ch 11 practice quiz

Which statement best describes the all-or-none principle? -An action potential happens completely, or it doesn't happen at all. -All voltage-gated sodium channels will open or none will open. -Local, or graded, potentials will always become action potentials. -All neurons conduct an action potential together, or none do.

An action potential happens completely, or it doesn't happen at all.

What membrane potential must generally be met in order to achieve threshold?

-55mV

Summation that results from the cumulative effect of multiple synapses at multiple places on the neuron is designated: -spatial summation. -impulse transmission. -hyperpolarization. -temporal summation.

spatial summation

Which neuropeptide neurotransmitter is released from fibers transmitting sensory information about pain and temperature? -endorphin -neuropeptide Y -substance P -opioids

substance P

If the receptor site for a neurotransmitter were completely blocked:

synaptic transmission would fail.

When a second excitatory postsynaptic potential (EPSP) arrives at a single synapse before the effects of the first have disappeared, what results? -inhibition of the impulse -temporal summation -spatial summation -hyperpolarization

temporal summation

Within the PNS, a neuron will regenerate only if: -scar tissue is removed by phagocytosis. -the cell body remains intact. -the neuron was myelinated. -the surrounding neuroglia regenerate first.

the cell body remains intact

If a resting axon increases its permeability to sodium ions:

the influx of sodium ions will increase and the membrane will depolarize.

Neurotransmitters that bind ionotropic receptors control: -the formation of a second messenger inside the postsynaptic neuron. -the movement of ions into or out of the postsynaptic neuron. -some metabolic process inside the postsynaptic neuron. -the activation of G-proteins inside the postsynaptic neuron.

the movement of ions into or out of the postsynaptic neuron

Which of the following is not characteristic of neurons?

they are mitotic (mitosis=cell division)

Neurons are responsible for sending and receiving signals referred to as action potentials while neuroglial cells serve a variety of supportive functions. T/F

true

Neurotransmitters can be either excitatory or inhibitory depending upon the receptor present on the postsynaptic neuron.

true

The autonomic nervous system carries signals to cardiac muscle, smooth muscle, and glands.

true

The two types of neural circuits are diverging and converging.

true

Resting membrane potential is maintained by the sodium-potassium ion pump, or Na+/K+ ATPase, which brings:

two potassium ions into the cytosol and three sodium ions into the extracellular fluid.

Myelinated axons in the CNS are known as:

white matter

Where are neuronal pools located? within nerves within the CNS within ganglia within the PNS

within the CNS

Bundles of axons known as tracts are part of the:

central nervous system

Which nervous system division is responsible for the integration of sensory information? -visceral motor division -peripheral nervous system -central nervous system -somatic motor division

central nervous system

The two structural divisions of the nervous system are the: somatic sensory division and visceral sensory system central nervous system and peripheral nervous system sensory division and motor division visceral motor division and somatic motor division.

central nervous system and peripheral nervous system

The majority of synapses in the nervous system are: -electrical. -chemical. -voltage. -mechanical.

chemical

The presence of a synaptic cleft between cells is characteristic of:

chemical synapse

What type of synapse must have receptors to transmit signals? -electrical synapse -chemical synapse -both chemical and electrical synapses -neither chemical nor electrical synapses

chemical synapse

Ciliated ependymal cells:

circulate cerebrospinal fluid

The sensory, or afferent, division of the peripheral nervous system carries information from the brain and spinal cord to effector organs. T/F

false

Which of the following is NOT a function of neurons?

forming the myelin sheath

What is NOT associated with a chemical synapse?

gap junction

Which of the following is the most important excitatory neurotransmitter in the brain? glycine glutamate dopamine GABA

glutamate

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: -polarization phase. -hyperpolarization phase. -repolarization phase. -depolarization phase.

hyperpolarization phase

Which neuroglial cell helps form the blood-brain barrier? -oligodendrocyte -astrocyte -satellite cell -ependymal cell

idkdik not D

Repolarization begins as: -voltage-gated potassium ion channels activate. -voltage-gated potassium ion channels begin to close. -sodium ions follow their electrochemical gradient into the cell. -voltage-gated sodium ion channels activate.

idkidk not D

Which of the following is controlled by the somatic motor division?

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?

somatic motor division

Bipolar neurons have one axon and one dendrite. T/F

true

Calcium ion entry into the axon terminal is necessary for the release of neurotransmitter into the synaptic cleft in a chemical synapse.

true

Conduction speed of a nerve impulse is influenced by the diameter of the axon and the presence or absence of a myelin sheath.

true

During the absolute refractory period, production of an additional action potential is not possible no matter how strong the stimulus. T/F

true

Electrical synapses are faster than chemical synapses due to the presence of gap junctions between cells T/F

true

Saltatory conduction occurs:

when myelin sheaths are present

Which of the following must happen first in the order events at a chemical synapse? -Calcium ions cause synaptic vesicles to release neurotransmitters into the synaptic cleft. -Neurotransmitter binds to receptors on the postsynaptic neuron. -Calcium ion channels in the axon terminal open. -Ion channels respond to the neurotransmitter and lead to a local potential, or possibly an action potential.

Calcium ion channels in the axon terminal open.

Which of the following is an effect of myelination? -Myelination increases the rate at which phagocytosis occurs in the brain. -Myelination increases the rate of mitosis in damaged neurons. -Myelination increases the volume of cerebrospinal fluid in circulation. -Myelination increases the speed of conduction of action potentials.

Myelination increases the speed of conduction of action potentials.

Diffusion of ___ is the prime cause of depolarization.

