Neuro Bio Test 1

During the overshoot phase of an action potential, membrane potential briefly reaches a value near __________ mV

+30

If the distribution of EPP amplitudes has peaks at 0.4 mV, 0.8 mV, 1.2 mV 1.6 mV and 2.0 mV, what is the most likely amplitude of the MEPP?

0.4 mV

What is the likely source of the quanta that make up the EPP?

Fusion of individual synaptic vesicles with the plasma membrane

How would the application of a Ca++ channel blocker affect the function of a synapse?

It would eliminate the postsynaptic potential and the presynaptic Ca++ current

Hodgkin and colleagues found which of the following ratios for relative permeability to ions during resting vs action potential

Resting potential Pk, Pna, Pcl= 1, 0.04, 0.45. Action potential Pk, Pna, Pcl = 1:20:.045

Which cell produces myelin in the nerves of the peripheral nervous system?

Schwann cells

Which evidence supports the assertion that the macroscopic Na + current is the sum of many microscopic Na+ currents?

The averaged collective response of single channels resembles the time course of the macroscopic current

Cerebrospinal fluid is found where?

Ventricles and subarchnoid space (b and c)

The pia mater is :

a basement membrane (lamina) generated by astrocytes

What is the function of microtubules in a neuron?

all of the above

Which characteristic is an accepted criterion for classifying a molecule as a neurotransmitter?

all of the above

Which conclusion can be drawn from hodkin and Huxeleys studies of K+ and Na+ conductances?

all of the above

In the knee jerk reflex, the afferent neurons

are sensory neurons

Amphetamines cause release of

catecholamines and seotonin

Which of the following parts of a neuron would be labeled by a nissl stain?

cell body

Ion channels that are involved in generation of action potentials open or close in response to

changes in voltage

Which structure can be found exclusively at an electrical synapse?

connexon

studies of the ionic basis of the action potential in a squid giant axon found that

decreasing sodium outside of the cell decreases the size of the action potential

The amplitude of the action potential of a given neuron is

dependent on the magnitude of the sensory stimulus

An action potential occurs if current injected into a neuron ____ the neuron to reach _______ potential

depolarizes; threshold

In which order are catecholamine neurotransmitters synthesized?

dopamine, norepinephrine, epinephrine

which statement accurately describes the expression of genes in the nervous system?

every gene in the human genome is expressed in the CNS

In the sequence of events in neurotransmission, which event occurs just after the action potential arrives and spreads depolarization at the presynaptic terminal?

influx of Ca++ into the presynaptic terminal

Which statement best describes the Nernst equation

it relates the equilibrium potential of an ion to its intra- and extracellular concentrations

How will a neuron respond to an injection of negative current?

it will become hyperpolarized

Which vesicles, loaded with neuropeptides, arrive in the presynaptic terminal via axonal transport?

large dense core vesicles

The voltage clamp method controls the ________ at any desired level

membrane potential

which glial cell type serve as a resident immune cell in the central nervous system?

microglia

In general, the CNS of vertebrates has what type of organization?

motor functions are predominantly ventral, while sensory functions are dorsal

Which component represents the peripheral nervous system?

nerve

In the spinal cord, white matter is found on the ______ while gray matter is found on the _________

outside; inside

Which of the following best describes the thalmus?

part of the forebrain, a central relay station for motor and sensory info

Subthreshold current injected into an axon flows ______ along the axon and _______ with distance from the site of injection

passively; decays

Which experimental model did Hodgkin and Katz use in their studies of the resting membrane potential?

squid giant neuron

Which of the following best describes the neural doctorine?

the nervous system is made up of discreet individual cells

Which statement regarding refractory periods is true?

the refractory period sets an upper limit on the frequency of action potentials

Which processes underlies the refractory period?

the slow time course of turning off the K+ conductance activation and the persistence of sodium conductance inactivation

Which of the following is true regarding graded potentials?

their amplitude is proportional to the magnitude of the triggering stimulus

Which statement about astrocytes is true?

they play a role in the formation of the blood-brain barier

Which function is a characteristic primarily of neurons only, and not glia?

transmits action potentials

True or false: interneurons are found only in the CNS?

true

What is the common precursor of all catecholamines?

tyrosine

What are the causes of membrane potential?

unequal distribution of ions across the membrane, and a plasma membrane selectively permeable to some ions more than others

EPSPs are most often triggered by changes in conductance for ____________, while IPSPs are most often triggered by changes in conductance for ____________.

Na+ and Ca++; K+ and Cl-

Which transporter plays a key role in maintaining the concentration gradients of ions in the brain that are ciritical for generating electrical signals?

Na+/K+, ATPase pump

Concentrations of which ion, inside and outside of a neuron, have the greatest effect on the resting membrane potential ?

Potassium K+