Pearson's Lab #7 & Ch. 7,8,8a
Which membrane potential opens a sufficient number of the voltage-gated Na+ channels to cause a significant change in the membrane potential (making it much less negative).
-60 mV
A neuron has a resting potential of about _____ millivolts.
-70
What is the resting membrane potential of the neuron used in the experiment?
-80 mV
What is the magnitude (amplitude) of an action potential?
100 mV
What is the difference between a reflex and a reflex arc?
A reflex is an automatic response; a reflex arc is the neural circuitry.
Which term describes an electrical signal generated by neurons?
Action potential.
Which of the following statements is FALSE regarding proteins?
Alzheimer's disease causes proteins in the brain to become improperly folded.
Which of the following best describes Alzheimer's disease?
Alzheimer's is a neurological disease with loss of memory and motor skills.
Which of the following statements about the stimulation of muscle cells is true?
An action potential in a muscle cell ultimately results in the release of calcium ions into the cell.
Why are many muscles at the effector end of the reflex arc found in antagonistic pairs?
Antagonistic muscles have opposite actions. This is often needed for a reflex.
A nerve impulse moves away from a neuron's cell body along _____.
Axon
What occurs when the action potential reaches the synaptic terminal?
Calcium ions rush into the presynaptic terminal.
Which part of the brain is associated with conscious thought, memory, and personality?
Cerebral cortex
Which of the following terms describes how a neuronal membrane's potential is altered in the presence of inhibitory signals?
Hyperpolarization.
Consider the neurotransmitters norepinephrine and acetylcholine. Which statement is generally true?
In general, the neurotransmitter of the sympathetic nervous system is norepinephrine, and the neurotransmitter of the parasympathetic nervous system is acetylcholine.
How does cardiac muscle differ from the other types of muscle?
It contains branched cells.
Which statement accurately describes the myelin sheath?
It speeds up the conduction of nervous impulses.
Multiple sclerosis is a disease in which the myelin sheath is destroyed. What will happen to nerve conduction speed in affected neurons?
It will slow down dramatically.
Resting neurons are most permeable to which of the following ions?
K+.
The membranes of neurons at rest are very permeable to _____ but only slightly permeable to _____.
K+; Na+
Which of the following drugs is most similar in mode of action and effect to ecstasy?
LSD
Which of the following will increase the rate of alcohol metabolism?
Liver metabolism cannot be increased.
Which term describes the difference in electrical charge across a membrane?
Membrane potential.
Marina has owned a bar for many years and extols the health benefits of alcohol. Which of these claims is correct?
Moderate consumption raises the "good" cholesterol levels.
Which structure is not part of a neuron?
Myelin sheath.
Which of the following interactions is the molecular basis of muscle contraction?
Myosin and thin filaments.
Which molecules form the thick filaments of sarcomeres?
Myosin.
The concentrations of which two ions are highest outside the cell.
Na+ and Cl-
The Na+-K+ pump actively transports both sodium and potassium ions across the membrane to compensate for their constant leakage. In which direction is each ion pumped?
Na+ is pumped out of the cell and K+ is pumped into the cell.
When talking about the movement of neurotransmitters, what can we accurately say?
Neurotransmitters are released by one neuron, diffuse across a gap, and bind to receptor sites on another cell membrane, triggering a change in the activity of the receptor cell.
Which channel is mainly responsible for the resting potential of a neuron?
Potassium leak channel.
What does saltatory conduction mean?
Saltatory conduction means that the nerve impulse seems to jump from one node to the next—and is regenerated as it speeds along.
What type of cell makes up the myelin sheath of a motor neuron?
Schwann cells
When speaking of myelinating glial cells, we can correctly say that ________.
Schwann cells are glial cells found outside the brain and spinal cord; oligodendrocytes are glial cells found in the brain and spinal cord
Which of the following events is the first to occur during an action potential?
Sodium channels open.
How is an action potential propagated down an axon after voltage-gated sodium channels open in a region of the neuron's membrane?
Sodium ions enter the neuron and diffuse to adjacent areas, resulting in the opening of voltage-gated sodium channels farther down the axon.
Which of the following statements is true about the interaction of sympathetic and parasympathetic nerve fibers?
Sympathetic and parasympathetic nerve fibers may innervate the same organs, but they have generally opposite effects.
What is the active drug in marijuana?
THC
What causes an action potential to be conducted along a neuron's axon?
