Exam 6: Neuronal Signaling and the Structure of the Nervous System

SNARE receptor protein complexes in presynaptic neurons function as inhibitors of calcium transport to dampen or reduce the amount of neurotransmitter vesicles which participate in exocytosis.

Which of the following is not true about axon transport?

The efferent division of the peripheral nervous system consists of the somatic nervous system and the autonomic nervous system.

The resting membrane potential

Which of the following statements concerning the rate of action potential propagation is true?

An increase in the extracellular concentration of K⁺ above normal would result in

The significance of the initial segment of axons is that

Neuron X makes inhibitory axon-axon synaptic contact with neuron Y at the synapse of Y and neuron Z.Stimulation of action potentials in X

Which of the following statements regarding neurotransmitters is true?

For an action potential to occur,

The central nervous system includes the

An action potential in a neuronal membrane differs from a graded potential in that

"Dual innervation of effectors" refers to the innervation of the same effector organs by somatic and autonomic nerves.

The major known classes of neurotransmitters and/or neuromodulators include each of the following except

Which of the following statements about norepinephrine is not correct?

The thalamus is the single most important control area for regulating the internal environment.

Opioid drugs,such as morphine,are agonists of a class of neurotransmitters called endorphins.

The frequency of action potentials in a postsynaptic cell is directly related to the degree of postsynaptic depolarization of the cell.

Drug X interferes with the action of norepinephrine at synapses.Which of the following mechanisms would not explain the effects of X?

A postsynaptic neuron has three presynaptic inputs - from neurons X,Y and Z.When X and Y are stimulated simultaneously and repeatedly,the postsynaptic neuron reaches threshold and undergoes an action potential.When X and Z are stimulated simultaneously,however,there is no change in the membrane potential of the postsynaptic neuron.What can you tell about presynaptic neurons Y and Z?