Chemical Basis of Neural Signaling

Comprehensive practice questions covering Chapter 7: Chemical Basis of Neural Signaling, including synapse types, vesicle cycles, and postsynaptic signaling.

How is an action potential described in the context of neural signaling?

It is an electrochemical signal.

What is the definition of synaptic transmission?

The process by which information conveyed by the electrical signal of a neuron is passed to another cell.

What structures facilitate the direct cytoplasmic connections in electrical synapses?

Proteins called connexons.

What is the flow of information in an electrical synapse?

Bidirectional.

How does the speed of conduction in electrical synapses compare to chemical synapses?

It is very fast.

In which brain region are electrical synapses found to facilitate rhythmic breathing?

The brainstem.

What is the function of electrical synapses in the hypothalamus?

They are found in hormone-secreting neurons.

Which types of synapses are the most common in the nervous system?

Chemical synapses.

How do chemical synapses transmit signals?

Via chemical messengers called neurotransmitters.

What is the directionality of information flow in chemical synapses?

Unidirectional.

What components in the presynaptic axon terminals contain neurotransmitters?

Synaptic vesicles.

What does the postsynaptic cell use to detect neurotransmitters?

Specialized ligand-gated receptors.

What is the name of the physical space between the presynaptic and postsynaptic cells?

Synaptic cleft.

What specific ion flows into the axon terminal when it is depolarized by an action potential?

$$Ca^{2+}$$

Which specific channels allow the inward flow of $Ca^{2+}$ at the axon terminal?

Voltage-gated $Ca^{2+}$ channels.

By what process are neurotransmitters released into the synaptic cleft?

Exocytosis.

Where must an action potential be induced in the postsynaptic cell for signal transmission to continue?

The axon hillock.

What protein acts as a $Ca^{2+}$ sensor in the synaptic vesicle membrane?

Synaptotagmin.

Which protein is also known as VAMP in the synaptic vesicle membrane?

Synaptobrevin.

Which two proteins on the plasma membrane form the SNARE complex with synaptobrevin?

SNAP-25 and Syntaxin.

What is the role of $Ca^{2+}$-bound synaptotagmin?

It catalyzes membrane fusion by binding to SNAREs and the plasma membrane.

In the synaptic vesicle cycle, what is the step immediately following docking?

Priming.

What protein is specifically associated with clathrin-mediated recycling of vesicles?

Clathrin.

What is the effect of Botulinum and Tetanus toxins on the synapse?

They affect SNARE proteins involved in vesicle fusion.

What is the specific action of Latrotoxin?

It triggers vesicle fusion.

What does Lambert-Eaton Myasthenic Syndrome (LEMS) attack?

Presynaptic $Ca^{2+}$ channels.

How do ionotropic receptors operate?

As ligand-gated ion channels.

What characterizes the transmission speed of metabotropic receptors?

Slow transmission.

Through what intermediaries do metabotropic receptors act to open ion channels?

Second messengers (G proteins).

What does EPSP stand for?

Excitatory postsynaptic potential.

What does IPSP stand for?

Inhibitory postsynaptic potential.

The influx of which ion is typically associated with an EPSP?

$$Na^+$$

The influx of which ion is typically associated with an IPSP?

$$Cl^-$$

What term describes the brief changes in membrane potential that determine if a neuron reaches threshold?

Postsynaptic potentials.

What process occurs at the axon hillock when a cell integrates excitation and inhibition?

Summation.

What happens if inhibition counteracts excitation in the postsynaptic neuron?

No action potential is triggered.

Which type of neurotransmitter receptor provides fast transmission?

Ionotropic receptors.

Besides the brainstem and hypothalamus, name two other locations where electrical synapses are found.

Cortex, thalamus, or cerebellum.

What is the function of neurotransmitter transporters in the vesicle membrane?

Neurotransmitter uptake.

What is the result of additional excitation overcoming inhibition in a neuron?

An action potential is triggered.