MEGA EXAM LOAD

At the presynaptic terminal, the influx of which ion triggers neurotransmitter release?

Calcium (Ca²⁺)

What primarily contributes to the synaptic delay observed at chemical synapses?

The time needed for voltage‐gated Ca²⁺ channels to open, trigger vesicle fusion, and for neurotransmitters to diffuse across the synaptic cleft.

If a neuron’s sodium–potassium pump were inhibited, which of the following would most likely occur over time?

The ionic gradients would gradually diminish, impairing the ability to generate action potentials.

Postsynaptic receptors are critical for synaptic transmission because they:

Convert chemical signals (neurotransmitter binding) into electrical changes in the postsynaptic neuron.

Which of the following best describes the role of neurotransmitter receptors on the postsynaptic membrane?

They bind incoming transmitter molecules, altering the postsynaptic cell

Myelin sheaths around axons

are produced by oligodendrocytes (in CNS) and Schwann cells (in PNS)

The sodium–potassium pump directly generates the action potential.

False

Reuptake

Neurotransmitters are actively transported back into the presynaptic terminal for reuse.

Degradation

Neurotransmitters are enzymatically broken down into inactive molecules.

Diffusion

Neurotransmitters passively disperse out of the synaptic cleft into the surrounding space

Which type of synapse is described as an axon forming a connection directly onto a dendrite?

Axo‐dendritic synapse

Spatial summation in a neuron refers to:

The integration of multiple postsynaptic potentials arriving simultaneously at different locations on the cell

Which structure is part of the basal ganglia and is strongly associated with the control of movement?

Caudate nucleus

Which factor would most likely enhance the effectiveness of spatial summation at the axon hillock?

Synapses located closer to the axon hillock.

Which of the following is a major function of the hypothalamus?

Regulating hunger, thirst, and hormonal systems

Which of the following best describes a neurotransmitter antagonist?

A molecule that binds to the receptor without activating it, thereby blocking the action of the neurotransmitter.

During the initial (depolarizing) phase of an action potential, which ion’s influx is primarily responsible?

Sodium (Na⁺)

What is one likely consequence of damage specifically to the axon hillock region?

A reduced ability to integrate synaptic inputs, leading to impaired action potential initiation.

An inhibitory postsynaptic potential (IPSP) results in:

Hyperpolarization of the postsynaptic membrane, making it less likely to fire

Temporal summation is defined as:

The summing of postsynaptic potentials from the same synapse when they occur in rapid succession

Which directional term in neuroanatomy means “toward the belly” (and thus, underneath the brain when viewed upright)?

Ventral

Which of the following is true about the four lobes of the cerebral cortex?

The frontal lobe is critical for motor control and executive functions

The absolute refractory period limits the maximum frequency at which a neuron can fire an action potential.

True

Which statement correctly contrasts the propagation of action potentials with that of graded potentials?

Action potentials are actively propagated along the axon without decrement, whereas graded potentials passively spread and decay over distance.

Following an action potential, the membrane potential often becomes briefly more negative than the resting potential—a phenomenon known as afterhyperpolarization.

True

What is the typical resting membrane potential of a neuron?

-50 to -80 mV

Which of the following best describes neurophysiology?

The study of the electrical and chemical processes that underlie neural communication

Which of the following best summarizes the process of chemical synaptic transmission?

An action potential arrives at the presynaptic terminal, triggering Ca²⁺ influx that causes vesicle fusion and neurotransmitter release; the neurotransmitter then binds to postsynaptic receptors to generate a postsynaptic potential, and its effect is quickly terminated by degradation or reuptake.

What is the implication of the all‐or‐none property for neural information encoding?

Stimulus intensity is encoded by the frequency (rate) of action potentials rather than their amplitude.

Which of the following best distinguishes the absolute refractory period from the relative refractory period?

During the absolute refractory period, no stimulus (regardless of strength) can trigger an action potential; during the relative refractory period, only a stimulus stronger than normal can elicit one.

Inhibitory postsynaptic potentials (IPSPs) hyperpolarize the postsynaptic membrane and decrease the likelihood of an action potential.

True

How does the time interval between successive EPSPs affect the likelihood of triggering an action potential?

Shorter intervals result in overlapping EPSPs, increasing the chance of reaching threshold.

The limbic system includes the amygdala and hippocampus, which are strongly associated with

emotion and memory

The passive decay of graded potentials is primarily due to the resistance and capacitance properties of the neuronal membrane.

True

Which statement best describes the thalamus?

It relays sensory information to appropriate cortical regions

Voltage‐gated sodium channels open during the rising phase of an action potential and rapidly inactivate thereafter.

True

Which imaging method is most suitable for mapping brain structure with high spatial resolution without using ionizing radiation?

MRI

Which of the following best differentiates the roles of axons and dendrites?

Axons conduct all‐or‐none action potentials, whereas dendrites primarily receive inputs and conduct graded potentials.

Which cell type is responsible for forming myelin sheaths in the central nervous system?

Oligodendrocytes

Which layer of the meninges is the innermost and closely adheres to the surface of the brain?

Pia Mater

Which of the following best distinguishes graded (local) potentials from action potentials?

Graded potentials vary in amplitude and decay over distance, whereas action potentials are all‐or‐none and actively propagated without decrement.

Damage to the axon hillock would most likely impair a neuron’s ability to:

Integrate incoming synaptic inputs to decide whether to fire an action potential.

What is the primary function of the axon hillock?

Deciding whether to send an electrical signal down the axon

Which statement best describes the “all‐or‐none” property of action potentials?

An action potential is only generated if the membrane potential reaches a fixed threshold, and its amplitude does not vary with stimulus strength

What is one consequence of demyelination, as seen in conditions like multiple sclerosis?

