Basic Structure And Function Of The Nervous System! Trivia Quiz
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Which of the following is/are functions of the human nervous system?
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A. receiving, storing, and processing information on the internal and external environments
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B. bringing about changes in physiology and/or behavior to ensure optimal functions of homeostatic mechanisms
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C. secretion of hormones
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D. coordination of movement
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E. All of the choices are correct.
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The trivia quiz is on the basic structure and function of the nervous system! The nervous system is tasked with communication between the brain and all the organs in the body. Do you know the different nerves in the boy, and what task they accomplish? Do take up the quiz and get to find out for sure. All the best!
Quiz Preview
- 2.
The central nervous system includes the:
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A. afferent nerves and spinal cord.
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B. efferent nerves and spinal cord.
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C. autonomic nervous system and the brain.
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D. brain stem and the autonomic nervous system.
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E. brain and spinal cord.
Correct Answer
A. E. brain and spinal cord.Explanation
The central nervous system consists of the brain and spinal cord. These two structures are responsible for receiving and processing information from the body, as well as sending out signals to control bodily functions. The brain is the control center of the body, while the spinal cord acts as a pathway for transmitting signals between the brain and the rest of the body. Therefore, option E is the correct answer.Rate this question:
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- 3.
The Na+ and K+ channels that open during an action potential are voltage regulated, both opening in response to depolarization of the membrane.
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True
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False
Correct Answer
A. TrueExplanation
The explanation for the given correct answer is that during an action potential, the membrane depolarizes, meaning the inside of the cell becomes more positive. This change in voltage triggers the opening of the Na+ and K+ channels. The Na+ channels open first, allowing an influx of sodium ions into the cell, which further depolarizes the membrane. As the membrane potential reaches its peak, the K+ channels open, allowing an efflux of potassium ions out of the cell, which repolarizes the membrane. Therefore, both the Na+ and K+ channels open in response to depolarization of the membrane, making the statement true.Rate this question:
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- 4.
The efferent division of the peripheral nervous system consists of the somatic nervous system and the autonomic nervous system.
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True
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False
Correct Answer
A. TrueExplanation
The efferent division of the peripheral nervous system is responsible for transmitting signals from the central nervous system to the muscles and glands. It consists of two main components: the somatic nervous system, which controls voluntary movements, and the autonomic nervous system, which regulates involuntary functions such as heart rate and digestion. Therefore, the statement that the efferent division of the peripheral nervous system consists of the somatic nervous system and the autonomic nervous system is true.Rate this question:
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- 5.
Which is not true of myelin?
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A. It is a fatty membranous sheath.
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B. It is formed by glial cells.
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C. It influences the velocity of conduction of an electrical signal down an axon.
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D. It covers all parts of the neuron, including the axon, cell body, and dendrites.
Correct Answer
A. D. It covers all parts of the neuron, including the axon, cell body, and dendrites.Explanation
Myelin is a fatty membranous sheath that is formed by glial cells. It influences the velocity of conduction of an electrical signal down an axon. However, it does not cover all parts of the neuron, including the axon, cell body, and dendrites. Myelin primarily covers the axon, forming a protective layer that allows for faster transmission of electrical signals. The cell body and dendrites of a neuron are not covered by myelin.Rate this question:
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- 6.
The difference in electrical charge between two points:
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A. is called the potential difference between those points.
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B. is called the diffusion potential between those points.
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C. is called the the current, and is expressed in the units of millimoles.
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D. is the same for all ions.
Correct Answer
A. A. is called the potential difference between those points.Explanation
The difference in electrical charge between two points is referred to as the potential difference between those points. This potential difference is a measure of the electrical potential energy per unit charge, and it is commonly measured in volts. It represents the work done per unit charge in moving a positive test charge from one point to another in an electric field. The potential difference is an important concept in understanding electrical circuits and the flow of electric current.Rate this question:
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- 7.
According to the equation expressed as Ohm's law, which of these would cause the greatest increase in current?
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A. doubling both voltage and resistance
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B. reducing both voltage and resistance by half
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C. doubling voltage and reducing resistance by half
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D. reducing voltage by half and doubling resistance
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E. quadrupling both voltage and resistance
Correct Answer
A. C. doubling voltage and reducing resistance by halfExplanation
According to Ohm's law, the current (I) is directly proportional to the voltage (V) and inversely proportional to the resistance (R). Therefore, doubling the voltage will double the current, and reducing the resistance by half will also double the current. Hence, doubling the voltage and reducing the resistance by half will cause the greatest increase in current.Rate this question:
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- 8.
