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chapter 11 fundamentals of the nervous system and tissue

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Which of the following is not a function of astrocytes?
Provide the defense for CNS
which of the choices below describes the ANS?
motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands
what are ciliated CNS neuroglia that play an active rold in moving the cerebrospinal fluid called?
ependymal cells
what does the central nervous system use to determine the strength of a stimulus?
frequency of action potentials
bipolar neurons are commonly____.
found in the retina of the eye
which of the following is and excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle?
acetylcholine
Which of the following describes the nervous system intergrative function?
analyses sensory information, stores information, makes decisions
the period after an intial stimulus when a neuron is not sensitive to another sitmulus is the__________.
absolute refractory period
which of the follwoing is not characteristic of neurons?
They are mitotic
the part of a neuron that conducts impulses away from its cell body is called a(n)______.
axon
which ion channel opens in respnse to a change in membrane potential and participates in the generation and conduction of action potentials?
voltage-gated channel
an impulse from one nerver cell is communicated to another nerve cell via the_____.
synapse
what is the role of acetylcholinesterase?
destroy ACh a brief period after its release by the axon endings
which of the following is not a function of the autonomic nervous system?
innervation of skeletal muscle
collections of nerve cell bodies outside the central nervous system are called______.
ganglia
the term central nervous system refers to the ___________.
brain and spinal cord
the substance released at axon terminals to propagate a nervous impulse is called a(n)_____.
neurotransmitter
a neuron that has as its primary function the job of connecting other neurons is called a(n)______.
association neuron(interneuron)
saltatory conduction is made possible by_________.
the myelin sheath
which of the following is not a chemical class of neurotransmitters?
nucleic acid
what is the correct statement regarding synapses?
neurotransmitter receptors are located on the axon terminals of cells
which of the following correctly describes a graded potential?
voltage stimulus to initate
Schwann Cells are functionally similar to...
oligodendrocytes
immediately after and action potential has peaked, which cellular gates open?
potassium
an inhibitory postsynaptic potential (IPSP) is associated with________.
hyperpolarization
when a sensory neuron is excited by some form of energy, the resulting graded potential is called a(n)_______.
generator potential
which of the following is not true of graded potentials?
they increase amplitude as they move away from the stimulus point.
which of the following is true about the movement of ions across excitable living membranes?
sodium gates in the membrane can open in response to electrical potential changes.
a second nerve impulser cannot be generated until_____.
the membrane potential has been re-established
in what way do the interior surface of a cell membrane of a resting (nonconducting) neuron differ from the external environment
the interior is negatively charged and contains less sodium
If a motor neuron in the body were stimulated by an electrode placed about midpoint along the length of the axon ________.
the impulse would spread bidirectionally
Which of the following neurotransmitters inhibits pain and is mimicked by morphine, heroin, and methadone?
endorphin
Which of the following describes the excitatory postsynaptic potential?
short distance depolarization
All of the following are neuroglial cells
except: ______________.
perikaryons
Chromatophilic substance is found
in the neuronal cell bodies
Terminal boutons are found ___________.
in the neuronal axons
Myelin sheaths in the CNS are produced by the
oligodendrocytes
Neuroglial cells that line the ventricles of the brain are the ______.
ependymal cells
A change in membrane potential from
-70 mV to -40 mV would be termed
depolarization
At rest, a cell will have more ______ ions in the cytoplasm than outside the cell.
potassium
During membrane repolarization, there is a decrease in the membrane permeability to which ion?
Sodium
A membrane maintains its resting potential mainly due to _________.
the sodium-potassium pump
The space between the presynaptic and postsynaptic membranes is called the __________.
synaptic cleft
The presynaptic neuron releases neurotransmitters in response to an influx of _______ ions.
calcium
IPSPs cause the postsynaptic membrane to become more permeable to ________.
potassium
__________ has occurred when a neuron is stimulated by more than one terminal.
Spatial summation
Generation of an action potential can be inhibited by all of the following except: ___________.
depolarization
Which of the following is not a functional class of neurotransmitters?
Biogenic amines
The natural opiates of our body are the: _______.
endorphins
A neuronal circuit where incoming information is spread around or amplified is ________.
diverging
All of the following are found in the PNS
except: _________.
microglia
Which class of neuron is rare in the human body and found in some special sensory organs?
Bipolar
The nodes of Ranvier are found _______.
on myelinated axons
All of the following are true of action potentials except: ______________.
they travel more slowly on myelinated
fibers
Neurotransmitters are removed from the synaptic cleft by all of the following except: ___________.
presynaptic inhibition
Which of the following is false or incorrect?
A nerve impulse occurs if the excitatory and inhibitory effects are equal