Exam 48: Neurons, Synapses, and Signalling

Why are action potentials usually conducted in one direction?

Although the membrane of a "resting" neuron is highly permeable to potassium ions, its membrane potential does not exactly match the equilibrium potential for potassium because the neuronal membrane is also ________.

Which of the following will increase the speed of an action potential moving down an axon? I. Action potentials move faster in wider axons. II. Action potentials move faster in axons lacking potassium ion channels. III. Action potentials move faster in myelinated axons.

The fastest possible conduction velocity of action potentials is observed in ________.

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 common feature of action potentials is that they

A chemical that affects neuronal function but is not stored in presynaptic vesicles is ________.

The heart rate of a vertebrate will decrease in response to the arrival of ________.

In a resting potential, an example of a cation that is more abundant as a solute in the cytosol of a neuron than it is in the interstitial fluid outside the neuron is ________.

The membrane potential in which there is no net movement of the ion across the membrane is called the ________.

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?

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 depolarises 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?

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

Opening all of the sodium channels on an otherwise typical neuron, with all other ion channels closed (which is an admittedly artificial setting), should move its membrane potential to ________.

The "undershoot" phase of hyperpolarisation is due to ________.

The operation of the sodium-potassium pump moves ________.

Refer to the following graph of an action potential to answer the question. The neuronal membrane is at its resting potential at label ________.

Neurotransmitters can affect postsynaptic cells by ________. I. initiating signal transduction pathways in the cells II. causing molecular changes in the cells III. altering ion channel proteins IV. altering the permeability of the cells

After the depolarisation phase of an action potential, the resting potential is restored by ________.

Where are neurotransmitter receptors located?