Straighterline A&P Chapter 11
There are _____ pairs of cranial nerves and _____ pairs of spinal nerves.
12; 31
Arrange the events of synaptic transmission in correct sequence. (1) sodium ions diffuse into the cell and cause a local potential (2) neurotransmitter binds with receptor on postsynaptic cell (3) neurotransmitter diffuses across the synaptic cleft (4) membrane permeability to sodium ions on postsynaptic cell increases (5) action potential causes release of neurotransmitter
5, 3, 2, 4, 1
Each voltage-gated Na+ ion channel has two voltage sensitive gates: an activation gate and an inactivation gate. Which of the following would occur during depolarization?
Both activation and inactivation gates are open
The nervous system A. monitors internal and external stimuli. B. transmits information in the form of action potentials. C. interprets or assesses information. D. maintains homeostasis. E. All of these choices are correct.
E. All of these choices are correct.
Which of the following statements regarding voltage-gated K+ channels is true? A. These channels have only one gate. B. These channels open more slowly than Na+ channels. C. Once open, these channels remain open until repolarization is complete. D. These channels are specific for potassium. E. All of these statements are true.
E. All of these statements are true.
____________ are collections of neuron cell bodies located outside of the central nervous system.
Ganglia
Identify the statement that best differentiates gray matter and white matter.
Gray matter consists of cell bodies and dendrites whereas white matter consists mostly of myelinated axons
In hyperpolarization
K+ ions tend to diffuse out of the cell.
____________ are neuroglia cells that are macrophages.
Microglia
Identify the correct sequence of information in a chemical synapse.
Presynaptic terminal; synaptic cleft; postsynaptic membrane
Why isn't an action potential transmitted from a postsynaptic membrane to a presynaptic terminal?
Presynaptic terminals have no acetylcholine receptors.
form myelin sheath around part of the axon in the PNS
Schwann cell
Schwann cells differ from oligodendrocytes in which of the following ways?
Schwann cells form a myelin sheath around a portion of only one axon, while oligodendrocytes can surround portions of several axons.
Action potentials at a chemical synapse
travel from presynaptic terminal to presynaptic membrane.
A change in the resting membrane potential has the following characteristics (non- propagated, graded, can summate). This type of change can
be a local potential and a consequence of an increase in the permeability to Na+.
Neurons that have a single axon and a single dendrite are
bipolar
A local anesthetic such as Novocaine decreases membrane permeability to Na+ ions. The use of this anesthetic will
block sensory input into the CNS
The strength of a stimulus is communicated through
both the frequency and the length of time action potentials are produced
The function of acetylcholinesterase is to
breakdown acetylcholine in the synapse.
White matter is composed of
bundles of myelinated axons
What ion is necessary for the release of neurotransmitter from synaptic vesicles? A. chloride
calcium
Voltage-gated sodium channels are sensitive to changes in the extracellular concentration of
calcium ions
Neurotransmitters
cause the production of action potentials in the postsynaptic membrane.
Protein synthesis in neurons occurs in
cell bodies or soma
The absolute refractory period assures
completion of repolarization before another action potential.
The autonomic nervous system
has two sets of neurons in a series
higher inside cell
concentration of potassium
higher outside cell
concentration of sodium and chloride
When two or more presynaptic neurons synapse with a single postsynaptic neuron in the CNS, a(n) _______ pathway is formed.
convergent
Axons
have a distal portion that branches to form the presynaptic terminals.
Receptor molecules in synapses
have a high degree of specificity.
Pathways that allow different parts of the nervous system to affect the activity of a neuron.
convergent pathway
membrane becomes more positive when sodium ions diffuse into cell
depolarization
Receptor molecules
determine whether a neurotransmitter will be excitatory or inhibitory.
The enteric nervous system consists of plexuses within the walls of the
digestive tract
Sensory neurons carrying action potentials from pain receptors synapse within the spinal cord with interneurons. These interneurons synapse with motor neurons leading back to an effector and ascending neurons that carry action potentials toward the brain. This is an example of a(n) _____ pathway.
divergent
Pathways that allow one part of the nervous system to affect more than one part of the nervous system.
divergent pathway
An inhibitory postsynaptic potential (IPSP) can result from the
either influx of chloride or outflow of potassium ions.
Gap junctions are functional __________ synapses.
electrical
Synapses in which gap junctions allow ions to diffuse quickly from cell to cell are called ______ synapses.
electrical
Monamine oxidase inhibitors (MAO inhibitors)
enhance the binding of norepinephrine to its receptors.
Cerebrospinal fluid is produced by ____________ cells.
ependymal
Hydrocephaly is a condition whereby cerebrospinal fluid accumulates around the brain. What supportive cells continue CSF production despite it backing up in the subarachnoid space?
ependymal cells
produce cerebrospinal fluid
ependymal cells
A neuron is receiving a stimulus which gets stronger and stronger. The result is
frequency of occurrence of action potentials increases.
