精品课程生理学习题库 Gastrointestinal System Instructions: Select the single best answer to the numbered question. Gastrointestinal Smooth vuscle Question 1 In contrast to the situation in skeletal muscle fibers,the resting membrane potential of aany gastrointestinal smooth musele cells has a large contribution from the electrogenicity of the Na+,K+-ATPase. A.The statement is TRUE. B.The statement is FALSE. Question#2 The smooth muscle cells of the circular muscle of the GI tract are electrically coupled gap junctions between neighboring cells. A.The statement is TRUE. B.The statement is FALSE. Which of the folloring statements is FALSE? A.The resting neabrane potential of GI smooth suscle tends to be smaller in magnitude than that of skeletal muscle. B.Action potentials in GI smooth muscle are not blocked by tetrodotoxin. C.LongitudinalGI smooth mscle cells are less well-coupledelectrically than are circular saooth uscle D.Slow waves are generated by GI smooth muscle cells near the inside of the circular muscle layer. E.Contraction of GI smooth muscle cells may occur in the absence of action potentials. Question #4 Which statement about gastrointestinal smooth muscle is NOT correct? A.The cells of the circular layer of gastrointestinal smooth muscle are coupled by numerous gap junctions. B.The length-tension curve of gastrointestinal smooth muscle is broader than that of skeletal muscle C.In human stomach slow waves occur about 3 times per ninute
精品课程生理学习题库 Gastrointestinal System Instructions: Select the single best answer to the numbered question. Gastrointestinal Smooth Muscle Question # 1 In contrast to the situation in skeletal muscle fibers, the resting membrane potential of many gastrointestinal smooth muscle cells has a large contribution from the electrogenicity of the Na+,K+-ATPase. A. The statement is TRUE. B. The statement is FALSE. -------------------------------------------------------------------------------- Question # 2 The smooth muscle cells of the circular muscle of the GI tract are electrically coupled by numerous gap junctions between neighboring cells. A. The statement is TRUE. B. The statement is FALSE. -------------------------------------------------------------------------------- Question # 3 Which of the following statements is FALSE? A. The resting membrane potential of GI smooth muscle tends to be smaller in magnitude than that of skeletal muscle. B. Action potentials in GI smooth muscle are not blocked by tetrodotoxin. C. Longitudinal GI smooth muscle cells are less well-coupled electrically than are circular smooth muscle cells. D. Slow waves are generated by GI smooth muscle cells near the inside of the circular muscle layer. E. Contraction of GI smooth muscle cells may occur in the absence of action potentials. -------------------------------------------------------------------------------- Question # 4 Which statement about gastrointestinal smooth muscle is NOT correct? A. The cells of the circular layer of gastrointestinal smooth muscle are coupled by numerous gap junctions. B. The length-tension curve of gastrointestinal smooth muscle is broader than that of skeletal muscle C. In human stomach slow waves occur about 3 times per minute
D.Action potentials in gastrointestinal smooth muscle do not involve fast sodium channels. E.None of the above Question#5 Which of the following statements is NOT true? A.Gastrointestinal smooth muscle cells typically have smaller resting membrane potentials than skeletal muscle cells. B.The electrogenic character of the Na,K+-ATPase makes a small contribution to the resting brane ntial of GI oth auscle cells C.Slow waves elicit contraction of some GI smooth muscle even in the absence of action potentials. D.Many GI saooth muscle cells are electrically coupled to their neighbors. E.Action potentials in GI smooth muscle cells do not involve fast sodium channels Question#6 Which of the following statements about the innervation of gastrointestinal sooth musle is NOT true? A.There are no true neuromuscular junctions in gastrointestinal smooth muscle. B.The predominant innervation of the circular muscle layer is inhibitory. C.Most of the nerve fibers that innervate gastrointestinal snooth muscle cells have their cell bodies in the enteric ganglia. D.Most of the nerve fibers that innervate gastrointestinal smooth muscle cells are either cholinergic or adrenergic E.Gastrointestinal smooth muscle is influenced by reflex arcs,all of whose components are located in the gastrointestinal tract. Question#7 Which of the following statements about gastrointestinal smooth mscle is NOT true? A.Its length-tension curve is broader than that of skeletal muscle. B.Cells of the circular layer have numerous gap junctions. C.Contractions are stronger when action potentials occur on the crests of the slow waves. D.Rhythmic oscillations of the resting merbrane potential occur E Tone is due to a baseline level of spontaneous action potentials in the smooth muscle cells. Question#8 Which of the following statements about gastrointestinal smooth muscle is NOT true? A.Slow waves occur at frequencies from3 to 12 per minute.The frequency is characteristic of the various segments of the GI tract. B.Slow waves are generated by interstitial cells.Calcium channels contribute to the depolarizing phas