The change in charge difference across the membrane spreads from open sodium channels, causing sodium channels farther along the axon to open.
A certain drug prevents a neurotransmitter from initiating a response in the receiving neuron. Which of the following statements best describes the mechanism by which the drug may be acting?
The drug is preventing the neurotransmitter from binding to its receptors in the receiving neuron.
Which event triggers the creation of an action potential?
The membrane depolarizes above a certain threshold potential.
You just cut yourself. Which statement best explains how the spinal cord is involved?
The message goes from the cut via the sensory fibers to the dorsal root of the spinal cord. The motor response message exits the spinal cord via the ventral root.
A new drug interferes with the function of the dendrites of a neuron. What will happen to this neuron?
The neuron cannot be stimulated to send a signal along its axon.
When the neurotransmitter crosses the synapse, what happens?
The neurotransmitter causes the channel to open, and this can cause a depolarization of the postsynaptic membrane.
Which step constitutes the power stroke of muscle contraction?
The phosphate ion is released, and the myosin head moves back to its original position.
What behavior is observed if the voltage across a neuronal membrane is set to -20 mV?
The sodium channel opens, and Na+ ions flow in.
Which channel maintains the concentration gradients of ions across a neuronal membrane?
The sodium-potassium pump moving Na+ ions out and K+ ions in.
Which of the following statements most accurately describes the spinal cord?
The spinal cord takes messages to and from the brain and functions as a reflex center.
Which statement most accurately describes the relative physical position of the ganglia of the sympathetic and parasympathetic nervous systems?
The sympathetic ganglia are located in chain-like fashion near the spinal cord. The parasympathetic ganglia are located closer to their target organs.
Think of the heart in the tutorial. Now, picture yourself being chased by a herd of wild elephants. What are the sympathetic and parasympathetic actions on your heart?
The sympathetic nervous system will cause the heart rate to speed up. The parasympathetic nervous system will be "overridden."
Which of these statements best describes a synapse?
The synapse includes the space between the presynaptic membrane and the postsynaptic membrane.
Which of the following statements is correct?
There is a correlation between beta-amyloid plaques and the severity of Alzheimer's disease.
Sodium and potassium ions cross the neuron's membrane to cause which of the following processes?
action potential
What is the mechanism of action of nicotine?
activates acetylcholine receptors
During an action potential, when does sodium ion permeability begin to significantly decline?
at the peak of depolarization
An action potential moves along a(n) _____.
axon
Where in the neuron do action potentials begin?
axon hillock
Where in the neuron is an action potential initially generated?
axon hillock
The part of the nerve cell responsible for origination of the nerve impulse is the ________.
axon hillock, because this is the specific area of the nerve cell that generates the electrical impulse that travels along the axon
Name the three principal parts of the nerve cell.
axon, dendrites, cell body
During depolarization, which gradient(s) move(s) Na+ into the cell?
both the electrical and chemical gradients
The release of _____ ions from the sarcoplasmic reticulum is required for skeletal muscle contraction.
calcium
A neuron's nucleus is located in its _____.
cell body
Binding of the neurotransmitter to its receptor causes the membrane to __________.
either depolarize or hyperpolarize
Which set of words can correctly be used to describe interneurons?
excitatory and inhibitory
Which brain structure maintains homeostasis and influences blood pressure, heart rate, digestive activity, breathing rate, and body temperature?
hypothalamus
Which drug, if it were legal, would you recommend for a patient who has little or no appetite, such as a person on chemotherapy?
marijuana
Ivana has a rapidly growing brain tumor and must be put on life support because she can no longer maintain appropriate heart and respiratory rates. She is also having trouble maintaining blood pressure. The most likely area that the tumor is affecting is the ________.
medulla oblongata
Which of the following is a chemical signal that diffuses across the gap between adjacent neurons to convey a message to the next cell?
neurotransmitter
A molecule that carries information across a synaptic cleft is a
neurotransmitter.
