03:37Animation: Propagation of an Action Potential in Unmyelineated and Myelinated AxonsPearson1710views1rank
03:31Neurotransmitters And Their Functions Dopamine, Glutamate, Serotonin, Norepinephrine, EpinephrineProfessional Supplement Center463views
02:06Definition of neurotransmitters / classification of NeurotransmitterZeal's pharmacy tutorials762views
10:57The Nervous System, Part 3 - Synapses!: Crash Course Anatomy & Physiology #10CrashCourse811views
05:33Factors affecting the speed of an Action Potential: The Speed of Conductance Along an Axon.Miss Estruch866views
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Multiple ChoiceA neuron that transmits an impulse to the central nervous system after the neuron is stimulated by the environment is called a(n) __________. 638views
Multiple ChoiceWhich of the following is specifically a part or a function of the central nervous system? 498views
Multiple ChoiceThe part of a neuron that carries nerve impulses toward the cell body is called a(n) __________. 632views
Multiple ChoiceCells that provide metabolic and structural support to the neurons are called __________. 465views
Multiple ChoiceIf your fingers touch a hot stove and you suddenly pull back, you have experienced a reflex. What is the correct order of the information processing in this reflex? 388views
Multiple ChoiceIn descriptions of synapse organization, which type of cell is the transmitting neuron, and which type of neuron, muscle, or gland cell receives the signal? 482views
Multiple ChoiceThe interplay of multiple excitatory and inhibitory inputs most affects what part of a neuron? 414views
Multiple ChoiceWhich of the following is a mechanism by which neurotransmitters can be rapidly cleared from the synaptic cleft? 1206views
Multiple ChoiceWhich of the following correctly pairs up a type of synapse and its characteristic? 411views
Multiple ChoiceIn humans, making more serotonin available to brain cells typically __________. 458views
Multiple ChoiceAcetylcholinesterase is the enzyme that degrades acetylcholine. What effect on nerve transmission would occur following the administration of a chemical that inhibited acetylcholinesterase? 1129views
Multiple ChoiceWhich of the following statements about the transmission across a typical chemical synapse is true? 598views
Multiple ChoiceHow are neurons structurally adapted to chemically transmit impulses to neighboring neurons? 1038views
Multiple ChoiceThe period in which an axon membrane cannot generate an action potential is called __________. 400views
Multiple ChoiceBlocking potassium ion channels in a mammalian cell membrane would __________. 545views
Multiple ChoiceA drug that causes potassium to leak out of a neuron, increasing the positive charge on the outside, would __________. 837views
Multiple ChoiceThreshold is of great significance in the physiology of neurons. What happens if threshold is not reached? 462views
Multiple ChoiceWhich of the following is caused by the death of specific neurons in the brain that release dopamine? 310views
Multiple ChoiceTaking illegal amphetamines ("speed") can induce symptoms similar to which of the following? 300views
Multiple ChoiceWhich of the following neurotransmitters is most closely associated with schizophrenia, addiction, and Parkinson's disease? 482views
Textbook QuestionWhat happens when a resting neuron's membrane depolarizes? a. There is a net diffusion of Na+ out of the cell. b. The equilibrium potential for K+(EK) becomes more positive. c. The neuron's membrane voltage becomes more positive. d. The cell's inside is more negative than the outside.1379views
Textbook QuestionTest your understanding of the nervous system by matching the following labels with their corresponding letters: CNS, effector cells, interneuron, motor neuron, PNS, sensory neuron, sensory receptor, spinal cord, synapse. 822views
Textbook QuestionWhich ion most readily leaks across a neuron's membrane, helping to establish the resting potential?495views
Textbook QuestionA common feature of action potentials is that they a. cause the membrane to hyperpolarize and then depolarize. b. can undergo temporal and spatial summation. c. are triggered by a depolarization that reaches threshold. d. move at the same speed along all axons.970views
Textbook QuestionThe inside of the neuron has a lower concentration of positive ions than the outside of the neuron. Is the membrane potential positive or negative?543views
Textbook QuestionWhich of these statements about myelination in neurons is/are correct? Select True or False for each statement. T/F It speeds propagation by increasing the density of voltage-gated channels all along the axon. T/F Multiple sclerosis is characterized by disrupted myelination of certain neurons in the central nervous system. T/F It speeds propagation by preventing cations from leaking out across the membrane as they spread down the axon. T/F It is more commonly observed in vertebrates than in invertebrates.682views
Textbook QuestionWhere are neurotransmitter receptors located? a. the nuclear membrane b. the nodes of Ranvier c. the postsynaptic membrane d. synaptic vesicle membranes1473views
Textbook QuestionIn a neuron, what creates the electrochemical gradient favoring the outflow of K+ when the cell is at rest? a. Na+/K+-ATPase b. voltage-gated K+ channels c. voltage-gated Na+ channels d. ligand-gated Na+/K+ channels518views
Textbook QuestionWhy are action potentials usually conducted in one direction? a. Ions can flow along the axon in only one direction. b. The brief refractory period prevents reopening of voltage-gated Na+ channels. c. The axon hillock has a higher membrane potential than the terminals of the axon. d. Voltage-gated channels for both Na+ and K+ open in only one direction.2005views
Textbook QuestionWhat causes a nerve signal to move from one end of a neuron along the length of the neuron to the other end? What is a nerve signal, exactly? Why can't it go backward? How is a nerve signal transmitted from one neuron to the next across a synapse? Write a short paragraph that answers these questions.324views
Textbook QuestionWhich of the following is the most direct result of depolarizing the presynaptic membrane of an axon terminal? a. Voltage-gated calcium channels in the membrane open. b. Synaptic vesicles fuse with the membrane. c. Ligand-gated channels open, allowing neurotransmitters to enter the synaptic cleft. d. An EPSP or IPSP is generated in the postsynaptic cell.914views