Which of these would occur if the concentration of ATP were depleted in a typical nerve cell?
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A. Resting membrane potential would become more negative.
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B. Resting membrane potential would become less negative.
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C. The concentration gradient for Na+ would remain the same.
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D. The resting membrane potential would eventually become positive inside with respect to outside.
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E. There would be no change in the resting membrane potential.
Correct Answer
A. B. Resting membrane potential would become less negative.Explanation
If the concentration of ATP were depleted in a typical nerve cell, the correct answer is B. Resting membrane potential would become less negative. ATP is required for active transport mechanisms, such as the sodium-potassium pump, which maintains the resting membrane potential by pumping sodium out of the cell and potassium into the cell. Without ATP, the sodium-potassium pump would not be able to function properly, leading to a decrease in the concentration gradient of ions and a less negative resting membrane potential.Rate this question:
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- 9.
During the rising (depolarizing) phase of a neuronal action potential
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A. PK+ becomes much greater than PNa+.
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B. PNa+ becomes much greater than PK+.
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C. PK+ is the same as PNa+.
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D. Na+ efflux (flow out of the cell) occurs.
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E. K+ flows rapidly into the cell.
Correct Answer
A. B. PNa+ becomes much greater than PK+.Explanation
During the rising (depolarizing) phase of a neuronal action potential, the correct answer is B. PNa+ becomes much greater than PK+. This is because during this phase, there is a rapid influx of sodium ions (Na+) into the cell through voltage-gated sodium channels. This influx of sodium ions causes the membrane potential to become more positive, leading to depolarization. At the same time, the efflux of potassium ions (K+) is relatively slower compared to the influx of sodium ions, resulting in a greater permeability of sodium ions compared to potassium ions.Rate this question:
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- 10.
The region of the brain that is the most important control area for homeostatic regulation of the internal environment is:
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A. the thalamus.
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B. the hippocampus.
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C. the cerebrum.
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D. the cerebellum.
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E. the hypothalamus.
Correct Answer
A. E. the hypothalamus.Explanation
The hypothalamus is the most important control area for homeostatic regulation of the internal environment. It plays a crucial role in regulating body temperature, hunger and thirst, sleep-wake cycles, and hormone production. It receives signals from various parts of the body and coordinates the appropriate response to maintain a stable internal environment. The thalamus, hippocampus, cerebrum, and cerebellum have different functions and are not primarily responsible for homeostatic regulation.Rate this question:
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- 11.
The portion of the peripheral nervous system that is composed of nerve fibers that innervate skeletal muscle is called the:
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A. afferent nervous system.
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B. sympathetic nervous system.
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C. parasympathetic nervous system.
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D. somatic motor nervous system.
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E. autonomic nervous system.
Correct Answer
A. D. somatic motor nervous system.Explanation
The correct answer is D. somatic motor nervous system. This is because the somatic motor nervous system is responsible for controlling voluntary movements of skeletal muscles. It consists of nerve fibers that transmit signals from the central nervous system to the skeletal muscles, allowing us to consciously control our movements. The other options (afferent nervous system, sympathetic nervous system, parasympathetic nervous system, autonomic nervous system) are all part of the autonomic nervous system, which controls involuntary functions of the body.Rate this question:
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- 12.
The cerebrum consists only of gray matter.
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True
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False
Correct Answer
A. FalseExplanation
The cerebrum does not consist only of gray matter. It is the largest part of the brain and is responsible for higher functions such as thinking, memory, and voluntary movements. It is composed of both gray matter, which contains the cell bodies of neurons, and white matter, which consists of myelinated axons that connect different parts of the brain. Therefore, the statement that the cerebrum consists only of gray matter is incorrect.Rate this question:
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- 13.
The lipid portion of a cell's plasma membrane constitutes a barrier to current.
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True
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False
Correct Answer
A. TrueExplanation
The lipid portion of a cell's plasma membrane is composed of a double layer of phospholipids, which creates a barrier that restricts the flow of charged particles, such as ions, and electric current across the membrane. This lipid barrier is essential for maintaining the integrity and selective permeability of the cell membrane, allowing it to regulate the movement of molecules and ions in and out of the cell. Therefore, the statement is true.Rate this question:
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- 14.
Catecholamines are the most abundant neurotransmitters in the CNS.
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True
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False
Correct Answer
A. FalseExplanation
Catecholamines are a class of neurotransmitters that include dopamine, norepinephrine, and epinephrine. While catecholamines are indeed present in the central nervous system (CNS), they are not the most abundant neurotransmitters. Other neurotransmitters such as glutamate and gamma-aminobutyric acid (GABA) are more abundant in the CNS. Therefore, the statement "Catecholamines are the most abundant neurotransmitters in the CNS" is false.Rate this question:
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- 15.