The transmission first triggers the _____.
opening of voltage-gated sodium channels and the diffusion of sodium ions into the neuron
When you ride your bike to class, which area of the cerebrum are you using to move your leg muscles?
premotor cortex
In a synapse, neurotransmitters are stored in vesicles located in the __________.
presynaptic neuron
Which of the following is the correct sequence for the electrical transmission of a nerve impulse?
presynaptic neuron, synapse, postsynaptic neuron
A psychoactive drug that delays the removal of a neurotransmitter from the synapse will ________.
prolong the effect of the neurotransmitter on the receiving neuron
Part complete Drugs that alter one's mood or emotional state are called __________.
psychoactive
Which muscle type is involved in the function of the digestive tract and blood vessels?
smooth
Which one of the following ions outside the neuron would make it very difficult for a depolarization to occur?
sodium
A stimulus has opened the voltage-gated sodium channels in an area of a neuron's plasma membrane. As a result, _____ rushes into the neuron and diffuses to adjacent areas; this in turn results in the _____ in the adjacent areas.
sodium ... opening of voltage-gated sodium channels
The space between an axon of one neuron and the dendrite of another neuron is called a(n) _____.
synaptic cleft
Which of these structures is located under the cerebral hemispheres and is important in sensory experience, motor activity, stimulation of the cerebral cortex, and memory?
thalamus
Complete this sentence. The CNS communicates with the body proper through ________.
the cranial nerves and the spinal nerves
During an action potential
the inside of the neuron becomes positively charged relative to the outside.
In a resting nerve cell membrane (think axon), the electrical relationship between the fluid inside the membrane (inside the cell) and the fluid outside the membrane (extracellular fluid) is as follows: ________.
the interior is negative relative to the exterior
During the course of muscle contraction the potential energy stored in ATP is transferred to potential energy stored in _____.
the myosin head
The repolarization phase of an action potential results from __________.
the opening of voltage-gated K+ channels
When discussing the origins of the sympathetic and parasympathetic divisions of the autonomic nervous system, we can most correctly state that ________.
the parasympathetic nerves arise from the brain and part of the spinal cord, and all of the sympathetic nerves arise from the spinal cord
If a signal from a sending neuron makes the receiving neuron more negative inside,
the receiving neuron is less likely to generate an action potential.
When a neuron is at its resting potential
there are more potassium ions inside the neuron than outside.
The depolarization phase of an action potential results from the opening of which channels?
voltage-gated Na+ channels
As an action potential moves along an axon, we could say that ________.
when the signal first reaches the axon, the sodium channels open and the sodium ions move down a concentration gradient
In saltatory conduction, nerve impulses jump from one exposed region of the axon to another. This exposed region is called the ________.
node of Ranvier
An impulse relayed along a myelinated axon "jumps" from _____ to _____.
node of Ranvier ... node of Ranvier
Hyperpolarization results from __________.
slow closing of voltage-gated K+ channels
What part of a neuron relays signals from one neuron to another neuron or to an effector?
synaptic terminal
Neurons store neurotransmitter molecules in vesicles located within _____.
synaptic terminals
When calcium ions enter the synaptic terminal,
they cause vesicles containing neurotransmitter molecules to fuse to the plasma membrane of the sending neuron.
Why does the story in the video start in Colombia?
There is an extended family with inherited early onset Alzheimer's in Colombia, and family members with the gene can be participants in a drug trial to reduce plaques.
Which of the following statements about action potentials in a given neuron is false?
They are propagated down the length of the dendrite.
Illegal drugs gain their popularity because they primarily affect which portion of the brain?
limbic system
Which of the following can be defined as a collection of structures involved in emotions and memory?
limbic system
A very deep groove that runs between the right and left cerebral hemispheres is called the ________.
longitudinal fissure
Which of the following is not a potential effect of alcohol abuse?
lung cancer
The small space between the sending neuron and the receiving neuron is the
synaptic cleft.
If a person uses Percocet, a morphine relative, to which of these drugs might that person develop cross-tolerance?
heroin
Gustav heard that a new sports drink would bulk up his muscles. He was worried that the stuff would contain steroids but was assured by his coach that it did not. He tried small amounts at first but then became impatient for results and drank a lot. He collapsed and was rushed to the emergency room with a high temperature. Using the information in this chapter, which part of the brain was most affected?
hypothalamus
When neurotransmitter molecules bind to receptors in the plasma membrane of the receiving neuron,
ion channels in the plasma membrane of the receiving neuron open.
Repolarization __________.
is due to movement of potassium ions out of the axon
The peripheral nervous system (PNS) transmits information to and from the central nervous system (CNS) and plays a role in regulating an animal's movements and internal environment. Determine which of the following statements about the PNS are true.
