Question 1

Synaptic malfunction or dysfunction may cause which of the following diseases?
A)myasthenia gravis
B)Parkinson's disease
C)schizophrenia
D)depression
E)All of these are correct.

Accepted Answer

Synaptic malfunction or dysfunction can lead to various diseases such as myasthenia gravis, Parkinson's disease, schizophrenia, and depression.

Question 2

______ trigger fusion of synaptic vesicles with the synaptic membranes of the presynaptic cell.This same stimulus also triggers ________.
A)Ca2+ ions,exocytosis
B)Ca2+ ions,endocytosis
C)acetylcholine,exocytosis
D)acetylcholine,endocytosis
E)Na+ ions,exocytosis

Accepted Answer

Ca2+ ions trigger fusion of synaptic vesicles with the synaptic membranes of the presynaptic cell in the process of exocytosis.

Question 3

How do Na+ ions enter a neuron when an action potential is initiated?
A)the Na+/K+-ATPase
B)a gated Na+ pump
C)a voltage-gated Na+ channel
D)the ligand-gated Na+ channel
E)a voltage-gated Na+ facilitated transporter

Accepted Answer

During the initiation of an action potential, voltage-gated Na+ channels open, allowing positive Na+ ions to flow into the neuron, depolarizing the cell and causing the action potential to propagate along the axon.

Question 4

What is caused by the inability of Na+ ion channels to open for several milliseconds after their inactivation?
A)hyperpolarization
B)depolarization
C)termination
D)a refractory period
E)an action potential

Accepted Answer

The inability of Na+ ion channels to open after their inactivation creates a refractory period, during which no new action potentials can be generated until the channels have recovered and are able to open again.

Question 5

Tetrahydrocannabinol,the active ingredient in marijuana,binds to receptors located in the ________ terminals of certain brain neurons.It lowers the likelihood that these neurons will release ________.
A)postsynaptic,neurotransmitters
B)presynaptic,neurotransmitters
C)presynaptic,Ca2+ ions
D)postsynaptic,Ca2+ ions
E)dendritic,neurotransmitters

Accepted Answer

Tetrahydrocannabinol binds to presynaptic receptors and lowers the likelihood that neurons will release neurotransmitters.

Question 6

The ability,possessed by all organisms,to respond to external stimulation is known as _______.
A)excitation
B)irritability
C)irritation
D)irrigation
E)irrigatability

Accepted Answer

Irritability is the ability of an organism to respond to external stimuli, such as light, heat, touch or chemicals. It allows organisms to change their behaviour or physiology in response to their surroundings. Excitation refers specifically to the process by which a neuron becomes activated and sends a signal. Irritation refers to a response of tissue to injury or infection. Irrigation is the process of supplying water to an area of land to help crops grow. Irrigatability is not a word.

Question 7

Which site in a neuron receives incoming information from external sources?
A)Dendrites
B)Axon
C)Axon hillock
D)Terminal knob
E)Cell body

Accepted Answer

Dendrites are the site in a neuron that receive incoming information from external sources, such as other neurons or sensory receptors. The information is then transmitted to the cell body and potentially passed along to the axon for further signaling.

Question 8

Impulse propagation by a myelinated axon is called ________ conduction.
A)saltatory
B)myelinated
C)rapid fire
D)jump stop
E)leap frog

Accepted Answer

Saltatory conduction refers to the rapid propagation of action potentials along myelinated axons, where the depolarization jumps from node to node. This allows for faster and more efficient conduction compared to unmyelinated axons.

Question 9

What is thought to cause the sodium channels that initiate an action potential to be inactivated for a brief time after being open for about 1 msec?
A)a higher positive charge
B)a higher negative charge
C)the random diffusion of an inactivation peptide into the opening of the channel pore
D)removal of a peptide from the channel protein
E)covalent addition of a peptide to the cytoplasmic end of the channel protein

Accepted Answer

The brief inactivation of sodium channels after being open for about 1 msec is known as the refractory period. It is thought to be caused by the diffusion of an inactivation peptide into the opening of the channel pore, which blocks ion flow. This mechanism ensures that action potentials travel in only one direction and also limits the rate at which they can be generated.

Question 10

Long-term potentiation is associated with NMDA receptors,one of several types of receptors that bind to the excitatory neurotransmitter _______.Its binding opens an internal cation channel within the receptor that allows _____ influx into the postsynaptic neuron,triggering a cascade of biochemical changes that lead to synaptic strengthening.
A)GABA,Ca2+ ion
B)glutamate,Ca2+ ion
C)glutamate,K+ ion
D)GABA,K+ ion
E)acetylcholine,Ca2+ ion

Accepted Answer

Long-term potentiation is associated with the binding of the excitatory neurotransmitter glutamate to NMDA receptors. This binding allows Ca2+ ion influx into the postsynaptic neuron, triggering a cascade of biochemical changes that lead to synaptic strengthening.

Question 11

As an action potential is initiated,the membrane is ______.This is caused by the ____ of ____ ions.
A)hyperpolarized,efflux,Na+
B)depolarized,influx,Na+
C)depolarized,influx,K+
D)hyperpolarized,influx,Na+
E)depolarized,efflux,Na+

Accepted Answer

As an action potential is initiated, the membrane is depolarized. This is caused by the influx of Na+ ions. Choice B correctly corresponds to these events.