Action potentials are conducted more rapidly when transmission is
from node to node on a myelinated axon
Cell bodies of the peripheral nervous system are located in
ganglia
Groups of related nerve cell bodies located outside of the central nervous system are called _____.
ganglia
What inhibitory neurotransmitter is blocked in strychnine poisoning?
glycine
Mr. Miller has been hospitalized for the flu. The flu virus increases membrane permeability to potassium. You would expect his cells to
hyperpolarize
An IPSP is inhibitory because it
hyperpolarizes the postsynaptic membrane
The absolute refractory period ends when
inactivation gates of voltage-gated Na+ ion channels reopen.
When a neuron releases a neuromodulator that _____ the release of neurotransmitters from another neuron, this is called presynaptic facilitation.
increases
A local potential
increases or decreases in direct proportion to the stimulus strength.
Local hyperpolarization in a synapse is called a(an)
inhibitory postsynaptic potential.
Damage to a postsynaptic membrane would
interfere with the ability to respond to neurotransmitter.
A neuron within the central nervous system that carries action potentials from one neuron to another is called a(n)____________.
interneuron
A neuromodulator
is a substance released from neurons that influences the sensitivity of neurons to neurotransmitters.
The opening of more and more Na+ ion channels during depolarization
is an example of a positive feedback cycle
During the absolute refractory period, the cell
is insensitive to further stimulation
The central nervous system
is the site for processing information
For the resting membrane potential, increasing the sodium ion concentration in the ECF results in
little change in membrane potential
In an EPSP (excitatory postsynaptic potential), there is a
local depolarization
A change in resting membrane potential confined to a small area is called a(n) A. local potential.
local potential
a small change in the resting membrane potential confined to a small area
local potential
Rapid removal or destruction of neurotransmitter in the synaptic cleft
may affect the ability of the postsynaptic membrane to generate action potentials.
macrophages in CNS
microglia
The same neurotransmitter binds to a postsynaptic cell but produces a variety of different effects. What does this mean?
The postsynaptic cell is expressing different types of receptors for the same neurotransmitter.
large molecules trapped inside cell
negatively charged proteins
If you cut bundles of axons and their myelin sheaths in the PNS, you cut
nerves
Compounds classified as ______ alter synaptic transmission by changing neurotransmitter receptor numbers or affecting the breakdown and/or removal of neurotransmitter.
neuromodulators
Viagra is used to treat erectile dysfunction by prolonging the effects of _____ on blood vessels.
nitric oxide (NO)
Gaps or interruptions in the myelin sheath are called
nodes of Ranvier
Clusters of gray matter deep within the brain are called
nuclei
Neurons arranged in a circular pathway form
reverberating circuits
The nervous system has two subdivisions - the central nervous system and the ____________ nervous system.
peripheral
potassium ions
plasma membrane is more permeable to this ion because of leak ion channels
Low levels of ___ can have dire consequences on the functioning of neurons because of its role in membrane repolarization.
potassium ions
Neurotransmitters are released from the
presynaptic terminal
Synaptic vesicles contain neurotransmitters and are present in the
presynaptic terminals
The blood brain barrier
protects neurons from toxic substances in the blood.
Neurons in the skin that are responsible for detecting pain are
pseudo-unipolar
A decrease in the number of voltage-gated Ca2+ ion channels in the presynaptic terminal would
reduce or inhibit transmission across the synapse
return to resting membrane potential
repolarization
a charge difference across the plasma membrane when the cell is in an unstimulated state
resting membrane potential
Action potentials are conducted rapidly from one node of Ranvier to the next in a process called ____________ conduction.
saltatory
What type of neuroglial cells provide support and nutrition to sensory ganglia in the PNS?
satellite cells
Most unipolar neurons are ____________ neurons.
sensory
Saltatory conduction of an action potential means that
an action potential is conducted from one node of Ranvier to the next node.
A stimulus either causes an action potential or it doesn't. This is called
an all or none response
When a neurotransmitter binds to its receptor and increases the permeability of the postsynaptic membrane to sodium ions,
an excitatory postsynaptic potential (EPSP) will result.
Dendrites
are the input part of the neuron
Nissl bodies are
areas of rough endoplasmic reticulum.
LouAnn is being treated for a neurological condition with a specific drug that target neurons deep within the brain. Which glial cell must be bypassed by this drug in order for it to be effective?
astrocyte
influence function of blood-brain barrier
astrocytes
The division of the nervous system that transmits electrical impulses towards cardiac muscle, smooth muscle and glands is the __________ nervous system; while the division of the nervous system that transmits electrical impulses towards skeletal muscle is the ___________ nervous system.
autonomic; somatic
Nerve fibers are also called ____________.
axons
The plasma membrane of a neuron is more permeable to potassium ions because
there are more leak ion channels for K+ than Na+.
