NPB101-Usrey-Debello-MI

NPB101-Usrey-Debello-MI - "" ~Wl W6 m 78 6 9 V/l...

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Unformatted text preview: "" ~Wl W6 m 78 6' 9' '_ V/l. Which of the following statements best describes homeostasis? v 1 D9 be C3) homeostasis is the dynamic maintenance of a stable internal (extracellular) $1 / environment within the organism. Each cell in the body depends on homeostasis for its own survival. Each organ system contributes to homeostasis by counteracting changes to the stable internal environment. b. homeostasis occurs when the body’s organ systems lose their ability to function and directly leads to the death of the organism. c. homeostasis is the inability of an organ system to counteract change in the internal environment within the organism. d. homeostasis refers to the evolutionary theory that animals are constantly evolving and that the animal kingdom will ultimately evolve into plants and become static. “2. Which intracellular structure’s primary role is for intracellular transport? /a’. mitochondria b. lysosomes microtubules 21.’ chemical synapse e. microtrabecular lattice ‘/3. Which of the following is n‘gta fiinction of membrane proteins? /af they serve as channels. they determine the fluidity of the membrane. they serve as carriers. if they serve as receptor sites er” they serve as membrane—bound enzymes. Osmosis occurs when water diffuses down its concentration gradient. Given that the plasma membrane of cells is permeable to water, what would be the effect of increasing the extracellular concentration of a nonpermeable sugar such as sucrose? cell volume would decrease. b. the rate of oxidative phosphorylation would increase c. the membrane potential would hyperpolarize. d. there would be no effect on the cell. c. the rate of glycolysis would decrease. ‘4 According to F ick's law of diffusion, which of the following changes would decrease—the rate of net diffusion of a substance across a membrane? a/ an increase in the substance's concentration gradient . b: an increase in the permeability of the membrane to the substance }. an increase in the surface area of the membrane f3? an increase in the thickness of the membrane Me. None of these answers. l/6. Which protein(s) is/are responsible for development of the resting membrane potential? leak channels. ._ r" f V gated channels. v pumps. / 3. Both (a) and (b) above. khe. Both (a) and (c) above. t53< he Na+/K+ ATPase is a transmembrane protein that transports Na+ and K+/ions against their concentration gradients. The conformation of the protein and its binding affinities for Na+ and K+ «y are determined by the state of intracellular phosphorylation. Which effect of phosphorylation or dephosphorylation can best account for the active transport of Na+ and K” ions across the PM ? 'L a. phosphorylation exposes the intracellular binding sites of both ions, and increases the binding affinity to Na+ and decreases the binding affinity to K+. /b’.' dephosphorylation exposes the intracellular binding sites of both ions, and decreases the binding affinity to both ions. /c./ phosphorylation exposes the extracellular binding site of NaJr and the intracellular binding site of K+, and decreases the binding affinity to both ions. /d./ dephosphorylation exposes the intracellular binding sites of both ions, and decreases the binding affinity to both ions. ACE? l» l . fine electrical gradient for K+ K ‘9 . favors its movement out of the cell at resting potential. / w t . favors its movement into the cell at resting potential. +3 '7 ' opposes the concentration gradient for K at the equilibrium potential or K. a both (a) and (c) above. a both (b) and (c) above. 9. Which of the following best describes the sequence of events that occurs when a neuron fires an action potential? (at? During the rising phase of the spike, K+ channels are gated open by depolarization and K+ flows into the cell. The resulting depolarization causes the K+ channels to rapidly inactivate, v preventing any further entry of K+ ions into the cell. At the same time, but at a slower rate, Na+ channels are gated open by the depolarization, Na+ flows out of the cell and this causes the membrane potential to repolarize. JV During the rising phase of the spike, NaJr channels inactivate and prevent Na+ from entering the cell. At the same time, K+ channels are gated open by the depolarization, K+ flows into the cell causing the membrane potential to depolarize further. The depolarization causes the K+ channels to inactivate and this process leads to