Opioid drugs, such as morphine, are agonists of a class of neurotransmitters called endorphins.
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True
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False
Correct Answer
A. TrueExplanation
Opioid drugs, including morphine, act as agonists for endorphins, which are a class of neurotransmitters. This means that they bind to the same receptors in the brain as endorphins and produce similar effects. Therefore, the statement is true.Rate this question:
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- 16.
Although nerve cells in each cerebral hemisphere make connections with other cells in the same hemisphere, there is no crossover of information between the two hemispheres.
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True
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False
Correct Answer
A. FalseExplanation
The statement is false because there is actually a crossover of information between the two hemispheres of the brain. This crossover occurs through a bundle of nerve fibers called the corpus callosum, which connects the left and right hemispheres and allows them to communicate and share information. This communication is essential for various brain functions, including language processing, perception, and coordination between the two sides of the body.Rate this question:
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- 17.
Which is TRUE about typical, resting neurons?
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A. The plasma membrane is most permeable to sodium ions.
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B. The concentration of sodium ion is greater inside the cell than outside.
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C. The permeability of the plasma membrane to potassium ions is much greater than its permeability to sodium ions.
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D. The plasma membrane is completely impermeable to sodium ions.
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E. The plasma membrane is completely impermeable to potassium ions.
Correct Answer
A. C. The permeability of the plasma membrane to potassium ions is much greater than its permeability to sodium ions.Explanation
The correct answer is C because resting neurons have a higher permeability to potassium ions compared to sodium ions. This is due to the presence of leak channels in the plasma membrane that allow potassium ions to pass through more easily. The concentration of sodium ions is actually higher outside the cell, creating an electrochemical gradient that drives sodium ions into the cell when channels are open. The plasma membrane is not completely impermeable to sodium ions, as they can still enter the cell through other channels such as voltage-gated channels. Similarly, the plasma membrane is not completely impermeable to potassium ions, as they can also exit the cell through other channels.Rate this question:
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- 18.
A threshold stimulus applied to an excitable membrane is one that is just sufficient to:
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A. trigger an excitatory postsynaptic potential.
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B. cause a change in membrane potential.
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C. trigger an action potential.
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D. be conducted to the axon hillock.
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E. depolarize a dendrite.
Correct Answer
A. C. trigger an action potential.Explanation
A threshold stimulus is the minimum level of stimulation required to generate an action potential in an excitable membrane. When this threshold is reached, the excitable membrane undergoes a rapid change in membrane potential, resulting in the generation of an action potential. This action potential is a brief electrical impulse that travels along the membrane, allowing for the transmission of signals between neurons. Therefore, the correct answer is C. trigger an action potential.Rate this question:
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- 19.
A graded potential in a membrane results in an electric current along an adjacent area of membrane and this current diminishes with distance from the site of the initial potential change.
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True
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False
Correct Answer
A. TrueExplanation
When a graded potential occurs in a membrane, it causes a change in the electrical charge along the membrane. This change in charge creates an electric current that spreads along the adjacent area of the membrane. However, as the current moves away from the initial site of the potential change, it gradually diminishes in strength. Therefore, the statement that a graded potential in a membrane results in an electric current along an adjacent area of membrane, and this current diminishes with distance from the site of the initial potential change, is true.Rate this question:
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- 20.
Because so many Na ions move into a cell during an action potential and so many K ions move out, no further action potentials can be generated in a given membrane until the Na, K-ATPase pumps can restore the concentration gradient.
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True
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False
Correct Answer
A. FalseExplanation
The statement is false because the restoration of the concentration gradient by Na, K-ATPase pumps is not necessary for generating further action potentials. The concentration gradient is restored by these pumps after an action potential, but it does not prevent the generation of new action potentials. The generation of action potentials depends on the opening and closing of ion channels, specifically voltage-gated channels, which are responsible for the depolarization and repolarization of the membrane.Rate this question:
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- 21.
Most of the parasympathetic ganglia lie in chains along the spinal cord called sympathetic trunks.
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True
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False
Correct Answer
A. FalseExplanation
The statement is false because parasympathetic ganglia do not lie in chains along the spinal cord called sympathetic trunks. Parasympathetic ganglia are located near or within the organs they innervate, while sympathetic ganglia are the ones that lie in chains along the spinal cord.Rate this question:
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- 22.
Which of the following is not true of glial cells?
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A. They form the myelin for axons.