D. Action potentials in gastrointestinal smooth muscle do not involve fast sodium channels. E. None of the above. -------------------------------------------------------------------------------- Question # 5 Which of the following statements is NOT true? A. Gastrointestinal smooth muscle cells typically have smaller resting membrane potentials than skeletal muscle cells. B. The electrogenic character of the Na+,K+-ATPase makes a small contribution to the resting membrane potential of GI smooth muscle cells. C. Slow waves elicit contraction of some GI smooth muscle even in the absence of action potentials. D. Many GI smooth muscle cells are electrically coupled to their neighbors. E. Action potentials in GI smooth muscle cells do not involve fast sodium channels. -------------------------------------------------------------------------------- Question # 6 Which of the following statements about the innervation of gastrointestinal smooth musle is NOT true? A. There are no true neuromuscular junctions in gastrointestinal smooth muscle. B. The predominant innervation of the circular muscle layer is inhibitory. C. Most of the nerve fibers that innervate gastrointestinal smooth muscle cells have their cell bodies in the enteric ganglia. D. Most of the nerve fibers that innervate gastrointestinal smooth muscle cells are either cholinergic or adrenergic. E. Gastrointestinal smooth muscle is influenced by reflex arcs, all of whose components are located in the gastrointestinal tract. -------------------------------------------------------------------------------- Question # 7 Which of the following statements about gastrointestinal smooth muscle is NOT true? A. Its length-tension curve is broader than that of skeletal muscle. B. Cells of the circular layer have numerous gap junctions. C. Contractions are stronger when action potentials occur on the crests of the slow waves. D. Rhythmic oscillations of the resting membrane potential occur. E. Tone is due to a baseline level of spontaneous action potentials in the smooth muscle cells. -------------------------------------------------------------------------------- Question # 8 Which of the following statements about gastrointestinal smooth muscle is NOT true? A. Slow waves occur at frequencies from 3 to 12 per minute. The frequency is characteristic of the various segments of the GI tract. B. Slow waves are generated by interstitial cells. Calcium channels contribute to the depolarizing phase
of the slow waves C.Circular uscle couped electrically and have numerous kap junctions D.Calcium that enters during an action potential participates in excitation-contraction coupling. E Contractions do not occur in the absence of action potentials. Question 9 Which of the following statements is NoT true? AGI smooth suscle may contract in the absence of action potentials B.Nerves and hormones can influence the frequency and amplitude of slow waves. C.The electrogenicity of the Na,K-ATPase contributes significantly to the resting potential in GI smooth muscle. D.Slow waves are generated in neurons of the myenteric plexus. 1.A2.A3.D4.E5.B6.D7.E8.E9. Gastric Motility Question 1 Gastric smooth scle may contract in response to the depolarizing phase of the slow wave even wher action potentials do not occur at the peak of the. A.The statement is TRU B.The statenent is FALSE Question#2 Indigestible particles that are several millimeters in diameter tend to remain in the stomch betwee meals and are emptied when the following meal stimlates gastric contractions. A The statement is TRUE B.The statenent is FALSE Question #3 Gastric contractions begin in mid-body and appear to travel toward the pylorus,growing in strength as they travel A The stateaent is TRUE. B.The statement is FALSE
