Loose Leaf For Integrated Principles Of Zoology
18th Edition
ISBN: 9781260411140
Author: Cleveland P Hickman Jr. Emeritus, Susan L. Keen, David J Eisenhour Professor PhD, Allan Larson, Helen I'Anson Associate Professor of Biology
Publisher: McGraw-Hill Education
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Textbook Question
Chapter 33, Problem 2RQ
Glial cells far outnumber neurons and contribute roughly half the weight of the mammalian nervous system. What functions do glial cells perform in the peripheral nervous system and in the central nervous system?
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Which of the following is NOT a characteristic of the function of the vertebrate nerve cell/ nervous system?
a) nerve cells keep the levels of Na + and k+ AT Equilibrium on both sides of the cell membrane at all times
b) Nerve cells produce impulses that release neurotransmitters to stimulate other cells
C) Nerve cells generate motor output (movement)
d) nerve cells use neurotransmitters to regulate other cells
e)nerve cells are speacialized in employing specific receptors to react to a specific stimulus
The giant squid axon has a diameter = 1mm and 1 = 13mm. Compared to a mammalian neuron with a diameter = 1 um and ^ = 0.2mm, which of the following is correct?
graded potentials can generate action potentials in the mammalian axon but not in the squid axon.
graded potential of similar magnitude would result in action potentials with larger amplitude in the mammalian axon
graded potentials of similar magnitude would result in action potentials with larger amplitude in the squid axon
graded potentials of similar magnitude would travel furthest from their point of origin in the mammalian axon
graded potentials of similar magnitude would travel furthest from their point of origin in the squid axon
Which of the following would you NOT expect with respect to variation in neural conduction velocity?
Neural conduction speed increases over developmental time as Schwann cells synthesize myelin sheaths, insulating neurons
Neural conduction velocity is higher in invertebrate species with insulating sheaths functionally equivalent to vertebrate myelin
Neurons and species with larger axon diameters should have greater conduction velocities
Neural networks with greater serial processing (i.e., lines of connecting neurons) should have greater neural conduction velocities.
The thyroid hormones (triiodothyronine and thyroxine) have a range of roles in regulating growth and metabolism. Thyroid hormones act throughout the body to regulate protein synthesis, long bone growth, and neural maturation. This represents an ______ effect of thyroid hormones. At the same time, through some unknown mechanism, application of thyroid hormones results in an immediate reduction in body temperature, which…
Chapter 33 Solutions
Loose Leaf For Integrated Principles Of Zoology
Ch. 33 - Define the following terms: neuron, axon,...Ch. 33 - Glial cells far outnumber neurons and contribute...Ch. 33 - The concentration of potassium ions inside a nerve...Ch. 33 - What ionic and electrical changes occur during...Ch. 33 - Explain different ways in which invertebrates and...Ch. 33 - Why is the sodium-potassium pump indirectly...Ch. 33 - Prob. 7RQCh. 33 - Prob. 8RQCh. 33 - Prob. 9RQCh. 33 - Prob. 10RQ
Ch. 33 - Prob. 11RQCh. 33 - Prob. 12RQCh. 33 - Prob. 13RQCh. 33 - Prob. 14RQCh. 33 - Chemoreception in vertebrates and insects is...Ch. 33 - What is the vomeronasal organ and what activity...Ch. 33 - Explain how ultrasonic detectors of certain...Ch. 33 - Outline the place theory of pitch discrimination...Ch. 33 - Explain how the semicircular canals of the ear are...Ch. 33 - Contrast the structure and functioning of the...Ch. 33 - Explain what happens when light strikes a...Ch. 33 - Prob. 22RQCh. 33 - Prob. 1FFT
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- Conduction velocity refers to the [a] at which an action potential travels along a neuron's axon. In invertebrates, conduction velocity can only be increased by [b]. However in vertebrates (exclusively), such as humans, conduction velocity can also be increased by [c]. This enables vertebrates to conserve [d] while still increasing conduction velocity. [a] [b] [c] [d] [Choose ] [Choose ] [Choose ] [Choose ]arrow_forwardA neuron of the median giant fiber of an earthworm would respond to an increased intensity of a stimulus by: Increasing the amplitude of action potentials generated Increasing its resting membrane potential Increasing the frequency of action potentials generated Increasing the conduction velocity of action potentials generatedarrow_forwardImagine that scientists have just discovered a weird new marine tunicate at extreme depths of the ocean. They have a novel kind of neurotransmitter – maritonin – that binds to the “maritonin” receptor, which is permeable to negatively charged iodine ions (which are high concentration in seawater and in the extracellular fluid of this species). What do you predict would happen to the postsynaptic neuron when maritonin is released? Depolarization of the postsynaptic cell, increasing the chance of an action potential Hyperpolarization of the postsynaptic cell, decreasing the chance of an action potential Depolarization of the postsynaptic cell, decreasing the chance of an action potential Hyperpolarization of the postsynaptic cell, increasing the chance of an action potential In a central pattern generator, the pacemaker neural cells both have inhibitory inputs on each other. This is key for preventing opposing muscles from contracting at the same time (e.g., if your biceps and…arrow_forward