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B. Neurons outnumber glial cells 10 to 1 in the nervous system.
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C. They deliver fuel molecules to neurons and remove the waste products of metabolism.
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D. They are important for the growth and development of the nervous system.
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E. They regulate the composition of the extracellular fluid in the CNS.
Correct Answer
A. B. Neurons outnumber glial cells 10 to 1 in the nervous system.Explanation
Glial cells are non-neuronal cells that support and protect neurons. Option B is not true because glial cells actually outnumber neurons in the nervous system. There are about 10 times more glial cells than neurons. Therefore, option B is the correct answer as it contradicts the actual ratio of neurons to glial cells in the nervous system.Rate this question:
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- 23.
Which is TRUE about the resting membrane potential?
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A. It requires very few ions to be distributed unevenly.
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B. It has the same value in all cells.
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C. It is oriented so that the cell's interior is positive with respect to the extracellular fluid.
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D. Only nerve and muscle cells have a potential difference across the membrane at rest.
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E. It is not altered by changing concentration gradients of permeating ions.
Correct Answer
A. A. It requires very few ions to be distributed unevenly.Explanation
The resting membrane potential is the electrical potential difference across the plasma membrane of a cell when it is at rest. It is maintained by the uneven distribution of ions across the membrane. Option A is true because the resting membrane potential is established by the unequal distribution of a few key ions, such as potassium (K+) and sodium (Na+), across the membrane. These ions are actively pumped in and out of the cell by ion channels, creating a charge imbalance and resulting in a negative internal charge compared to the external environment.Rate this question:
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- 24.
The diffusion potential due to the concentration gradient for Na+ across a nerve cell membrane:
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A. favors its movement into the cell at the resting membrane potential.
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B. favors its movement out of the cell at the resting membrane potential.
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C. is equal and opposite to the electrical potential acting on Na+ at the resting membrane potential.
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D. Is in the same direction as the diffusion potential due to the concentration gradient for K+.
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E. favors movement of Na+ in the opposite direction as the electrical potential acting on Na+ at the resting membrane potential.
Correct Answer
A. A. favors its movement into the cell at the resting membrane potential.Explanation
The correct answer is A because the concentration gradient for Na+ is higher outside the cell compared to inside the cell. This means that there is a higher concentration of Na+ outside the cell, creating a diffusion potential that favors the movement of Na+ into the cell. At the resting membrane potential, the electrical potential acting on Na+ is not strong enough to overcome the concentration gradient, so Na+ tends to move into the cell.Rate this question:
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- 25.
Which of the following is not known to be an important neurotransmitter in the CNS?
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A. Dopamine
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B. Acetylcholine
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C. Morphine
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D. Glutamate
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E. Substance P
Correct Answer
A. C. MorphineExplanation
Morphine is not known to be an important neurotransmitter in the CNS. While dopamine, acetylcholine, glutamate, and substance P are all well-established neurotransmitters in the central nervous system, morphine is not classified as a neurotransmitter. Morphine is an opioid analgesic that acts on opioid receptors in the brain to relieve pain, but it is not involved in the normal transmission of signals between neurons in the CNS.Rate this question:
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- 26.
Serotonin:
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A. acts as a neuromodulator.
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B. is a catecholamine neurotransmitter.
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C. is a neuropeptide.
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D. has an inhibitory effect on pathways that are involved in the control of muscles.
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E. has an excitatory effect on pathways that mediate sensations.
Correct Answer
A. A. acts as a neuromodulator.Explanation
Serotonin acts as a neuromodulator, which means it modulates or modifies the activity of other neurotransmitters in the brain. It does not directly transmit signals between neurons like a neurotransmitter, but instead influences the release, synthesis, and reuptake of other neurotransmitters. Serotonin plays a role in regulating mood, sleep, appetite, and other important physiological functions.Rate this question:
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- 27.
Which is FALSE about the equilibrium potential of a given ion across a membrane?
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A. It is a function of the concentration of that ion on both sides of the membrane.
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B. It is the potential at which there is no net movement of that ion across the membrane.
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C. It is the potential difference across the membrane at which an electric force favoring movement of the ion in one direction is equal in magnitude and opposite in direction to the diffusion force provided by the concentration difference of the ion across the membrane.
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D. A permeable ion will move in the direction that will tend to bring the membrane potential toward that ion's equilibrium potential.
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E. An anion that is in higher concentration inside the cell than outside the cell will have a negative eqilibrium potential.
