A&P I - Section 11
There are _______ pairs of cranial nerves and __________ pairs of spinal nerves.
12; 31
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 Answer: D. all of the choices are correct
a person who has seizures might have a deficit of which of the following?
GABA
Voltage-gated sodium channels are sensitive to changes in the extracellular concentration of
calcium ions
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
the enteric nervous system consist of plexuses within the walls of the
digestive tract
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
a neuron is receiving a stimulus which gets stronger and stronger. The result is
frequency of occurrence of action potential increases
cell bodies of the peripheral nervous system are located in
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
a neuron within the central nervous system that carries action potentials from one neuron to another is called a(n) ____________
interneuron
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
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
viagara is used to treat erectile dysfunction by prolonging the effects of ________ on blood vessels.
nitric oxide (NO)
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
resting membrane potential close to its normal value
neurons arranged in a circular pathway form
reverberating circuits
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?
sattelite cells
a stimulus either causes an action potential or it doesn't. This is called
an all-or-none response
the junction of the neuron with another cell is a/an
synapse
In some cells, an afterpotential occurs because
there is prolonged, elevated permeability to potassium during repolarization
which of the following statements accurately describe 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
what is the only neurotransmitter released at the neuromuscular junction?
acetylcholine
identify the type of synapse that includes a presynaptic cell, synaptic cleft, and postsynaptic cell.
chemical
the peripheral nervous system includes the
cranial nerves
which of the following is mismatched?
microglia - provide support for the neuron cell body
the motor neurons responsible for making a fist are
multipolar
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
which of the following is mismatched?
somatic nervous system - sensory division of PNS
the central nervous system includes the
spinal cord
gray matter on the surface of the brain is/are called
the cortex
axons contain
the trigger zone