- The venom of many cobras contains a potent neurotoxin that binds to ligand-gated Na+ channels,causing them to open. Unlike ACh, which binds to and then rapidly unbinds from ligand-gated Na+ channels, the neurotoxin tends to remain bound to ligand-gated Na+ channels. How does this neurotoxin affect the nervous system’s ability to stimulate skeletal muscle contraction? How does it affect the ability of skeletal muscle fibers to respond to stimulation?arrow_forwardHelp mearrow_forwardConsider a typical mammalian neuron with all of the appropriate membrane channels. If you know that neuron is at rest, at a temperature of 37°C and you know the intracellular and extracellular concentration of the potassium, which of the following statements is most likely to be true? a. The equilibrium potential of potassium would be negative if the concentration of potassium is higher on the inside. b. The equilibrium potential of potassium would be positive if the concentration of potassium is higher on the inside c. The equilibrium potential of potassium cannot be calculated because the Nernst equation requires that you know the concentration of all ions d. The equilibrium potential of potassium be zero if the concentration of potassium is higher on the outside e. None of the abovearrow_forward
- Action potentials and graded potentials both…A) Propagate long distances through neural structures, without attenuation in their amplitude.B) Can directly excite or inhibit neurons.C) Can propagate at speeds of up to 120 meters per second.D) Involve voltage-gated Nav and Kv channels.E) Are capable of triggering synaptic exocytosis in neurons of the vertebrate retinaarrow_forwardSchwann cells are a type of glial cell found in the nervous system. In addition to the conduction of nerve impulses, the outermost layer called neurilemma aids in nerve development and regeneration. After examining the image below, can you explain why brain cells have limited capacity for regeneration? Human Brain Cross Section. Rajalakshmi L Nair et al. Select one: a. Neurons in the central nervous system lack neurilemma of Schwann cells. O b. Neurons in the central nervous system are surrounded by white matter. c. Axons of the peripheral nervous system lack neurilemma of Schwann cells. d. Neurons in the peripheral nervous system are surrounded by grey matter.arrow_forwardWeaver mice have difficulty maintaining posture and moving normally. This defect has been attributed to a defect in some potassium channels that allows Na+ as well as K+ to pass through the channel. Increasing the sodium permeability will have what effect on the membrane potential of the neuron? The membrane potential will become more negative There will be no change in membrane potential There is not enough information to answer this question The membrane potential will become less negativearrow_forward
- What adaptive advantage do synapses provide in nervoussystems (i.e., why isn’t the nervous system just a mesh of cellscytoplasmically connected through gap junctions)?arrow_forwardConotoxin is produced by marine cone snails. Among its effects is to block voltage-gated Ca2+ channels in n eurons. A. What anatomical part of a neuron would be affected by conotoxin? B. How would the neuron's action potential be affected by conotoxin? Explain, using at least TWO of the following terms: threshold, depolarization, repolarization, hyperpolarization, summation, IPSP, EPSP, exocytosis C. If conotoxin affected a somatic motor neuron, would this toxin cause muscle weakness or increased muscle tension? Explain why.arrow_forwardNeurotransmitters, the chemicals used in signaling across synapses, can be either re-absorbed by the pre-synaptic neuron OR hydrolyzed after release by enzymes. Acetylcholine (ACh), the neurotransmitter at neuromuscular junctions, is broken down by the enzyme acetylcholinesterase (AChE) and then its component parts are re-absorbed. Sarin gas is an extremely dangerous neurotoxin that has been utilized in terrorism and chemical warfare. It is known as a "nerve gas" because it blocks AChE. Based on your understanding of the neuromuscular junction and hydrolitic enzymes, hypothesize how sarin gas le ads to paralysis and nerve damage in the people to whom it is exposed.arrow_forward
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