BIO 264 Module 6 Quiz 11-12

A

Rapid removal or destruction of neurotransmitter in the synaptic cleft ___________. A) may affect the ability of the postsynaptic membrane to generate action potentials. B) generates local potentials in the presynaptic terminal. C) is necessary for synaptic transmission. D) may lead to action potentials. E) may stop exocytosis.

Presynaptic axon terminals

Reflects the location of the synaptic vesicles containing neurotransmitters.

IPSP

Results in hyperpolarization of the postsynaptic membrane.

opening and closing ion channels

Role of neurotransmitter

Presynaptic terminal

The location from which neurotransmitters are released.

A

What might occur when multiple action potentials arrive in close succession at the same postsynaptic neuron via the same presynaptic terminal (i.e. the action potentials traveled down the same neuron)? A) Temporal summation may occur. B) Spatial summation may occur. C) Hyperpolarization occurs regardless of the whether the action potentials are excitatory or inhibitory. D) Depolarization occurs regardless of whether the action potentials are excitatory or inhibitory.

B

What might occur when two action potentials arrive simultaneously at the same postsynaptic neuron via two different presynaptic terminals (i.e. the action potentials traveled down two different neurons)? A) Temporal summation may occur. B) Spatial summation may occur. C) Hyperpolarization occurs regardless of the whether the action potentials are excitatory or inhibitory. D) Depolarization occurs regardless of whether the action potentials are excitatory or inhibitory.

efferent neurons

What type of neuron acts as a motor neuron by sending signals to the effector tissues?

spatial summation

increased recruitment of dendrites receiving action potentials

chemical synapse

the junction between two neurons

D

If both an excitatory and an inhibitory neuron synapsed with the same postsynaptic neuron, what would ultimately determine whether an EPSP were initiated or not? A) The type of postsynaptic neuron (i.e. multipolar, bipolar, or unipolar). B) The diameter of the postsynaptic neuron C) The myelination status of the neuron. Myelinated neurons tend to carry EPSPs whereas non-myelinated neurons D) The number of EPSPs compared to the number of IPSPs that reach the synapse

5 3 2 4 1

Each of the processes listed below occurs during the synaptic transmission of an EPSP. Rearrange these processes in the correct order in which they occur. 1. Sodium ions diffuse into the postsynaptic cell and stimulate an EPSP in the postsynaptic neuron 2. A neurotransmitter binds with a specific receptor on the postsynaptic cell 3. A neurotransmitter travels across the synaptic cleft 4. Postsynaptic cell membrane permeability to sodium ions increases 5. An action potential stimulates the release of a neurotransmitter into the synaptic cleft

cardiac muscle cells

Example of an electrical synapse

D

What would happen if the number of voltage-gated Ca++ ion channels in the presynaptic terminal were decreased? A) The transmission of both EPSPs and IPSPs across the synapse would be greatly decreased. B) The exocytosis of neurotransmitter-containing vesicles would be reduced or inhibited entirely which would always have an inhibitory effect on the transmission of action potentials across the synapse. C) This would have no effect whatsoever on the transmission of action potentials across the synapse. D) a and b are TRUE

B

What would happen if the number of voltage-gated Ca++ ion channels in the presynaptic terminal were decreased? A) The transmission of both EPSPs and IPSPs across the synapse would be greatly enhanced. B) The exocytosis of neurotransmitter-containing vesicles would be reduced or inhibited entirely which would have an inhibitory effect on the transmission of action potentials across the synapse. C) This would have no effect whatsoever on the transmission of action potentials across the synapse. D) Receptors on the postsynaptic membrane would be unable to bind to neurotransmitter molecules, due to decreased calcium levels within the synapse.

interneurons

Which neuron types is responsible for transporting messages between different neurons?

C

Which of the following are TRUE about chemical that trigger action potentials within postsynaptic cells? A) Called hormones and tend to cause EPSPs. B) called neuromodulators and always causes IPSPs. C) called neurotransmitters and may cause IPSPs or EPSPs. D) called Na+ ions and have no effect on IPSPs or EPSPs.

B

Which of the following are capable of inhibiting neurotransmitter secretion? A) Causing repolarization of the presynaptic terminal. B) Blocking Ca++ channels in the presynaptic terminal. C) Inhibiting repolarization of the presynaptic terminal. D) Blocking neurotransmitter receptors located within the postsynaptic membrane

C

Which of the following events would occur if a neurotransmitter bound to its receptor and increased sodium ion permeability of the postsynaptic membrane? A) The postsynaptic membrane would experience hyperpolarization. B) Chloride ion channels would open and chloride ions would diffuse into the cell. C) Postsynaptic membrane potential would likely exceed threshold, stimulating an EPSP. D) The postsynaptic membrane would become completely impermeable to potassium. E) Sodium ions would diffuse out of the postsynaptic membrane in accordance with their concentration gradient

B

Which of the following voltage changes correctly reflects that caused by an EPSP within a neuron? A) a change in voltage from 0 mV to +0.35 mV B) a change in voltage from -70 mV to -69.5 mV C) a change in voltage from -69.5 mV to -70 mV D) a change in voltage from +35 mV to 0 mV E) a change in voltage from -70 mV to -70.5 mV