Exam 48: Neurons, Synapses, and Signaling

How could you increase the magnitude of excitatory postsynaptic potentials (EPSPs) generated at a synapse?

Use the information in the table to answer the question. Calculate the equilibrium potential for sodium. Assume a temperature of 37°C.

In multiple sclerosis, the myelin sheaths around the axons of the brain and spinal cord are damaged and demyelination results. How does this disease manifest at the level of the action potential? I.Action potentials move in the opposite direction on the axon. II.Action potentials move more slowly along the axon. III.No action potentials are transmitted.

If excitatory postsynaptic potentials (EPSPs) are produced nearly simultaneously through two different synapses on the same postsynaptic neuron, the EPSPs can also add together creating ________.

A researcher uses the chemical inhibitor cyanide to reduce ATP production in a neuron. What would be one effect of preventing ATP production?

Action potentials are normally carried in only one direction: from the axon hillock toward the axon terminals. If you experimentally depolarize the middle of the axon to threshold, using an electronic probe, then ________.

Refer to the following graph of an action potential to answer the question. The membrane's permeability to sodium ions is greatest at label ________.

At the neuromuscular junction, the neurotransmitter acetylcholine (ACh) is degraded by acetylcholinesterase. If a neurophysiologist applies the naturally occurring acetylcholinesterase inhibitor, onchidal (produced by the mollusc Onchidella binneyi), to a synapse, what would you expect to happen?

Which of the following is the most direct result of depolarizing the presynaptic membrane of an axon terminal?

The following steps refer to various stages in transmission at a chemical synapse. 1) Neurotransmitter binds with receptors associated with the postsynaptic membrane. 2) Calcium ions rush into neuron's cytoplasm. 3) An action potential depolarizes the membrane of the presynaptic axon terminal. 4) The ligand-gated ion channels open. 5) The synaptic vesicles release neurotransmitter into the synaptic cleft. Which sequence of events is correct?

An inhibitory postsynaptic potential (IPSP) occurs in a membrane made more permeable to ________.

If you experimentally increase the concentration of K⁺ inside a cell while maintaining other ion concentrations as they were, what would happen to the cell's membrane potential?

For a neuron with an initial membrane potential at -70 mV, an increase in the movement of potassium ions out of that neuron's cytoplasm would result in the ________.

Neurotransmitters are released from axon terminals via ________.

Refer to the following graph of an action potential to answer the question. The membrane potential is closest to the equilibrium potential for potassium at label ________.

The concentrations of ions are very different inside and outside a nerve cell due to ________.

Use the information in the table to answer the question. Calculate the equilibrium potential for potassium. Assume a temperature of 37°C.

Acetylcholine released into the junction between a motor neuron and a skeletal muscle binds to a sodium/potassium channel and opens it. This is an example of ________.

Why are action potentials usually conducted in one direction?

The botulinum toxin, which causes botulism, reduces the synaptic release of ________.