Question 12

Where in a myelinated axon are nearly all of the ion channels concentrated?
A)the cell body
B)nodes of Ranvier
C)dendrites
D)axon terminals
E)neuron nucleus

Accepted Answer

Nearly all of the ion channels in a myelinated axon are concentrated at the nodes of Ranvier, which are the gaps or interruptions in the myelin sheath where the axonal membrane is exposed. This clustering of ion channels at the nodes of Ranvier facilitates the rapid and efficient propagation of action potentials along the axon.

Question 13

___________ is a process that strengthens certain synapses by repeated neuron stimulation over a short time period.
A)Denturation
B)Long term potentiation
C)Short term memory
D)Temporality
E)Long term deviation

Accepted Answer

This process is known as long term potentiation (LTP). It involves the repeated stimulation of certain synapses, which leads to the strengthening of the connections between the neurons involved. This can enhance the ability to remember and learn new information.

Question 14

What causes the membrane potential to return to the normal negative value after an action potential has occurred?
A)opening of a voltage-gated K+ channel
B)opening of a voltage-gated Na+ channel
C)closing of a voltage-gated K+ channel
D)opening of a ligand-gated Na+ channel
E)opening of a voltage-gated K+ facilitated transporter

Accepted Answer

The answer of What causes the membrane potential to return...

Question 15

Cocaine acts by _________.
A)enhancing the degradation of acetylcholine.
B)depressing the degradation of acetylcholine
C)interfering with dopamine reuptake from the synaptic cleft
D)enhancing dopamine reuptake from the synaptic cleft
E)destroying dopamine in the synapse

Accepted Answer

Cocaine interferes with dopamine reuptake from the synaptic cleft, leading to increased dopamine levels and the pleasurable feelings associated with cocaine use.

Question 16

How is a nerve impulse usually transmitted across a synapse from a presynaptic to a postsynaptic cell?
A)via a direct connection
B)via a spark
C)via a neurotransmitter
D)via Na+ ions
E)via plasmodesmata

Accepted Answer

A nerve impulse is transmitted across a synapse via a neurotransmitter, which is released from the presynaptic cell and binds to receptors on the postsynaptic cell. This leads to the opening of ion channels and the depolarization of the postsynaptic cell, allowing the impulse to continue along the axon. Choices A, B, D, and E are incorrect as they do not accurately describe the process of synaptic transmission.

Question 17

Which disease below is caused by the deterioration of the myelin sheath?
A)myasthenia gravis
B)multiple sclerosis
C)muscular dystrophy
D)diabetes mellitus
E)lupus erythematosus

Accepted Answer

Multiple sclerosis is caused by the deterioration of the myelin sheath, the protective covering that surrounds nerve fibers in the central nervous system. This leads to disruptions in the transmission of nerve impulses, resulting in a range of symptoms including muscle weakness, difficulty walking, and problems with vision and coordination.

Question 18

Which part of a neuron conducts impulses away from the cell body toward the target cell(s)?
A)axon hillock
B)cell body
C)dendrites
D)axon
E)terminal knob

Accepted Answer

The axon is the part of the neuron that conducts impulses away from the cell body toward the target cell(s). The axon hillock is the region where the axon emerges from the cell body, and the terminal knob is the endpoint of the axon where neurotransmitters are released to communicate with the target cell(s). The cell body contains the nucleus and other organelles, while dendrites receive signals from other neurons and conduct them toward the cell body.

Question 19

Where is the neuron cell nucleus located?
A)axon hillock
B)cell body
C)dendrites
D)axon
E)terminal knob

Accepted Answer

The nucleus of a neuron cell is located in the cell body, which is also known as the soma of the neuron. The axon hillock is the region where the axon originates from the cell body, dendrites receive input from other neurons, the axon is the main part of the neuron that carries information away from the cell body, and the terminal knob is the end of the axon where it forms a synapse with another neuron or target cell.

Question 20

What happens after a subthreshold depolarization?
A)a full action potential
B)a partial action potential
C)no action potential
D)a proportional action potential
E)a reversal of the direction of the neural impulse

Accepted Answer

A subthreshold depolarization means that the neuron did not reach the threshold necessary to trigger an action potential. Therefore, no action potential will be generated.

Quiz 4: The Structure and Function of the Plasma Membrane

Synaptic malfunction or dysfunction may cause which of the following diseases?

trigger fusion of synaptic vesicles with the synaptic membranes of the presynaptic cell.This same stimulus also triggers __.

How do Na+ ions enter a neuron when an action potential is initiated?

What is caused by the inability of Na+ ion channels to open for several milliseconds after their inactivation?

Tetrahydrocannabinol,the active ingredient in marijuana,binds to receptors located in the terminals of certain brain neurons.It lowers the likelihood that these neurons will release .

The ability,possessed by all organisms,to respond to external stimulation is known as _______.

Which site in a neuron receives incoming information from external sources?

Impulse propagation by a myelinated axon is called ________ conduction.

What is thought to cause the sodium channels that initiate an action potential to be inactivated for a brief time after being open for about 1 msec?

As an action potential is initiated,the membrane is __.This is caused by the of ions.

Where in a myelinated axon are nearly all of the ion channels concentrated?

___________ is a process that strengthens certain synapses by repeated neuron stimulation over a short time period.

What causes the membrane potential to return to the normal negative value after an action potential has occurred?

Cocaine acts by _________.

How is a nerve impulse usually transmitted across a synapse from a presynaptic to a postsynaptic cell?

Which disease below is caused by the deterioration of the myelin sheath?

Which part of a neuron conducts impulses away from the cell body toward the target cell(s) ?

Where is the neuron cell nucleus located?

What happens after a subthreshold depolarization?