Week 2, Neurophysiology Flashcards
The all-or-none principle states that
all stimuli great enough to bring the membrane to threshold will produce identical action potentials.
________ open or close in response to binding specific molecules.
Chemically gated channels.
The fibre type in which propagation of an action potential will occur most quickly is,
myelinated type A fibre.
The ________ division of the peripheral nervous system brings sensory information to the central nervous system.
afferent
Rapid impulse conduction from “node” to “node” is called
saltatory propagation.
The minimum stimulus required to trigger an action potential is known as the,
threshold.
A shift of the resting transmembrane potential toward 0 mV is called;
depolarization.
The site of intercellular communication between a neuron and another cell is the,
synapse.
The period during which an excitable membrane can respond again, but only if the stimulus is greater than the threshold stimulus, is the ________ period.
relative refractory.
In what ways do the two divisions of the autonomic nervous system interact?
Answers:
One division may counterbalance the other division.
Occasionally only one division communicates with an organ.
Both divisions may work together for the function of an organ or a process.
One division may increase function of an organ, while the other division inhibits it.
All of the answers are correct.
All of the answers are correct.
All of the following are true of neural reflexes except that they
Answers:
are automatic motor responses.
are the simplest form of behavior.
help preserve homeostasis.
cannot be modified by the brain.
involve at least two neurons.
cannot be modified by the brain.
A neuron that receives neurotransmitter from another neuron is called
the postsynaptic neuron.
What triggers the release of acetylcholine from a synaptic terminal?
What triggers the release of acetylcholine from a synaptic terminal?
A postsynaptic neuron will have an excitatory postsynaptic potential (EPSP) when
chemically regulated sodium channels are open and sodium is diffusing into the cell.
A stimulus that changes a postsynaptic neuron’s membrane from resting potential to -85 mV is a(n) ________ stimulus.
inhibitory.
Voltage-gated channels are present,
on the soma of neurons.
b.
in the membrane that covers axons.
c.
on the surface of dendrites.
d.
at the motor end plate.
in the membrane that covers axons.
The ________ nervous system controls the skeletal muscles.
somatic
Which type of synapse is most common in the nervous system?
chemical.
Neurotransmitters are released into the
synaptic cleft.
The presence of ________ dramatically increases the speed at which an action potential moves along an axon.
myelin.
Sympathetic nerves
contains short preganglionic fibers and longer postganglionic fibers.
Any stimulus that opens a ________ ion channel will produce a graded potential.
Answers:
voltage-gated
chemically gated
sodium
mechanically gated
All of the answers are correct.
All of the answers are correct.
________ reflexes perform the simplest functions of the autonomic nervous system
somatic.
The neurotransmitter ACh is,
always excitatory when used in the synapses of the sympathetic nervous system.
