. B) the surrounding neuroglia regenerate first. C) the neuron was myelinated. D) the cell body remains intact.
the cell body remains intact.
If a resting axon increases its permeability to sodium ions: A) the outward movement of sodium ions will decrease. B) the membrane potential will repolarize. C) the membrane potential will hyperpolarize. D) the influx of sodium ions will increase and the membrane will depolarize
the influx of sodium ions will increase and the membrane will depolarize
Neurotransmitters that bind ionotropic receptors control: A) the movement of ions into or out of the postsynaptic neuron. B) the activation of G-proteins inside the postsynaptic neuron. C) the formation of a second messenger inside the postsynaptic neuron. D) some metabolic process inside the postsynaptic neuron.
the movement of ions into or out of the postsynaptic neuron.
The neuron that receives neurotransmitters from another neuron is called: A) the presynaptic neuron. B) the postsynaptic neuron. C) a Schwann cell. D) an oligodendrocyte.
the postsynaptic neuron.
Deep inward extensions of the sarcolemma form a tunnel-like network inside the muscle cell known as: A) myofibrils. B) transverse tubules (T-tubules). C) myofilaments. D) the sarcoplasmic reticulum.
transverse tubules (T-tubules).
Resting membrane potential is maintained by the sodium-potassium ion pump, or Na+/K+ ATPase, which brings: A) three potassium ions into the cytosol and two sodium ions into the extracellular fluid. B) two potassium ions into the cytosol and two sodium ions into the extracellular fluid. C) three potassium ions into the cytosol and three sodium ions into the extracellular fluid. D) two potassium ions into the cytosol and three sodium ions into the extracellular fluid.
two potassium ions into the cytosol and three sodium ions into the extracellular fluid.
Which type of fiber has the largest diameter? A) type A B) type B C) type C D) type D
type A
Which fiber type allows Frances to stand for hours in her job as a nurse? A) type IIx fiber B) type IIa fiber C) type III fiber D) type I fiber
type I fiber
The fastest muscle contraction would be produced by a: A) type I fiber. B) type III fiber. C) type IIx fiber. D) type IIa fiber.
type IIa fiber.
Repolarization begins as: A) voltage-gated potassium ion channels activate. B) sodium ions follow their electrochemical gradient into the cell. C) voltage-gated sodium ion channels activate. D) voltage-gated potassium ion channels begin to close.
voltage-gated potassium ion channels activate
What characteristic is NOT descriptive of cardiac muscle tissue? A) voluntary muscle contractions B) intercalated discs C) located in the heart D) striations
voluntary muscle contractions
Saltatory conduction occurs: A) when threshold has not yet been reached. B) when myelin sheaths are present. C) when myelin sheaths are absent. D) in gray matter.
when myelin sheaths are present.
Myelinated axons in the CNS are known as: A) gray matter. B) internodes. C) white matter. D) dark matter
white matter.
Where are neuronal pools located? A) within the CNS B) within the PNS C) within nerves D) within ganglia
within the CNS