Correct Answer
A. E. An anion that is in higher concentration inside the cell than outside the cell will have a negative eqilibrium potential.Explanation
The equilibrium potential of an ion is determined by the concentration gradient of that ion across the membrane. If an anion is in higher concentration inside the cell than outside, it means that there is a higher concentration of negatively charged ions inside the cell. Since the equilibrium potential is the potential at which there is no net movement of the ion across the membrane, the negative charge inside the cell will create a negative equilibrium potential to balance the diffusion force provided by the concentration difference. Therefore, the statement is true.Rate this question:
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- 28.
The equilibrium potential of K+ ions in nerve cells is about -90 mV. The membrane potential of typical nerve cells at rest is -70 mV. Therefore
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A. Increasing the permeability of a resting neuronal membrane to K+ will make the membrane potential more negative inside with respect to outside.
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B. In resting neurons, there is a net diffusion of K+ into the cell.
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C. changing the resting membrane potential of a neuron to -80 mV would increase K+ diffusion rate out of the cell.
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D. potassium is the only permanent ion at rest.
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E. there must be another permanent ion with an equilibrium potential more negative than -90 mV.
Correct Answer
A. A. Increasing the permeability of a resting neuronal membrane to K+ will make the membrane potential more negative inside with respect to outside.Explanation
Increasing the permeability of a resting neuronal membrane to K+ ions means that more K+ ions will be able to move across the membrane. Since the equilibrium potential of K+ ions is -90 mV, this means that the K+ ions will move out of the cell, making the inside of the membrane more negative with respect to the outside. Therefore, the correct answer is A.Rate this question:
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- 29.
Which is true about neuronal membrane electrical and concentration gradients at the peak of the action potential?
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A. The electrical gradient is in a direction that would tend to move K+ out of the cell.
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B. The concentration gradient for K+ is in a direction that would tend to move it into the cell.
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C. The concentration gradient for K+ greatly increases compared to at rest.
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D. The concentration gradient for Na+ is in a direction that would tend to move it out of the cell.
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E. The electrical gradient for Na+ is in a direction that would tend to move it into the cell.
Correct Answer
A. A. The electrical gradient is in a direction that would tend to move K+ out of the cell.Explanation
At the peak of the action potential, the neuronal membrane is depolarized, meaning that the inside of the cell becomes positively charged compared to the outside. This creates an electrical gradient that would tend to move positively charged ions, such as K+, out of the cell. Therefore, option A is correct.Rate this question:
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- 30.
Which of the following is not true about axon transport?
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A. It refers to the passage of materials from the cell body of a neuron to the axon terminals.
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B. It refers to the passage of materials from axon terminals to the cell body of a neuron.
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C. It refers to the transport of materials from the inside to the outside across the axonal membrane.
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D. It is especially important for maintaining the integrity of neurons with long axons.
Correct Answer
A. C. It refers to the transport of materials from the inside to the outside across the axonal membrane.Explanation
Axon transport refers to the passage of materials from the cell body of a neuron to the axon terminals. This process is crucial for maintaining the integrity of neurons with long axons. However, it does not involve the transport of materials from the inside to the outside across the axonal membrane.Rate this question:
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- 31.
Which is TRUE about the Na+, K+ ATPase pump in neurons?
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A. It generates a small electrical potential such that the inside is made negative with respect to the outside.
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B. It maintains a concentration gradient for K+ such that diffusion forces favor movement of K+ into the cell.
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C. It maintains an electrical gradient at the equilibrium potential of K+.
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D. It transports equal numbers of sodium and potassium ions with each pump cycle.
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E. It pumps 3 Na+ ions into the cell for every 2 K+ ions it pumps out.
Correct Answer
A. A. It generates a small electrical potential such that the inside is made negative with respect to the outside.Explanation
The Na+, K+ ATPase pump in neurons generates a small electrical potential that makes the inside of the cell negative compared to the outside. This is known as the resting membrane potential and is essential for the proper functioning of neurons. This electrical potential is created by the pump actively transporting 3 sodium ions out of the cell for every 2 potassium ions it pumps into the cell. This creates an imbalance of positive and negative charges across the cell membrane, resulting in a negative interior. Therefore, option A is the correct answer.Rate this question:
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- 32.
Which must happen in order for an action potential to begin?
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A. The membrane potential must be at the Na+ equilibrium potential.
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B. Na+ influx must exceed K+ efflux.
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C. The membrane must be out of the relative refractory period.
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D. Na+ channels must all be inactivated.
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E. Multiple inhibitory postsynaptic potentials (IPSPs) must summate.