In some cells, an afterpotential occurs because
there is prolonged, elevated permeability to potassium during repolarization.
In order for local potentials to trigger an action potential, the membrane must reach a level called the ______.
threshold
The motor (efferent) division of the peripheral nervous system
transmits impulses from the CNS to skeletal muscle.
A person who has seizures might have a deficit of which of the following? A. GABA B. dopamine C. glutamate D. serotonin E. histamine
A. GABA
Which of the following is true? A. Unmyelinated axons rest in invaginations of Schwann cells or oligodendrocytes.. B. Myelination will not influence the speed of conduction of action potentials. C. The myelin sheath inhibits the flow of electrical charges at nodes. D. The myelin sheath is a protein wrapping. E. The myelin sheath does not electrically insulate the axons from one another.
A. Unmyelinated axons rest in invaginations of Schwann cells or oligodendrocytes..
Which of the following events will lead to depolarization? A. an increase in K+ ions in the extracellular fluid B. a decrease in K+ ions in the extracellular fluid C. an increase in the rate of diffusion of K+ ions from cells D. an increase in Na+ ions in the extracellular fluid E. None of these events would cause depolarization.
A. an increase in K+ ions in the extracellular fluid
Which of the following is responsible for problem-solving skills? A. central nervous system B. peripheral nervous system C. somatic nervous system D. autonomic nervous system E. None of these choices is correct.
A. central nervous system
Which of the following is mismatched? A. microglia - provide support for the neuron cell body B. astrocytes - blood-brain barrier C. oligodendrocytes - form myelin sheaths D. ependymal cells - produce cerebrospinal fluid E. ependymal cells - choroid plexus
A. microglia - provide support for the neuron cell body
Which of the following events is NOT a characteristic of an action potential? A. The plasma membrane becomes highly permeable to sodium ions and depolarization results. B. As sodium ions enter, the inside of the plasma membrane becomes more negative. C. At the peak of depolarization, sodium channels begin to close and potassium channels open. D. In repolarization, potassium ions flow out of the cell. E. Action potentials occur according to the all-or-none principle.
B. As sodium ions enter, the inside of the plasma membrane becomes more negative.
Which of the following is NOT a neuroglia of the CNS? A. ependymal cells B. satellite cells C. oligodendrocytes D. astrocytes
B. satellite cells
Which of the following statements accurately describe events that occur as a result of a local potential reaching threshold? A. Activation gates of Na+ ion channels begin to close. B. Inactivation gates of Na+ ion channels begin to open. C. A positive feedback cycle develops in which depolarization causes activation gates of Na+ ion channels to open. D. K+ ion channels begin to close. E. Inactivation gates of Na+ ion channels begin to open and a positive feedback cycle develops in which depolarization causes activation gates of Na+ ion channels to open.
C. A positive feedback cycle develops in which depolarization causes activation gates of Na+ ion channels to open.
Neurotransmitter is being released at a synapse. Which of the following occurs last? A. Calcium ions enter the presynaptic terminal. B. Synaptic vesicles release neurotransmitter by exocytosis. C. An action potential is produced in the postsynaptic membrane. D. Neurotransmitter flows rapidly across the synaptic cleft. E. Neurotransmitter binds with the receptor on the postsynaptic membrane.
C. An action potential is produced in the postsynaptic membrane.
Which of the following situations occurs in electrically excitable cells? A. When Na+ ion channels open, K+ ion channels close. B. The sodium-potassium exchange pump moves sodium into the cell. C. Depolarization causes voltage-gated sodium ion channels to open. D. Ligand-gated sodium ion channels are opened by high extracellular calcium levels. E. Proteins tend to diffuse out of the cell.
C. Depolarization causes voltage-gated sodium ion channels to open.
Which of the following statements regarding neuroglia is false? A. Neuroglia serve as the major supporting tissue in the CNS. B. Neuroglia form part of the blood-brain barrier. C. Neuroglia produce action potentials for skeletal muscles. D. Neuroglia form myelin sheaths around some axons. E. Neuroglia produce cerebrospinal fluid.
C. Neuroglia produce action potentials for skeletal muscles.
Which of the following is true? A. The resting plasma membrane is more permeable to Na+ than K+. B. The resting membrane potential never reaches an equilibrium point. C. The resting membrane potential is proportional to the tendency for K+ to diffuse out of the cell. D. Negatively charged Cl- ions are attracted by negative charges in the cell. E. The purpose of the sodium-potassium exchange pump is to create an equilibrium of ion concentrations.
