which of the following is not a function of astrocytes?
provide the defense for the CNS
which of the following choices below describes the ANS
motor fibers that conduct nerve impulses from the CNS to skeletal muscles
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 followings describes the nervous system intergrative function
analyzes sensory information stores information makes decisions
which of the followings is not characteristic of neurons?
they are mitotic
the period after an initial stimulus when a neuron is not sensitive to another stimulus is the
absoulute refractory period
collections of nerve cell bodies outside the central nervous system are called
ganglia
a neuron that has as its primary function the job of connecting other neurons is called an
association neuron
saltatory conduction is made possible by
the myelin sheath
which of the following is not a chemical class of neurotransmitters?
nucleic acid
select the correct statement regarding synapses
the synaptic cleft prevents an impulse from being transmitted directly from one neuron to antoher
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 neurotransmitters inhibits pain and is mimicked by morphine, heroin, and methadone
endorphin
which of the followings describes the excitatory postsynaptic potential
short distance depolarization
which of the followings is not a recognized structural classification for neurons
pseudopolar
the most abundant class of neuron in the central nervous system is
multipolar
the rabies virus travels to the CNS via
retrograde intraaxonal transport
sensory neurons of the PNS are
unipolar
which of the following is not involved in creating the resting potential of a neuron
membrane permeability for sodium ions greater that potassium ions
the following are the main steps in the generation of an action potential.
1. sodium channels are inactivated
2. voltage-gated potassium channels open and potassium moves out of the cell, initiating repolarization.
3.sodium channels regain their normal properties.
4.a graded depolarization brings an area of an excitable membrane to threshold.
5.a temporary hyperpolarization occurs.
6.sodium channel activation occurs.
7. sodium ions enter the cell and depolarization occurs.
d.4,6,,7,1,2,3,5.
in the process of continuous action potential propagation,
a, b, and c
which of the following types of nerve fiber possesses the fastest speed of impulse propagation
type A
which of the following does not influence the time necessary for a nerve impulse to be transmitted
whether or not the impulse begins in the CNS