Slowed conduction velocity along axons, leading to impaired neural communication.

The primary function of a postsynaptic receptor is to:

Bind neurotransmitter molecules and initiate a postsynaptic potential

Penfield's electrical stimulation mapping revealed that the somatosensory cortex is organized in a somatotopic manner. This means that:

Different body parts are represented in distinct, spatially ordered regions of the cortex.

Saltatory conduction refers to:

The “jumping” of the action potential from one node of Ranvier to the next on a myelinated axon

Which statement about TMS (transcranial magnetic stimulation) is correct?

TMS uses powerful magnets to briefly stimulate cortical areas directly

The sodium–potassium pump is responsible for:

Actively transporting Na⁺ out and K⁺ into the neuron to maintain ionic gradients

The decision for a postsynaptic neuron to fire an action potential is determined primarily by:

The summation of all excitatory and inhibitory postsynaptic potentials at the axon hillock.

The effect of a drug is based on its receptor binding affinity and its concentration. To be equally effective, a drug with low affinity will require a(n) ______ concentration compared to a drug with high affinity.

Higher

A decrease in physiological response after repeated drug exposure is called ______.

Tolerance

Which process involves the formation of connections between neurons as axons and dendrites extend?

Synaptogenesis

Which one of the following statements best demonstrates epigenetic effects on gene expression?

Mice raised by foster parents behave more like their foster parents than their genetic parents

Enzymatic degradation

Breakdown of neurotransmitters by enzymes.

Exocytosis

Neurotransmitter release into the synaptic cleft.

Reuptake

Reabsorption of neurotransmitters into the presynaptic neuron.

If one eye of a kitten is occluded during the sensitive period, visual cortex cells later show ______ responses to visual stimuli presented to that eye

Decreased

Children who have inherited phenylketonuria (PKU) can be helped by

Dietary manipulation

Methylation ______ gene expression through ______

Inhibits; DNA modification

The nervous system originates from which embryonic germ layer?

Ectoderm

The neurotransmitter ______ is found in nuclei of the basal forebrain.

Acetylcholine

Selective reuptake inhibitors (e.g., SSRIs) increase neurotransmitter concentration in the synaptic cleft by blocking reuptake.

True

Which chemical is not an amino acid neurotransmitter?

Dopamine

What structure forms when the neural groove closes during early embryonic development?

Neural Tube

Which feature does not normally change during the life span?

Genotype

Epigenetics

The study of heritable changes in gene expression that do not alter the DNA sequence.

Genotype

The complete set of genetic information inherited by an individual.

Methylation

A chemical modification of DNA that generally reduces gene expression.

Rodent pups with an inattentive mother secrete an abnormally high level of glucocorticoids in response to stress as adults. In terms of epigenetics, this response is due to

Methylation of the gene for the glucocorticoid receptor

A patient in the hospital requires anti-nausea medication. Which procedure provides the most rapid route of administration?

IV drip

Which of the following represents the correct sequence of cellular events during early brain development?

Neurogenesis, cell migration, cell differentiation, synaptogenesis, neuronal cell death, synapse rearrangement

In a dose-response curve, the ED50 is defined as:

The dose at which a drug produces 50% of its maximal effect.

Metabotropic receptors directly open ion channels when activated.

False

In neurogenesis, cells that give rise to neurons divide via mitosis in the ______ zone inside the neural tube

Ventricular

Which of the following is an example of epigenetics?

Mothering style affects the developing brain

The “sensitive period” in visual development refers to:

A developmental window when visual experience strongly and permanently shapes the visual cortex.

What is “reuptake” in synaptic transmission?

It is the reabsorption of neurotransmitters by the presynaptic neuron.

Phenylketonuria (PKU) is a hereditary disorder that involves faulty metabolism of

Protein

Teenagers with the highest IQ show

An especially long period of cortical thinning

In the developing neural tube, where does the mitosis of progenitor cells primarily occur?

In the ventricular zone

Which of the following factors have been shown to enhance adult hippocampal neurogenesis? (Select all that apply.)

Exercise, Environmental enrichment, Cognitive training

Which of the following would not be considered an extrinsic influence on cells?

Genes

Which neurotransmitter is known as the brain’s primary inhibitory chemical?

GABA

Down-regulation of a neuron’s receptors might be caused by ______.

The agonistic effects of a drug

The human brain continues to refine its synaptic connections—through processes like pruning—well into adolescence, which helps improve cognitive efficiency.

True

People who have used a particular dose of a drug several times may develop a similar response to the same dosage of other drugs in the same class. This is an example of ______.

Cross-tolerance

A higher drug dosage binds a higher proportion of receptors, thereby increasing the response. This relationship is called the ______.

Dose-response curve

What is the primary function of voltage-gated Ca²⁺ channels at the axon terminal?

They open to allow calcium influx that triggers vesicle fusion.

The mitotic division of nonneural cells to produce neurons is called

Neurogenesis

Which statement best explains the concept of drug tolerance?

Repeated exposure can lead to decreased receptor sensitivity or receptor number.

Benzodiazepines relieve anxiety by acting on which receptor?

GABAA receptor

Verapamil inhibits neurotransmitter release by blocking ______.

Calcium channels

Which chemical is not a monoamine neurotransmitter?

Acetylcholine

Projections using norepinephrine originate in which one of the following structures?

Locus coeruleus

Dopamine

Plays a key role in motor control and reward

Acetylcholine (ACh)

Functions in both the peripheral nervous system (neuromuscular junction) and brain.

Serotonin (5-HT)

Involved in mood regulation, sleep, and appetite.

Alzheimer’s disease is simply the inevitable result of normal aging and shows no distinct pathological changes in the brain.

False