QUIZ 12
The equilibrium potential of sodium is
+66mV.
________ carry sensory information to the CNS.
afferent neurons
which of the following neurotransmitters are known to bind to G-protein coupled receptors?
all of these bind to G-protein coupled receptors
The ________ nervous system provides involuntary regulation of smooth muscle, cardiac muscle, and glandular activity.
autonomic
The plasma membrane of an axon is called the
axolemma
The site in the neuron where EPSPs and IPSPs are integrated is the
axon hillock
Raising the potassium ion concentration in the extracellular fluid surrounding a nerve cell will have what effect?
both depolarize it and decrease the magnitude of the potassium equilibrium potential
The structures labeled "1" are dendrites. Their membranes contain numerous chemically-gated ion channels.
both statements are true.
at a(n) ______ synapse, a neurotransmitter is released to stimulate the postsynaptic membrane
chemical
Branches that may occur along an axon are called
collaterals
which of the following can cause demyelination
demyelination can be caused by arsenic, diphtheria, multiple sclerosis and mercury
Opening of sodium channels in the axon membrane causes
depolarization
a shift of the resting transmembrane potential toward 0 mV is called
depolarization
a threshold stimulus is the
depolarization necessary to cause an action potential
________ carry motor information to peripheral effectors
efferent neurons
In a(n) ________ synapse, current flows directly between cells.
electrical
in the peripheral nervous system, schwann cells participate in the repair of damaged nerves by
forming a cellular cord that directs axonal growth
Which of the following is not a function of the neuroglia?
memory
in _______, activity at an axoaxonic synapse increases the amount of neurotransmitter released when an action potential arrives at the axon terminus
presynaptic facilitation
_______ nerves are nerves that connect to the spinal cord
spinal
________ nerves are nerves that connect to the spinal cord.
spinal
A neuron that receives neurotransmitter from another neuron is called
the postsynaptic neuron
which of the following statements about the action potential is false?
the rapid depolarization phase is caused by the entry of potassium ions
Neurons in which dendritic and axonal processes are continuous and the soma lies off to one side are called
unipolar
Deteriorating changes in the distal segment of an axon as a result of a break between it and the soma is called ________ degeneration.
wallerian
In one form of presynaptic inhibition the release of ________ inhibits the opening of voltage gated calcium channels in the axon terminus.
GABA
which neurotransmitter has a direct effect on opening chloride channels?
GABA
the largest and most numerous of the glial cells in the central nervous system are the
astrocytes
Voltage-gated channels are present
in the membrane that covers axons
Voltage-gated sodium channels have both an activation gate and a(n) ________ gate.
inactivation
which of the following is true about threshold for an action potential?
it is more positive than the resting membrane potential
Small, wandering cells that engulf cell debris and pathogens in the CNS are called
microglia
the most abundant class of neuron in the central nervous system is
multipolar
Which of the following neurotransmitters is a dissolved gas?
nitric oxide
Axons terminate in a series of fine extensions known as
telodendria
The minimum stimulus required to trigger an action potential is known as the
threshold