- The sympathetic division of the PNS prepares the body for physical exertion in stressful situations. - Neurons in the parasympathetic division release neurotransmitters that act on receptors that slow heart rate. - Parasympathetic nerves are associated with the cranial and sacral regions of the spinal cord, whereas sympathetic nerves are associated with the thoracic and lumbar regions. - Stimulating the organs of digestion is a parasympathetic response.
What is the value for the resting membrane potential for most neurons?
-70 mV
Blood alcohol level is solely dependent upon the number of drinks consumed.
False
Dependence is a progressive decrease in the effectiveness of a drug in a given person.
False
Heroine is an opiate that works primarily by increasing the levels of dopamine and serotonin in the brain.
False
It has been proven that using marijuana leads to use of more serious drugs.
False
One advantage to amphetamines is that they are NOT addictive.
False
True or false. An individual who has suffered a stroke, which has caused damage in his cerebrum, and is now having problems with his hearing, has probably suffered damage to his occipital lobe.
False
True or false? Action potentials travel in only one direction down an axon because potassium channels in the neuron are refractory and cannot be activated for a short time after they open and close.
False
True or false? The potential energy of a membrane potential comes solely from the difference in electrical charge across the membrane.
False
As an action potential is propagated and the voltage-regulated ion gates open and close, what happens?
First the membrane polarity is reversed and then the ions return to their normal electrical state.
Infants require many nutrients early in life, including lipids such as fats. A low-fat diet for infants is not recommended because, among other things, it can affect the development of the nervous system. Why does the developing nervous system need lipids?
Glial cells need lipids to produce the myelin sheath.
Infants require many nutrients early in life, including lipids such as fats. A low-fat diet for infants is not recommended because, among other things, it can impact the development of the nervous system. Why does the developing nervous system need lipids?
Glial cells need lipids to produce the myelin sheath.
Your neighbor tried to lift a propane tank onto the back of his pickup truck and ruptured the cartilaginous disk between two of his vertebrae. What is most likely to happen to him?
He will suffer pain from a compressed spinal nerve.
According to the video, which of the following describes the impact of Alzheimer's in the United States by the year 2050?
It is projected that there will be 16 million cases by 2050, with an annual health care cost of $1 trillion.
Think about the experimental design of the drug trial described in the essay. Should everyone in the drug trial receive the drug being tested?
No, because there should be a control group that receives a placebo instead of the drug.
Which of the following is a difficult ethical consideration in a drug trial like the one described here, and accurately describes Natasha's (Marta's daughter's) perspective in the video?
Not everyone wants to know if they are carrying a gene that will eventually cause a horrible disease.
Which statement is most correct about the activities of psychoactive drugs?
Psychoactive drugs may either increase or decrease the response of the receptor.
Which part of the brain functions as a relay station for information to the limbic system and the cerebral cortex?
Thalamus
Which of the following is the most correct statement about psychoactive drugs and neurotransmitters?
The first three answers are all correct. Psychoactive drugs can increase the number of neurotransmitter molecules; they can decrease the number of neurotransmitter molecules; and they can bind to the neurotransmitter receptor sites.
Regarding the gray matter and the white matter of the spinal cord, which statement is most accurate?
The gray matter is unmyelinated and is composed of cell bodies and dendrites. The white matter is myelinated and is composed of axons.
Which statement correctly describes the number and functional location of the cranial and spinal nerves?
There are 12 pairs of cranial nerves. Some are sensory, some are motor, and some are sensory and motor. Most function only in the head, but two also function in the body proper. There are 31 pairs of spinal nerves. All have both sensory and motor components, and all function in the body proper.
Which of the following is NOT a method for clearing neurotransmitters from a synapse?
They can be taken up into the postsynaptic neuron.
Amphetamines are drugs that can bind to the same receptors as the neurotransmitter norepinephrine and can also inhibit the enzymes that break down norepinephrine. Based on this information, which of the following effects would amphetamines most likely have on norepinephrine action?
They produce the same effects as norepinephrine for a prolonged period of time.
Alcoholism is America's number one drug problem.
True
Moderate alcohol consumption can actually increase the blood levels of good cholesterol, or HDL.