Correct Answer
A. B. Na+ influx must exceed K+ efflux.Explanation
For an action potential to begin, the influx of sodium ions (Na+) into the cell must exceed the efflux of potassium ions (K+). This is because the opening of voltage-gated Na+ channels causes depolarization of the cell membrane, leading to the initiation of an action potential. The influx of Na+ ions causes the membrane potential to become more positive, while the efflux of K+ ions helps to repolarize the membrane after the action potential is generated. Therefore, option B is the correct answer.Rate this question:
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- 33.
Which describes the response of the voltage-gated channels when an axon is stimulated to threshold?
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A. K+ channels open before the Na+ channels.
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B. Na+ channels are activated and then inactivated.
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C. K+ channels open at the same time as the Na+ channels.
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D. K+ channels are opened when Na+ binds to the channel.
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E. K+ influx causes Na+ channels to inactivate.
Correct Answer
A. B. Na+ channels are activated and then inactivated.Explanation
When an axon is stimulated to threshold, the correct answer B states that Na+ channels are activated and then inactivated. This is because when the axon reaches threshold, the voltage-gated Na+ channels open, allowing Na+ ions to rush into the axon, which causes depolarization and the generation of an action potential. However, shortly after opening, these Na+ channels become inactivated, preventing further influx of Na+ ions. This inactivation is important for the proper propagation of the action potential along the axon.Rate this question:
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- 34.
Which of the following statements regarding neurotransmitters is TRUE?
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A. Acetylcholine is broken down by enzymes present on postsynaptic cell membranes.
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B. Acetylcholine that is released at synapses binds to adrenergic receptors in the postsynaptic cell membrane.
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C. Catecholamines are the most abundant neurotransmitters in the central nervous system.
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D. Opiate drugs, such as morphine, are antagonists of a class of neurotransmitters called endorphins.
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E. Gamma-aminobutyric acid (GABA) is a major excitatory transmitter in the central nervous system.
Correct Answer
A. A. Acetylcholine is broken down by enzymes present on postsynaptic cell membranes.Explanation
Acetylcholine is broken down by enzymes present on postsynaptic cell membranes. This is true because acetylcholine is broken down by the enzyme acetylcholinesterase, which is located on the postsynaptic cell membrane. This breakdown of acetylcholine helps to terminate its action and prevent continuous stimulation of the postsynaptic cell.Rate this question:
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- 35.
Ions other than Na+, K+, and Cl- play no role in generating the resting membrane potential of a cell.
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True
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False
Correct Answer
A. FalseExplanation
Ions other than Na+, K+, and Cl- play a role in generating the resting membrane potential of a cell. This is because the resting membrane potential is established by the concentration gradients of these ions across the cell membrane. Na+ and Cl- ions are more concentrated outside the cell, while K+ ions are more concentrated inside the cell. The movement of these ions across the membrane through ion channels contributes to the electrical charge difference across the cell membrane, which is the resting membrane potential. Therefore, ions other than Na+, K+, and Cl- do play a role in generating the resting membrane potential.Rate this question:
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- 36.
Spinal nerves are composed of the axons of both afferent and efferent neurons.
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True
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False
Correct Answer
A. TrueExplanation
Spinal nerves are indeed composed of the axons of both afferent and efferent neurons. Afferent neurons carry sensory information from the body to the central nervous system, while efferent neurons transmit motor signals from the central nervous system to the muscles and glands. The combination of these two types of neurons in spinal nerves allows for the bidirectional communication between the body and the central nervous system, enabling sensory perception and motor control.Rate this question:
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- 37.
The thalamus is the single most important control area for regulating the homeostasis of the internal environment.
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True
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False
Correct Answer
A. FalseExplanation
The thalamus is not the single most important control area for regulating the homeostasis of the internal environment. While the thalamus does play a crucial role in relaying sensory information to the cerebral cortex, it is not primarily responsible for regulating homeostasis. Other regions of the brain, such as the hypothalamus, are more involved in maintaining the body's internal balance and coordinating various physiological processes. Therefore, the statement is false.Rate this question:
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- 38.
Which of the following statements about the refractory period of a membrane is true?
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A. The absolute refractory period refers to the period of time during which another action potential cannot be initiated in that part of the membrane that is undergoing an action potential, no matter how great the strength of the stimulus.
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B. The relative refractory period refers to the period of time during which another action potential can be initiated in that part of the membrane that has just undergone an action potential if a stronger than normal stimulus is applied.
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C. The refractory period prevents the action potential from spreading back over the part of the membrane that just underwent an action potential.
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D. The refractory period places an upper limit on the frequency with which a nerve cell can conduct action potentials.
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E. All of the above choices are correct.
Correct Answer
A. E. All of the above choices are correct.Explanation
The correct answer is E. All of the above choices are correct.
