Question 1

The effect of a particular neurotransmitter on postsynaptic neurons

Accepted Answer

The effect of a particular neurotransmitter on postsynaptic neurons depends on the properties of the postsynaptic neuron, such as the receptor subtypes present. Additionally, the effect may be modulated by the presence or absence of another neurotransmitter, such as an agonist or antagonist of a receptor subtype. Therefore, option D, which states that the effect depends on the properties of the postsynaptic neuron and may be modulated by the presence or absence of another neurotransmitter, is the best choice.

Question 2

Cerebrospinal fluid (CSF) is produced in the lateral and third ventricles by the

Accepted Answer

CSF is produced by the choroid plexus, a network of blood vessels located in the walls of the ventricles in the brain.

Question 3

Which of the following statements best describes the immediate consequence of neurotransmitter molecules binding to ligand-gated ion channel receptors?

Accepted Answer

When neurotransmitter molecules bind to ligand-gated ion channel receptors, the ion channel opens and allows the flow of ions through it, leading to changes in membrane potential and initiation of an action potential. This is known as synaptic transmission. The other options given describe other cellular processes that are not directly related to neurotransmitter binding to ligand-gated ion channels.

Question 4

The role of calcium ions (Ca²⁺) in synaptic transmission is to

Accepted Answer

Calcium ions play a key role in synaptic transmission by mediating the release of neurotransmitter molecules from the presynaptic neuron into the synaptic cleft, where they can bind to receptors on the postsynaptic membrane and transmit a signal. Once the action potential reaches the presynaptic terminal, voltage-gated calcium channels open, allowing calcium ions to flow into the terminal. The increased concentration of calcium triggers the exocytosis of synaptic vesicles containing neurotransmitter molecules, which diffuse across the synaptic cleft and bind to receptors on the postsynaptic membrane. Therefore, option B is the most appropriate choice.

Question 5

Compare the following analogy to chemical synaptic transmission: Two postage companies use different methods for delivery. Company One's method is to send a delivery person out with packages that will be delivered directly to the address on the label. Company Two's method is to send a delivery person out to a transfer center, and a second driver will deliver the package to the address. Company One's method best compares to ___________________, while Company Two's method best compares to ___________________. Company ___ uses a faster method.

Accepted Answer

Ligand-gated ion channels directly open in response to neurotransmitter binding, similar to direct delivery. GPCRs involve a secondary messenger system, akin to a transfer center. Company One's method is faster, like ligand-gated ion channels.

Question 6

Gray matter is to white matter as ________ are to ________.

Accepted Answer

Gray matter primarily consists of cell bodies, while white matter is primarily composed of axon tracts. Therefore, the analogy would be between cell bodies and axon tracts, making choice C the best option.

Question 7

The two main divisions of the central nervous system are the

Accepted Answer

The central nervous system is composed of the brain and the spinal cord. These are the two main anatomical components of the system. While the forebrain and brainstem are important divisions within the brain, and the cerebral hemispheres and cerebellum are specific parts of the brain, neither of these options accurately captures the two main divisions of the entire central nervous system. Similarly, while white matter and gray matter are types of tissue found in the brain and spinal cord, they do not represent two separate divisions of the system.

Question 8

A gap junction is

Accepted Answer

A gap junction is a type of intercellular junction that allows direct communication between the cytoplasm of two adjacent cells. It is formed by transmembrane channels composed of connexins that span the plasma membranes of the two cells and create a pore that permits the passage of ions, molecules, and electrical signals. Gap junctions are found at electrical synapses and are important for synchronizing the activity of groups of neurons or muscle cells.

Question 9

Which of the following sequences of steps best represents the order of events that occur during synaptic transmission?

Accepted Answer

The release of neurotransmitter from the presynaptic cell occurs first, followed by diffusion across the synapse, and finally binding of neurotransmitter at the postsynaptic membrane. This sequence of events is necessary for neuronal signaling to occur, as the release of neurotransmitter is what triggers communication between the pre- and postsynaptic cells.