repolarization of the membrane potential. During the rising phase of the spike, Na+ channels are gated open by depolarization and Na+ flows into the cell. The resulting depolarization causes the Na+ channels to rapidly inactivate, preventing any further entry of Na+ into the cell. At the same time, but at a slower rate, K+ channels are gated open by the depolarization, K+ flows out of the cell and this causes the membrane potential to repolarize. / During the rising phase of the spike, Na+ channels are gated open by depolarization and Na+ flows out of the cell. The resulting hyperpolarization causes the Na+ channels to rapidly inactivate, preventing any further flow of Na+ out of the cell. At the same time, but at a slower rate, K+ channels are gated open by the depolarization, K+ flows into the cell and this causes the membrane potential to depolarize. . The relative refractory period of an action potential is the period during which a neuron can generate another action potential, but only if the intensity of the stimulus is greater than normal. Which process is responsible for the relative refractory period of a neuron? g the activation of K+ channels. . the inactivation of NaJr channels. 0. the activation of Na+ channels. d. the inactivation of K+ channels. $444 11. Which disease leads to a condition in which neurons lose their myelin sheaths? , /aT Anorexia Nervosa. .4 A5: Botulism. 0. Multiple Sclerosis. K Tay-Sachs. % Myasthenia Gravis. 12. Action potential propagation occurs in unmyelinated axons because /a./ the Na+ entering the axon at the site of an action potential flows to adjacent regions of the membrane and blocks the opening of KJr channels. /b./ the depolarization of the membrane turns on voltage-gated Ca” channels allowing Ca++ to flow into the cell which activates Na+ channels in adjacent regions of the membrane. 0. a non-local field effect is established that permits quantum mechanical tunneling of electrons to adjacent regions of the membrane. the Na+ entering the axon at the site of an action potential flows to adjacent regions of the membrane causing it to depolarize and reach threshold. 13. Exocytosis of neurotransmitter is triggered by the entry of into the cell. a. KJr b. Na+ @ Ca2+ d. ATP e. A' / . Which process is necessary for the entry of Ca++ into the presynaptic terminal of a chemical synapse? .- inhibition of the presynaptic neuron. depolarization of the presynaptic terminal. &(4 945 e an increase in the extracellular concentration of Ca” near the presynaptic terminal. /d./ binding of the neurotransmitter molecules to the postsynaptic receptors. /e.’ breakdown of the neurotransmitter molecules in the synaptic cleft by enzymatic degradation. 15. Graded potentials a. are local changes in membrane potential that occur in varying degrees of magnitude. b. serve as short~distance signals. c. serve as long-distance signals. @ Both (a) and (b). e. Both (a) and (c). 16. The release of neurotransmitter at an excitatory synapse causes the membrane potential of the postsynaptic neuron to depolarize. Which of the following provides the best explanation for the occurrence of the depolarization. /aa the neurotransmitter binds to the postsynaptic receptors and causes a decrease in ermeability to Cl' ions. . the neurotransmitter binds to gap-junction proteins and enhances the flow of ionic current between cells. ' c. the neurotransmitter binds to the postsynaptic receptors and gates an increase in permeability to Nir ions. d/ the neurotransmitter binds to presynaptic receptors and enhances the further release of neurotransmitter. 17. What is the fate of ACh following binding to receptors? ,a./ it remains bound causing continued excitement. (‘55 it is removed by the enzyme acteylcholinesterase. it is actively reabsorbed the axon terminal. ,dc’ it is passively reabsorbed by the muscle cell. e. None of these answers. Tetanus toxin a combines with glycine receptors, thus blocking the action of this inhibitory a.) neurotransmitter. b. destroys dopamine in the region of the brain involved in controlling complex a. movements. @ prevents the release of the neurotransmitter SALSA (gamma-aminobutyric acid) from presynaptic inputs terminating on neurons that supply skeletal muscles. d. promotes presynaptic facilitation. e. causes retrograde flow in axon. ~- . Which subdivision of the peripheral nervous system uses Acetylchoiine (ACh) as a neurotransmitter? - the post-ganglionic parasympathetic system . the post-ganglionc sympathetic system (c: the somatic motor system d. the central somatosensory system C5 both a and c 20. Inficonvergence, Fa.