The refractory period of a membrane refers to the period of time during which the membrane is unable to generate another action potential. The absolute refractory period (A) is the period during which another action potential cannot be initiated, regardless of the strength of the stimulus. The relative refractory period (B) is the period during which another action potential can be initiated if a stronger than normal stimulus is applied. The refractory period also prevents the action potential from spreading back over the part of the membrane that just underwent an action potential (C). Finally, the refractory period places an upper limit on the frequency with which a nerve cell can conduct action potentials (D). Therefore, all of the statements are true.Rate this question:
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- 39.
The relative refractory period of an axon coincides with the period of
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A. activation and inactivation of voltage-dependent Na+ channels.
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B. Na+ permeability that is greater than that during the depolarization phase.
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C. increased K+ flux into the cell.
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D. increased K+ permeability of the cell.
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E. Increased Na+ flux through K+ channels.
Correct Answer
A. D. increased K+ permeability of the cell.Explanation
The relative refractory period of an axon refers to the period of time following an action potential where it is possible for another action potential to be generated, but with a higher threshold. This is due to the increased K+ permeability of the cell, which causes an efflux of potassium ions, leading to hyperpolarization of the cell membrane. This hyperpolarization makes it more difficult for the cell to reach the threshold for generating another action potential. Therefore, option D, increased K+ permeability of the cell, is the correct answer as it accurately describes the mechanism behind the relative refractory period.Rate this question:
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- 40.
The maintenance of a resting potential in a neuron depends indirectly upon the functioning of the Na+, K+-ATPase pumps in the membrane.
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True
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False
Correct Answer
A. TrueExplanation
The resting potential in a neuron is maintained by the Na+, K+-ATPase pumps in the membrane. These pumps actively transport sodium ions out of the neuron and potassium ions into the neuron, creating an electrochemical gradient. This gradient contributes to the negative charge inside the neuron, which is essential for maintaining the resting potential. Therefore, the functioning of the Na+, K+-ATPase pumps indirectly affects the maintenance of the resting potential in a neuron.Rate this question:
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- 41.
The basal ganglia are important subcortical nuclei in the cerebrum.
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True
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False
Correct Answer
A. TrueExplanation
The basal ganglia are indeed important subcortical nuclei in the cerebrum. They play a crucial role in various functions such as movement coordination, motor control, and reward-based learning. They are involved in the regulation of voluntary movements and are interconnected with other parts of the brain, including the cerebral cortex. Therefore, the statement "The basal ganglia are important subcortical nuclei in the cerebrum" is true.Rate this question:
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- 42.
Compartments A and B are separated by a membrane that is permeable to K+ but not to Na+ or Cl-. At time zero, a solution of KCl is poured into compartment A and an equally concentrated solution of NaCl is poured into compartment B. Which would be true once equilibrium is reached?
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A. The concentration of Na+ in A will be higher than it was at time zero.
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B. Diffusion of K+ from A to B will be greater than the diffusion of K+ from B to A.
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C. There will be a potential difference across the membrane, with side B negative relative to side A.
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D. The electrical and diffusion potentials for K+ will be equal in magnitude and opposite in direction.
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E. The concentration of Cl- will be higher in B than it was at time zero.
Correct Answer
A. D. The electrical and diffusion potentials for K+ will be equal in magnitude and opposite in direction.Explanation
Since the membrane is permeable to K+ but not to Na+ or Cl-, K+ will diffuse from compartment A to compartment B until equilibrium is reached. As K+ diffuses, it will create a concentration gradient, causing a diffusion potential. At the same time, the movement of K+ will also create an electrical potential due to the charge of K+. At equilibrium, the electrical and diffusion potentials for K+ will be equal in magnitude but opposite in direction, resulting in no net movement of K+. Therefore, option D is correct.Rate this question:
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- 43.
An action potential does not re-stimulate the adjacent membrane that was previously depolarized because
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A. stimulation is inhibited by the myelin sheath.
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B. it is impossible for an action potential to be propagated along an axon toward the nerve cell body.
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C. the resting membrane potential of the axon is too positive.
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D. the resting membrane potential of the axon is too negative.
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E. that area of the membrane is in the absolutely refractory period.
Correct Answer
A. E. that area of the membrane is in the absolutely refractory period.Explanation
An action potential does not re-stimulate the adjacent membrane that was previously depolarized because that area of the membrane is in the absolutely refractory period. During this period, the voltage-gated sodium channels responsible for generating an action potential are inactivated and cannot be reopened until the membrane potential returns to its resting state. This prevents the action potential from propagating backward and ensures that the signal moves in one direction along the axon.Rate this question:
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- 44.