Question 10

The specialized structures that comprise the midbrain control functions such as

Accepted Answer

The midbrain is responsible for controlling various functions related to vision, including visual reflexes such as the pupillary reflex and the oculomotor reflex. These reflexes help in the rapid adjustments of visual attention and maintenance of visual stability during movement. While the midbrain does play a role in other functions such as emotional processing and memory, these are primarily controlled by other areas of the brain. Hormone regulation is mainly controlled by the hypothalamus, which is also a part of the midbrain, but not its primary function.

Question 11

Many drugs produce their effects by facilitating or interfering with neurotransmitters at synapses. Which of the following drugs would most likely increase the effect of serotonin?

Accepted Answer

If a drug prevents the breakdown of serotonin molecules in the synaptic cleft, then the concentration of serotonin in the synaptic cleft will increase, leading to increased activation of serotonin receptors and increased serotonin effects. Therefore, option B is the correct answer. Option A describes a drug that binds to serotonin receptors without affecting membrane permeability to ions and may or may not increase serotonin effects. Option C describes a drug blocking the effect of Ca2+ and IP3 ions, which are not directly related to serotonin effects. Option D describes a drug blocking the effect of a conditional neurotransmitter, which may or may not affect serotonin effects depending on the specific neurotransmitter and pathway involved.

Question 12

Which of the following cells produce myelin in the peripheral nervous system?

Accepted Answer

Schwann cells are the glial cells that produce myelin in the peripheral nervous system. Astrocytes and microglia are found in the central nervous system and oligodendrocytes produce myelin in the central nervous system, not the peripheral nervous system.

Question 13

The ___________, which is comprised of _________, restricts the diffusion of certain molecules and microbes from the circulatory system, protecting the brain from chemical compounds that might otherwise interfere with neuronal activity.

Accepted Answer

The blood-brain barrier, which is composed of astrocytes, restricts certain molecules and microbes from the circulatory system, protecting the brain from chemical compounds that might interfere with neuronal activity. The other options listed do not specifically refer to the blood-brain barrier.

Question 14

The difference between gray matter and white matter is that gray matter refers to ________, whereas white matter refers to ________.

Accepted Answer

Gray matter refers to the areas of the brain that contain cell bodies, while white matter refers to the areas that contain axon tracts.

Question 15

Which of the following cells devour and remove damaged brain cells?

Accepted Answer

Microglia are the immune cells of the central nervous system and are responsible for removing damaged or dying brain cells. Astrocytes are supportive cells, Oligodendrocytes produce myelin, and Schwann cells produce myelin in the peripheral nervous system.

Question 16

Which of the following is NOT a mechanism for removing a neurotransmitter from the synaptic cleft?

Accepted Answer

Transport of the neurotransmitter by ion channels into neighboring glial cells is not a mechanism for removing a neurotransmitter from the synaptic cleft. The other three options, diffusion, active reuptake, and enzymatic breakdown, are all mechanisms for removing a neurotransmitter from the synaptic cleft.

Question 17

Consider the synapse shown schematically here.  If neuron A causes neuron B to become hyperpolarized relative to B's resting state,

Accepted Answer

When neuron A causes neuron B to become hyperpolarized, neuron B's membrane potential becomes more negative than its resting state, making it less likely to reach its threshold for firing an action potential. As a result, neuron B is also less likely to release neurotransmitter molecules from its axon terminal, which are necessary for transmitting signals to other neurons or target cells. In hyperpolarization, there is no significant activation of voltage-gated channels for potassium or sodium, so options C and D are not correct.

Question 18

The brainstem includes all of the following components EXCEPT the

Accepted Answer

The hypothalamus is not considered part of the brainstem. The brainstem consists of the medulla, midbrain, and pons. The hypothalamus is located in the forebrain, below the thalamus.

Question 19

The thick outer membrane that encloses the brain within the skull is the

Accepted Answer

The thick outer membrane that encloses the brain within the skull is called the dura mater. Gray matter and white matter refer to the different types of tissue within the brain, while the myelin sheath is a fatty covering that surrounds and insulates some nerve fibers.

Question 20

Which of the following is a catecholamine?

Accepted Answer

Catecholamines are a group of neurotransmitters that include dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline). Out of the given options, only norepinephrine is a catecholamine.

Quiz 2: Structure and Function of the Nervous System