True
The mechanism by which the neurotransmitter is returned to a presynaptic neuron's axon terminal is specific for each neurotransmitter. Which of the following neurotransmitters is broken down by an enzyme before being returned?
acetylcholine
A nerve impulse does not vary in intensity with regard to the strength of the stimulus. This is known as what principle?
all-or-nothing principle
Which of these causes the release of neurotransmitter molecules?
an action potential reaching the end of the axon
An action potential would most commonly arrive from which of the following structures before arriving at the axon?
cell body
You are watching a football game with your friends. A wide receiver makes an incredible catch and then runs 20 yards, skillfully dodging defensive players to make a touchdown. Your friend Joe says, "Amazing! How does he do that?" The receiver's outstanding sensory-motor coordination is largely due to the actions of his __________.
cerebellum
Binding of a neurotransmitter to its receptors opens __________ channels on the __________ membrane.
chemically gated; postsynaptic
While examining her patient's nose, Dr. Carlita Gonzales, an allergy specialist, noted a hole in the partition between the nasal cavities. The doctor suspects her patient is snorting which drug?
cocaine
Belinda was riding a bicycle without a helmet and was struck by a car. She hit the back of her head very hard in the fall. The physician is quite concerned because the medulla is located at the base of the skull. She explains to Belinda's parents that injury to the medulla could result in __________.
death, because many life-support systems are controlled here
A nerve impulse moves toward a neuron's cell body along _____.
dendrites
True or false? Myofibrils are the alternating light-dark units that produce the banded appearance of muscle fibers.
false
Neurons with a myelin sheath carry impulses __________ unmyelinated cells.
faster than
During an automobile accident, Susan received a serious head injury to the left side. Afterward she had a hard time speaking, although she showed that she understood what was being said to her. Which area of her cerebrum was damaged?
frontal lobe
This 1-inch section of the brain controls the breathing rhythm and heart rate.
medulla oblongata
Which of the following parts of the nervous system is closest to a muscle?
motor neuron
Which of these diseases involves the destruction of the myelin sheath on certain neurons within the brain and spinal cord?
multiple sclerosis
You might have been accidentally exposed to an insecticide while working in a citrus grove. What symptoms of poisoning would you watch for?
muscle tremors
Axons insulated by a(n) _____ are able to conduct impulses faster than those not so insulated.
myelin sheath
Which of the following is a specific function of the cerebrospinal fluid?
shock absorption
A neuron's membrane that maintains a charge difference across its surface in which the inside is more negative than the outside is called ________.
resting potential
Sodium-potassium pumps
restore the distribution of ions inside and outside a neuron's membrane following an action potential.
You are generally not aware of the texture of the cloth of your shirt as it rests on your shoulders, unless someone or something happens to make you think of it. What part of the brain is responsible for filtering out such stimuli?
reticular activating center
As you sit here studying, you are unlikely to be aware of the pressure of your clothes against your body and the rustling of paper as other students turn pages. Which part of the brain "decides" that these are unimportant stimuli?
reticular activating system
You touch a hot stove and your hand quickly jerks away. What is the path of the nerve impulses that are responsible for this reflex?
sensory neuron to interneuron to motor neuron
Which component of a reflex arc carries information to the central nervous system?
sensory neurons
In the propagation of an action potential, which voltage-regulated gates open first?
sodium gates
The specialized membrane proteins that actively transport sodium and potassium ions across the plasma membrane are known as the ________.
sodium-potassium pump
In this experiment, which stimulus causes the membrane potential to reach the threshold value?
stimulus 3
The combined effects of inhibitory and excitatory effects on a postsynaptic cell will decide whether that cell generates an action potential. This principle is called ________.
summation
If someone were to yell, "Fire!" now and you suddenly began to smell smoke, which part of your nervous system would become activated to prepare your internal body systems to deal with the dangerous situation?
sympathetic system
Of these events, the first to occur when a motor neuron stops sending an impulse to a muscle is _____.
the pumping of calcium ions out of the cytoplasm and back into the sarcoplasmic reticulum
During an action potential, the rapid decrease in sodium ion permeability and the simultaneous and rapid increase in potassium ion permeability is responsible for __________.
the repolarization phase
The role of the sodium-potassium pump in the story of the action potential is as follows: ________.
the sodium-potassium pump functions in returning the membrane to its "normal" state after an action potential has been propagated
At rest, which of these plays a role in establishing the charge differential across a neuron's plasma membrane?
the sodium-potassium pump moving sodium ions out of the neuron and potassium ions into the neuron
Myosin heads bind to _____, which they then pull and cause to slide toward the center of the sarcomere.
thin filaments
An action potential releases neurotransmitter from a neuron by opening which of the following channels?
voltage-gated Ca2+ channels
