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
5, 3, 2, 4, 1
The nervous system
All choices are correct
The speed of an action potential depends upon
All of the choices are correct
. Which of the following statements regarding voltage-gated K+ channels is true?
All of these statements are true.
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
Check all that apply: Identify the mechanisms by which neuromodulators alter synaptic transmission.
Changing neurotransmitter receptor numbers; Affecting breakdown of neurotransmitters; Affecting the removal of neurotransmitters
Match the neuroglial cell with its function: Schwann cell
E. form myelin sheath around part of the axon in the PNS
Match the following concerning concentration differences across the plasma membrane: potassium ions
E. plasma membrane is more permeable to this ion because of leak ion channels
Match the term with the correct definition: repolarization
E. return to the resting membrane potential
Gray matter consists of bundles of myelinated axons
FALSE
. A person who has seizures might have a deficit of which of the following?
GABA
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
Match the neuronal pathways and circuits with the correct definition: Oscillating (reverberating) circuit
Important in functions that are periodically active such as the sleep/wake cycle and respiration.
In hyperpolarization
K+ ions tend to diffuse out of the cell
Which of the following statements regarding neuroglia is false?
Neuroglia produce action potentials for skeletal muscles
Identify structure "E" on the neuron
Node of Ranvier (farthest to the right)
Match the neuronal pathways and circuits with the correct definition: Convergent pathway
Pathways that allow different parts of the nervous system to affect the activity of a neuron
Match the neuronal pathways and circuits with the correct definition: Divergent pathway
Pathways that allow one part of the nervous system to affect more than one part of the nervous system.
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
Identify structure "D" on the neuron
Schwann cell (2nd from the right)
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
Gray matter has little myelination, whereas white matter has abundant myelination
TRUE
True or False: The nervous system and the endocrine system are the major control systems of the body.
TRUE
If five action potentials arrive at the same synapse in very close succession, which of the following would occur?
Temporal summation occurs.
Action potentials at a chemical synapse
travel from presynaptic terminal to presynaptic membrane
Axons contain
trigger zone
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?
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.
Which of the following is NOT true of reactive astrocytosis
causes the spread of inflammation
Protein synthesis in neurons occurs in
cell bodies or soma
The absolute refractory period assures
completion of repolarization before another action potential
autonomic nervous system
has two sets of neurons in a series
Check all that apply: Identify the functions of the nervous system.
controlling muscles and glands; integrating information; receiving sensory input
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.
____________ are processes that conduct electric signals toward the cell body.
dendrites
Identify structure "A" on the neuron
dendrites (farthest to the left)
The figure illustrates the Action Potential. What does "B" represent?
depolarization
Check all that apply: Identify the phases of an action potential.
depolarization; hyperpolarization; repolarization
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
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
When a neuron releases a neuromodulator that _____ the release of neurotransmitters from another neuron, this is called presynaptic facilitation.
facilitation
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
____________ are collections of neuron cell bodies located outside of the central nervous system.
ganglia
What inhibitory neurotransmitter is blocked in strychnine poisoning?
glycine
Mr. Miller has been hospitalized for the flu. The flu virus increases membrane permeability of 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 from to another is called a/an
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 the membrane potential
. A change in resting membrane potential confined to a small area is called a(n)
local potential
The figure illustrates the Action Potential. What does "A" represent
local potential
Worksheet Questions:
The division of the nervous system that transmits electrical impulses towards cardiac muscle, smooth muscle and glands is the autonomic nervous system; while the division of the nervous system that transmits electrical impulses towards skeletal muscle is the somatic nervous system.
Worksheet Questions
The division of the peripheral nervous system that transmits electrical impulses from sensory receptors to the CNS is the afferent division, while the afferent division of the peripheral nervous system transmits electrical impulses from the CNS toward muscles and glands.
. Rapid removal or destruction of neurotransmitter in the synaptic cleft
may affect the ability of the postsynaptic membrane to generate action potentials
____________ are neuroglia cells that are macrophages
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.
Which of the following is true?
The resting membrane potential is proportional to the tendency for K+ to diffuse out of the cell
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
Identify structure "B" on the neuron
neuron cell body (soma)(2nd from the left)
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
Action potentials are conducted rapidly from one node of Ranvier to the next in a process called ____________ conduction
saltatory
The nervous system has two subdivisions - the central nervous system and the ____________ nervous system.
peripheral
The figure is a process figure of the chemical synapse. What does "E" represent?
postsynaptic membrane
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
The figure is a process figure of the chemical synapse. What does "C" represent?