Which is one of the major inhibitory neurotransmittors in the CNS?
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A. Glutamate
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B. Dopamine
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C. Norepinephrine
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D. Gamma-aminobutyric acid (GABA)
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E. Beta-endorphin
Correct Answer
A. D. Gamma-aminobutyric acid (GABA)Explanation
Gamma-aminobutyric acid (GABA) is one of the major inhibitory neurotransmitters in the central nervous system (CNS). It functions by reducing the activity of neurons, thus inhibiting their ability to send signals. GABA plays a crucial role in regulating brain activity and maintaining a balance between excitatory and inhibitory neurotransmission. It is involved in various processes such as sleep, relaxation, and anxiety regulation. The other options listed, such as glutamate, dopamine, norepinephrine, and beta-endorphin, are not primarily inhibitory neurotransmitters in the CNS.Rate this question:
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- 45.
Which is FALSE about neurons?
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A. A given neuron can be either a presynaptic neuron or a postsynaptic neuron.
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B. An individual neuron can receive information from multiple other neurons.
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C. An individual neuron can transmit information to multiple other neurons.
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D. A neuron can simultaneously release more than one type of neurotransmitter.
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E. A neuron receives information on its axons and delivers it to other neurons through its dendrites.
Correct Answer
A. E. A neuron receives information on its axons and delivers it to other neurons through its dendrites. -
- 46.
The membrane potential of most neurons at rest is:
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A. equal to the equilibrium potential for potassium.
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B. equal to the equilibrium potential for sodium.
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C. slightly more negative than the equilibrium potential of potassium ion.
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D. more positive than the equilibrium potential for potassium.
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E. more positive than the equilibrium potential for sodium.
Correct Answer
A. D. more positive than the equilibrium potential for potassium.Explanation
The resting membrane potential of most neurons is more positive than the equilibrium potential for potassium because the cell membrane is more permeable to potassium ions at rest. This means that there is a higher concentration of potassium ions inside the cell compared to outside, creating an electrochemical gradient that drives potassium ions out of the cell. As a result, the inside of the cell becomes more negative relative to the outside, leading to a resting membrane potential that is more positive than the equilibrium potential for potassium.Rate this question:
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- 47.
Which of the following statements concerning the permeability of a typical neuron membrane at rest is true?
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A. The permeability to Na+ is much greater than the permeability to K+.
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B. All of the K+ channels in the membrane are open.
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C. The voltage-gated Na+ channels are in the inactivated state.
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D. Most of the voltage-gated Na+ channels are in the closed state.
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E. There is equal permeability to Na+ and K+.
Correct Answer
A. D. Most of the voltage-gated Na+ channels are in the closed state.Explanation
At rest, the neuron membrane has a higher permeability to K+ ions than Na+ ions. This is because most of the voltage-gated Na+ channels are in the closed state, preventing the influx of Na+ ions. On the other hand, the K+ channels are mostly open, allowing K+ ions to flow out of the cell. This difference in permeability contributes to the resting membrane potential of the neuron.Rate this question:
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- 48.
The regions of axon membrane that lie between regions of myelin are the
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A. islets of Langerhans.
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B. nodes of Ranvier.
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C. synaptic membranes.
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D. glial cells.
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E. dens of iniquities.
Correct Answer
A. B. nodes of Ranvier.Explanation
The regions of axon membrane that lie between regions of myelin are called nodes of Ranvier. These nodes are small gaps in the myelin sheath where the axon is exposed. They play a crucial role in the conduction of nerve impulses by allowing the electrical signals to jump from one node to another, which speeds up the transmission of the signal along the axon.Rate this question:
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- 49.
Exocytosis of neurotransmitter into the synaptic cleft is triggered by an influx of ______ in response to the arrival of an action potential in the axon terminal.
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A. K+
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B. Na+
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C. Ca2+
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D. ATP
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E. Cl-
Correct Answer
A. C. Ca2+Explanation
Exocytosis is the process by which neurotransmitters are released from the axon terminal into the synaptic cleft. This release is triggered by an influx of calcium ions (Ca2+) in response to the arrival of an action potential. Calcium ions play a crucial role in the fusion of synaptic vesicles containing neurotransmitters with the cell membrane, allowing the neurotransmitters to be released into the synaptic cleft and bind to receptors on the postsynaptic neuron. Therefore, the correct answer is C. Ca2+.Rate this question:
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Mar 22, 2023Quiz Edited by
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Apr 13, 2019Quiz Created by
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