Self-Assessment 3.1

. The main function of dendritic spines is

to provide locations for synapse formation.

to retrieve neurotransmitter molecules after they've been released into the synapse.

to attract migrating neurons during fetal brain development.

to keep axon terminals of the presynaptic cell from getting too close to the dendrites of the postsynaptic cell.

. Which of the following is not a criterion for a chemical substance to qualify as a neurotransmitter?

The presynaptic cell should contain the proposed substance along with a mechanism for manufacturing it.

Receptors for the proposed substance should be present on the postsynaptic cell.

Direct application of the proposed substance or of an agonist drug that acts on its receptors should have the same effect on the postsynaptic cell as stimulating the presynaptic neuron.

A neuron that synthesizes the substance should also possess enzymes that break down that same substance.

. Lipid and gaseous transmitters

are stored in and released from synaptic vesicles.

were the first kinds of transmitters to be discovered in the brain.

often function as retrograde messengers.

usually remain in the vicinity of the synaptic cleft after being released.

. Which of the following statements about autoreceptors is true?

Autoreceptors are usually located on the membrane of synaptic vesicles.

When a transmitter molecule binds to an autoreceptor, the molecule is transported into the neuron.

The main function of autoreceptors is to inhibit neurotransmitter release, either directly at the nerve terminal or indirectly by slowing the cell's firing rate.

Autoreceptors for a particular transmitter are located on the dendrite of the postsynaptic cell.

. When a drug like cocaine blocks the reuptake of a neurotransmitter,

the transmitter molecules are prevented from diffusing away from the synapse.

synaptic transmission using that transmitter is enhanced.

synaptic vesicles are prevented from taking up the transmitter.

None of the above

. The gut-brain axis refers to

how neurons in the brain control feelings of hunger.

hormones synthesized in the brain that travel to the gut to control insulin secretion.

communication between the gut and the brain consisting of neural, immune, endocrine, and metabolic components.

how infectious bacteria or viruses that enter our gut influence the brain to make us feel sick.

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