Na+

During the absolute refractory period: -sodium ion channels are in their resting state (closed). -each stimulus produces an action potential. -no additional stimulus, no matter how strong, can produce an additional action potential. -a strong stimulus can produce an action potential.

no additinal stimulus, no matter how strong, can produce an additional action potential

Which of the following best describes a bipolar neuron?

one axon and one dendrite

Voltage-gated sodium channels are activated:

only if the cell is depolarized to threshold.

The neuron that receives neurotransmitters from another neuron is called: -the postsynaptic neuron. -the presynaptic neuron. -a Schwann cell. -an oligodendrocyte.

postsynaptic neuron

During repolarization of a neuron: -potassium ions move out of the cell. -sodium ions move out of the cell. -sodium ions move into the cell. -potassium ions move into the cell.

potassium ions move out of the cell

Which of the following would NOT terminate the effects of the neurotransmitter?

presence of calcium ions in the presynaptic neuron

After acetylcholinesterase (AChE) acts, the presynaptic neuron: -reabsorbs acetylcholine. -reabsorbs synaptic vesicles. -reabsorbs the acetate. -reabsorbs the choline.

reabsorb the choline

Upon entering your house, you noticed the smell of cake baking in the oven. What division of the peripheral nervous system is responsible?

somatic sensory division

The conducting region of the neuron is the:

axon

What part of the neuron is a process that can generate and conduct action potentials?

axon

What specific part of the neuron communicates with a target cell and serves as the secretory region of the cell? -myelin sheath -axon terminals (synaptic knobs) -dendrites -cell body

axon terminals (synaptic knobs)

What best describes a converging circuit?

axon terminals from multiple input neurons join onto a single postsynaptic neuron

Which of the following are organs of the central nervous system?

brain and spinal cord

What ion triggers synaptic vesicles to release neurotransmitters into the synaptic cleft? -chlorine -magnesium -sodium -calcium

calcium

What is the most metabolically active part of a neuron?

cell body

Branches that may occur along an axon are called:

collaterals

The same ________ can have different effects depending on the properties of the ________.

neurotransmitter; receptor

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

What would most likely lead to an inhibitory postsynaptic potential (IPSP)?

??????

The autonomic nervous system does NOT carry signals to:

???????

Regeneration of neural tissue in the peripheral nervous system (PNS) is possible only if the neuron's cell body remains intact. T/F

True

Which type of fiber has the largest diameter?

Type A

When is the generation of an action potential impossible, no matter the strength of the stimulus?

absolute refractory period

Cholinergic synapses use the neurotransmitter:

acetylcholine

The first thing that occurs after the axon terminal releases acetylcholine is that- -the troponin blocks the tropomyosin. -calcium ions return to the terminal cisternae of the sarcoplasmic reticulum. -calcium diffuses into the axon terminal of the motor neuron. -acetylcholine diffuses across the synaptic cleft. -the tropomyosin blocks the myosin.

acetylcholine diffuses across the synaptic cleft

After nervous stimulation stops, what prevents acetylcholine in the synaptic cleft from continuing to stimulate contraction? -calcium ions returning to the sarcoplasmic reticulum -the tropomyosin blocking the myosin once full contraction is achieved -acetylcholinesterase destroying the acetylcholine -the action potential stops going down the overloaded T tubules

acetylcholinesterase destroying the acetylcholine

Voltage-gated sodium channels have both an activation gate and: -a threshold gate. -a swinging gate. -a leak gate. -an inactivation gate.

an inactivation gate

A local hyperpolarization that makes the membrane potential of the postsynaptic neuron more negative is: an excitatory postsynaptic potential (EPSP) an inhibitory postsynaptic potential (IPSP) a temporal stimulus a saltatory 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?

astrocyte

The influx of positive charges makes the membrane potential more positive and is known as: hyperpolarization repolarization depolarization polarization

depolarization

What is more likely to promote an action potential? -hyperpolarization -repolarization -absolute refractory period -depolarization

depolarization

What is NOT a function of the nervous system? -direct long-term functions such as growth -integrate sensory information -control effectors -sense the internal and external environments

direct long-term functions such as growth

Which of the following moves the membrane potential of the postsynaptic neuron closer to threshold?

excitatory postsynaptic potential (EPSP)

Saltatory conduction is slow due to the presence of insulating myelin around an axon. T/F

false

The conduction of an action potential is faster in unmyelinated axons than in myelinated axons.

false

Neuronal pools are collections of:

interneurons

What type of neuron, found within the CNS, performs the job of information processing? -bipolar neurons -sensory (afferent) neurons -interneurons (association neurons) -motor (efferent) neurons

interneurons (association neurons)

What type of ion channel in neurons is always open? -regulated -local -active -leak

leak

Which of the following is the primary factor in the maintenance of a cell's negative charge during resting membrane potential? -voltage-gated channels -ligand-gated channels -leak channels -sodium-potassium pump

leak channels

Graded potentials: -produce an effect that spreads actively across the membrane surface. -may cause either depolarization or hyperpolarization. -produce an effect that increases with distance from the point of stimulation. -cause repolarization.

may cause etiher 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?

mechanically-gated

The most common type of neuron in the human body is: -multipolar. -unipolar. -bipolar. -pseudounipolar.

multipolar

Saltatory conduction is made possible by -large nerve fibers. -diphasic impulses. -the myelin sheath. -erratic transmission of nerve impulses.

myelin sheath

Determine the fiber type in which propagation of an action potential will occur most quickly. -type C fiber -unmyelinated type B fiber -myelinated type A fiber -myelinated type B fiber

myelinated type A fiber

The functional unit of the nervous system is the

neuron