- thousands of synapses from many different presynaptic celis end upon a single postsynaptic cell. b. the axon of a nerve cell branches so that the activity in one neuron influences many other cells. the dendrites all converge upon the cell body. 0. d. All of these answers. None of these answers. .n 2 l. Sensory receptors Va. respond to various physical or chemical changes in their environment. Vb. change other forms of energy into electrical energy. c. respond more readily to their adequate stimulus. a. are found at the peripheral endings of afferent neurons. All of these answers. 22. laggection of the basilar membrane gag} activates hair cell receptors. ‘ occurs in response to fluid movements in the cochlea. \ . . c. results from displacement of the round WlndOW. (3 Both (a) and (b) above. e. All of these answers. 23. The auditory system differs from the visual or somatosensory system in the following respects: ,a./ there are no maps in the auditory system. b. information about the location of an auditory stimulus is represented directly on the surface of the sensory receptors. there is binaural convergence at an early level of the auditory pathway. :31 both (a) and (c) above. e. both (b) and (0) above. 24. Which of the following is the proper sequence of retinal processing? rods and cones—ganglion cells-bipolar cells. rods and cones-bipolar cells—ganglion cells. ganglion cells-bipolar cells-rods and cones. ganglion cells-rods and cones-bipolar cells. bipolar cells-ganglion cells-rods and cones. 9999‘?” 25. Which of the following Moccur in a photoreceptor during exposure to light? 31“ membrane hyperpolarization. b.” closure of Na+ channels in the outer segment. increased transmitter release from the synaptic terminal. 11. decrease in cyclic GMP in the outer segment. «e. closure of Ca channels in the synaptic terminal. 26. You're a neurologist and a patient comes to see you for help after being involved in a car accident. You conduct a standard neurological examination and find that the patient has mtactilg sensation in his left handz no stretggsormtahdra‘ gal reflexes to stimuli placed on the lefi hand, but can voluntarily move his left hand with no pro em. Which region of the nervous system do you conclude is most likely to have been damaged during the accident? @ one of the left dorsal root ganglia at the level of the cervical spinal cord. 1;. the hand representation of the right primary somatosensory cortex. /d the hand representation of the right primary motor cortex. d. one of the right dorsal root ganglia at the level of the cervical spinal cord. /e./ the hand representation of the left primary somatosensory cortex. 27. During a competitive fencing match your opponent's face guard shifts slightly and you accidently pierce the base of his skull with your saber. He is rushed to the emergency L (1 room and given a magnetic resonance image to determine what part of his brain has been injured. The neurologist finds that the left optic tract has been severed. What form of visual field deficit does he have as a result of the accident? a complete loss of vision in the left visual field of both eyes. {Rib a complete loss of vision in the right visual field of both eyes. We”. a complete loss of vision in the upper visual field of the left eye and the lower visualfi' field of the right eye. d. a complete loss of vision in the left visual field of the left eye and the right visual field of the right eye. e. a complete loss of vision in the right visual field of the left eye and the left visual field of the right eye. 28. Which of the following is not accomplished by the cerebral cortex? f voluntary initiation of movement. ® control of breathing, circulation, and digestion. 127 final sensory perception. '6'." language ability. e. personality traits. 29. During voluntary movement the spinocerebellum a. receives a copy of the motor output pattern generated in motor cortex. b. receives afferent information from the body. c. compares intended and actual movement. (1. adjusts the motor output pattern to correct movement errors. Q all of the above are correct. 30. What part of the brain is crucial for consolidation of short-term memory into long-term memory? hippocampus. . basal nuclei. c. cerebellum. d. cerebral cortex. e. hypothalamus. 31. You have test form D. Please answer D to this question. ...
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NPB101-Usrey-Debello-MI - "" ~Wl W6 m 78 6 9 V/l...

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