Textbook QuestionExplain the difference between a ligand-gated K+ channel and a voltage-gated K+ channel.425views
Textbook QuestionSuppose a particular neurotransmitter causes an IPSP in postsynaptic cell X and an EPSP in postsynaptic cell Y. A likely explanation is that a. the threshold value in the postsynaptic membrane is different for cell X and cell Y. b. the axon of cell X is myelinated, but that of cell Y is not. c. only cell Y produces an enzyme that terminates the activity of the neurotransmitter. d. cells X and Y express different receptor molecules for this particular neurotransmitter.644views
Textbook QuestionAnesthetics block pain by blocking the transmission of nerve signals. Which of these three chemicals might work as anesthetics? (Choose all that apply and explain your selections.) a. a chemical that prevents the opening of voltage-gated Na+ channels in membranes b. a chemical that inhibits the enzymes that degrade neurotransmitters c. a chemical that blocks neurotransmitter receptors402views
Textbook QuestionSCIENTIFIC THINKING A proposal to test an SSRI in a large number of individuals with depression was submitted to the FDA. Through random assignments, half of the patients would be controls, receiving nothing at all, and half the patients would receive the drug in pill form. Patients in both groups would note changes in their own mood in a daily journal. What flaw(s) do you note in this experimental design?242views
Textbook QuestionUsing microelectrodes, a researcher recorded nerve signals in four neurons in the brain of a snail, called A, B, C, and D in the table below. A, B, and C can all transmit signals to D. In three experiments, the animal was stimulated in different ways. The number of nerve signals transmitted per second by each of the cells is recorded in the table. Write a short paragraph explaining the different results of the three experiments. 335views
Textbook QuestionExplain why drugs that prevent neurotransmitters from being taken back up by a presynaptic neuron have dramatic effects on the activity of postsynaptic neurons.425views
Textbook QuestionCertain species of frogs in the genus Phyllobates have a powerful defensive adaptation—their skin can secrete a milky fluid that contains an extremely toxic compound called batrachotoxin (BTX). These frogs, which are found in Colombia, are known as poison dart frogs because some indigenous Colombian hunters coat the tips of their blowgun darts with the frogs' skin secretions. An animal hit by one of these darts dies quickly. What is the mechanism of action of BTX? The graph here shows the effect of BTX on the membrane potential of a squid giant axon. Which of the following is the most likely explanation for the effect of BTX on the squid giant axon? a. inactivation of Na+/K+-ATPase b. closing of sodium channels c. opening of sodium channels d. opening of potassium channels474views
Textbook QuestionCertain species of frogs in the genus Phyllobates have a powerful defensive adaptation—their skin can secrete a milky fluid that contains an extremely toxic compound called batrachotoxin (BTX). These frogs, which are found in Colombia, are known as poison dart frogs because some indigenous Colombian hunters coat the tips of their blowgun darts with the frogs' skin secretions. An animal hit by one of these darts dies quickly. What is the mechanism of action of BTX? Identify a research technique that could be used to discover how BTX affects specific membrane proteins. Based on the graph in Question 11, what would you expect this technique to show?271views
Textbook QuestionCertain species of frogs in the genus Phyllobates have a powerful defensive adaptation—their skin can secrete a milky fluid that contains an extremely toxic compound called batrachotoxin (BTX). These frogs, which are found in Colombia, are known as poison dart frogs because some indigenous Colombian hunters coat the tips of their blowgun darts with the frogs' skin secretions. An animal hit by one of these darts dies quickly. What is the mechanism of action of BTX? As the graph in Question 11 shows, BTX depolarizes the membrane and prevents repolarization. What effect would this have on electrical signaling by the nervous system?309views
Textbook QuestionCertain species of frogs in the genus Phyllobates have a powerful defensive adaptation—their skin can secrete a milky fluid that contains an extremely toxic compound called batrachotoxin (BTX). These frogs, which are found in Colombia, are known as poison dart frogs because some indigenous Colombian hunters coat the tips of their blowgun darts with the frogs' skin secretions. An animal hit by one of these darts dies quickly. What is the mechanism of action of BTX? Like neurons, cells in skeletal and cardiac muscle also produce action potentials. Create a concept map showing how BTX could kill a mammal through its effects on nervous and muscle tissues.306views
Textbook QuestionCertain species of frogs in the genus Phyllobates have a powerful defensive adaptation—their skin can secrete a milky fluid that contains an extremely toxic compound called batrachotoxin (BTX). These frogs, which are found in Colombia, are known as poison dart frogs because some indigenous Colombian hunters coat the tips of their blowgun darts with the frogs' skin secretions. An animal hit by one of these darts dies quickly. What is the mechanism of action of BTX? Predict the effects of each of the following on the membrane potential of a neuron simultaneously poisoned with BTX: (a) removing extracellular sodium ions; (b) increasing the intracellular potassium ion concentration; and (c) adding tetrodotoxin from puffer fish.343views
Textbook QuestionCertain species of frogs in the genus Phyllobates have a powerful defensive adaptation—their skin can secrete a milky fluid that contains an extremely toxic compound called batrachotoxin (BTX). These frogs, which are found in Colombia, are known as poison dart frogs because some indigenous Colombian hunters coat the tips of their blowgun darts with the frogs' skin secretions. An animal hit by one of these darts dies quickly. What is the mechanism of action of BTX?Although BTX is a powerful antipredator poison, one snake species in Colombia eats poison dart frogs. Suggest a hypothesis that might explain how the snake is resistant to the toxin.327views