C. The resting membrane potential is proportional to the tendency for K+ to diffuse out of the cell.
Which of the following is NOT true of reactive astrocytosis? A. injury site is blocked off B. scars limit regeneration C. causes the spread of inflammation D. reduces injury to surrounding tissue
C. causes the spread of inflammation
The speed of an action potential depends upon A. whether an axon is myelinated or not myelinated. B. thickness of the myelin sheath. C. the diameter of the axon. D. All of the choices are correct.
D. All of the choices are correct.
Which of the following is NOT true about astrocytes? A. They can wall off an injury site to prevent spread of inflammation. B. They can prevent toxic substances from entering brain tissue. C. They can release chemicals that promote formation of synapses. D. They can aid in the regeneration of injured neurons.
D. They can aid in the regeneration of injured neurons.
Which of the following is mismatched? A. central nervous system - brain B. autonomic nervous system - sympathetic and parasympathetic divisions C. peripheral nervous system - spinal nerves D. somatic nervous system - sensory division of PNS E. peripheral nervous system - sensory and motor divisions
D. somatic nervous system - sensory division of PNS
____________ are processes that conduct electric signals toward the cell body.
Dendrites
If the ECF around a nerve cell is replaced with an isotonic saline solution that contains potassium ions and other solutes at concentrations very close to the ECF concentrations of a normal cell, the result is
a resting membrane potential close to its normal value
What is the only neurotransmitter released at the neuromuscular junction?
acetylcholine
a larger change in resting membrane potential that spreads over entire surface of a cell
action potential
The division of the peripheral nervous system that transmits electrical impulses from sensory receptors to the CNS is the __________ division, while the ___________ division of the peripheral nervous system transmits electrical impulses from the CNS towards muscles and glands.
afferent; efferent
Identify the type of synapse that includes a presynaptic cell, synaptic cleft, and postsynaptic cell.
chemical
The respiratory center of the brain (taking into account input from chemoreceptors, pulmonary stretch receptors and higher centers of the brain to determine respiratory output) is an example of a ______ circuit.
converging
The sensory (afferent) division of the peripheral nervous system
conveys actions potentials to the CNS
The gray matter of the cerebrum is composed of neuron cell bodies and makes up both the ______ and the ______.
cortex ; deep cerebral nuclei
The peripheral nervous system includes the
cranial nerves
Enkephalins produce presynaptic inhibition in neurons transmitting pain signals. Increased levels of enkephalins will
decrease awareness of pain
Fran has a microbial infection attacking his brain. Which cell type would you expect to proliferate and be most active during this time?
microglial cells
A neuron with several dendrites and a single axon would be called a ____________ neuron.
multipolar
The motor neurons responsible for making a fist are
multipolar
An action potential
occurs when the local potential reaches threshold level
Multiple sclerosis is a neurological disorder in which myelin sheaths in the CNS are destroyed. Which of the following neuroglial cells is being damaged in multiple sclerosis?
oligodendrocyte
form myelin sheath around axons in CNS
oligodendrocyte
Continuous conduction of an action potential means that
one action potential stimulates the production of a new action potential at the adjacent site.
When repolarization of a neuron is complete, the
original polarity of the neuron is restored
Important in functions that are periodically active such as the sleep/wakecycleandrespiration.
oscillating/reverberating circuit
Which type of circuit is associated with complex neuronal processes, such as solving mathematical equations?
parallel after-discharge
Digestion of food is regulated by the
parasympathetic division of the ANS
A neuron that conducts pain sensations to the central nervous system would be classified as a(n)
sensory or afferent neuron
Depolarization of the nerve cell membrane occurs when there is a rapid influx (inflow) of
sodium ions
During depolarization of the plasma membrane,
sodium ions move rapidly into the cell.
requires ATP
sodium potassium pump
When two action potentials arrive simultaneously at two different presynaptic terminals that synapse with the same postsynaptic neuron,
spatial summation occurs
The central nervous system includes the
spinal cord
The junction between two neurons is a
synapse
The junction of a neuron with another cell is a(n)
synapse
If five action potentials arrive at the same synapse in very close succession, which of the following would occur?
temporal summation occurs
Gray matter on the surface of the brain is/are called
the cortex
If the charge difference across the plasma membrane is decreased,
the membrane potential is more positive
A series of local potentials causes the membrane potential to move to -80 mV. Predict the result.
the neuron is hyperpolarized
Suppose both excitatory and inhibitory neurons synapse with a single postsynaptic neuron. What determines if an action potential is initiated in the postsynaptic neuron?
the number of EPSPs in relation to the number of IPSPs
Chemical synapses are characterized by
the release of neurotransmitter by the presynaptic terminal.
Axons contain
the trigger zone
Nervous tissue of the CNS that is composed primarily of myelinated axons is often referred to as ______ matter.
white