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
Check all that apply: Identify the characteristics of action potentials.
The strength of the stimulus determines the frequency of the action potentials; They are all-or-none; They are propagated in a non-decremental fashion.
The figure illustrates the Action Potential. What does "C" represent?
repolarization
What type of neuroglial cells provide support and nutrition to sensory ganglia in the PNS?
satellite cells
Which of the following is NOT a neuroglia of the CNS
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
Which of the following will lead to depolarization
an increase in K+ ions in the extracellular fluid
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
Identify structure "C" on the neuron.
axon (middle)
Nerve fibers are also called ____________.
axons
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 of Na+
Which of the following is mismatched?
somatic nervous system - sensory division of PNS
The junction of a neuron with another cell is a/an
synapse
The figure is a process figure of the chemical synapse. What does "D" represent?
synaptic cleft
The figure is a process figure of the chemical synapse. What does "B" represent?
synaptic vesicle
The figure is a process figure of the chemical synapse. What does "A" represent?
voltage-gated calcium channel
In some cells, an afterpotential occurs because
there is prolonged, elevated permeability to potassium during repolarization
Which of the following is NOT true about astrocytes
they can aid in the regeneration of injured neurons
In order for local potentials to trigger an action potential, the membrane must reach a level called the ______.
threshold
The figure illustrates the Action Potential. What does "D" represent?
threshold
The motor (efferent) division of the peripheral nervous system
transmits impulses from the CNS to skeletal muscle
Receptor molecules in synapses
. have a high degree of specificity
In an EPSP (excitatory postsynaptic potential), there is a
. local depolarization
Which of the following statements accurately describes events that occur as a result of a local potential reaching threshold
A positive feedback cycle develops in which depolarization causes activation gates of Na+ ion channels to open
Match the term with the correct definition: Local Potential
A. a small change in the resting membrane potential confined to a small area
Match the following concerning concentration differences across the plasma membrane: higher inside cell
A. concentration of potassium
Match the neuroglial cell with its function: astrocytes
A. influence function of blood-brain barrier
Which of the following is mismatched
A. microglia - provide support for the neuron cell body
. Neurotransmitter is being released at a synapse. Which of the following occurs last?
An action potential is produced in the postsynaptic membrane.
Which of the following events is NOT a characteristic of an action potential
As sodium ions enter, the inside of the plasma membrane becomes more negative.
Match the term with the correct definition: Resting Membrane Potential
B. a charge difference across the plasma membrane when the cell is in an unstimulated state
Match the following concerning concentration differences across the plasma membrane: higher outside cell
B. concentration of sodium and chloride
Match the neuroglial cell with its function: microglia
B. macrophages in CNS
Match the term with the correct definition: Action Potential
C. a larger change in resting membrane potential that spreads over entire surface of a cell
Match the following concerning concentration differences across the plasma membrane: large molecules trapped inside cell
C. negatively charged proteins
Match the neuroglial cell with its function: ependymal cells
C. produce cerebrospinal fluid
Match the neuroglial cell with its function: oligodendrocyte
D. form myelin sheath around axons in CNS
Match the term with the correct definition: depolarization
D. membrane becomes more positive when sodium ions diffuse into cell
Match the following concerning concentration differences across the plasma membrane: requires ATP
D. sodium/potassium pump
Which of the following situations occurs in electrically excitable cells?
Depolarization causes voltage-gated sodium ion channels to open.
Which of the following is true?
Unmyelinated axons rest in invaginations of Schwann cells or oligodendrocytes
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
The figure illustrates the Action Potential. What does "E" represent?
afterpotential
Which of the following is responsible for problem-solving skills?
central nervous system
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 action 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
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
Check All That Apply: Identify the two functional sub-divisions of the peripheral nervous system
motor division; sensory division
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
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
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/an
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.
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 chord
The junction between two neurons is a
synapse
Gray matter on the surface of the brain is 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.
The plasma membrane of a neuron is more permeable to potassium ions because
there are more leak ion channels for K+ than NA+
Nervous tissue of the CNS that is composed primarily of myelinated axons is often referred to as ______ matter.
white