of the slow waves. C. Circular muscle cells are well coupled electrically and have numerous gap junctions. D. Calcium that enters during an action potential participates in excitation-contraction coupling. E. Contractions do not occur in the absence of action potentials. -------------------------------------------------------------------------------- Question # 9 Which of the following statements is NOT true? A. GI smooth muscle may contract in the absence of action potentials. B. Nerves and hormones can influence the frequency and amplitude of slow waves. C. The electrogenicity of the Na,K-ATPase contributes significantly to the resting potential in GI smooth muscle. D. Slow waves are generated in neurons of the myenteric plexus. --------------------------------------------------------------------------------- Answer： 1.A 2.A 3.D 4.E 5.B 6.D 7.E 8.E 9.D Gastric Motility Question # 1 Gastric smooth muscle may contract in response to the depolarizing phase of the slow wave even when action potentials do not occur at the peak of the slow wave. A. The statement is TRUE. B. The statement is FALSE. -------------------------------------------------------------------------------- Question # 2 Indigestible particles that are several millimeters in diameter tend to remain in the stomach between meals and are emptied when the following meal stimulates gastric contractions. A. The statement is TRUE. B. The statement is FALSE. -------------------------------------------------------------------------------- Question # 3 Gastric contractions begin in mid-body and appear to travel toward the pylorus, growing in strength as they travel. A. The statement is TRUE. B. The statement is FALSE. --------------------------------------------------------------------------------
Question #4 The presence of acid.fats.peptides.and hypertonicity are sensed by the duodenal mucosa and elicit responses that regulate gastric emptying.Se of these horones increase the rate of gastric emptying.others decrease the rate of gastric emptying. A.The statement is TRUE. B.The statement is FALSE. Question #5 Action potentials on the crests of slowaves in the stomch are not required for contraction of gastri smooth muscle,but when action potentials do occur,the force of contraction is much greater. A.The statenent is TRUE. B.The statement is FALSE. Question#6 which of the following stateents is FALSE? Contractions of the gastric fundus are absent or very weak B.In a fed individual,the pyloric sphincter opens only briefly in response to each peristaltic wave C.Peristaltic waves begin in mid-body and travel toward the pylorus. D.Gastrin enhances the force of gastric contractions. E During gastric contractions that occur during fasting,the pylorus does notopen as ide as it doe during contractions that occur in a fed individual Question#7 An indigestible object about5m in diameter is likely to be enptied froa the stomach into the duodenu B.The statement is FALSE Question#8 Which of the following statements is FALSE? A.Distention of the duodenum evokes neural reflexes that decrease the rate of gastric emtying. in the e release of CCK and GIF C.Gastrin released froa the duodenum enhances both antral contractions and the constriction of the pyloric sphincter. D.Secretin enhances the strength of antral contractions. E Hypertonicity in the duodenum results in decreased rates of gastric emptying
Question # 4 The presence of acid, fats, peptides, and hypertonicity are sensed by the duodenal mucosa and elicit hormonal responses that regulate gastric emptying. Some of these hormones increase the rate of gastric emptying, others decrease the rate of gastric emptying. A. The statement is TRUE. B. The statement is FALSE. -------------------------------------------------------------------------------- Question # 5 Action potentials on the crests of slow waves in the stomach are not required for contraction of gastric smooth muscle, but when action potentials do occur, the force of contraction is much greater. A. The statement is TRUE. B. The statement is FALSE. -------------------------------------------------------------------------------- Question # 6 Which of the following statements is FALSE? A. Contractions of the gastric fundus are absent or very weak. B. In a fed individual, the pyloric sphincter opens only briefly in response to each peristaltic wave. C. Peristaltic waves begin in mid-body and travel toward the pylorus. D. Gastrin enhances the force of gastric contractions. E. During gastric contractions that occur during fasting, the pylorus does not open as wide as it does during contractions that occur in a fed individual. -------------------------------------------------------------------------------- Question # 7 An indigestible object about 5 mm in diameter is likely to be emptied from the stomach into the duodenum by contractions during the gastric phase. A. The statement is TRUE. B. The statement is FALSE. -------------------------------------------------------------------------------- Question # 8 Which of the following statements is FALSE? A. Distention of the duodenum evokes neural reflexes that decrease the rate of gastric emptying. B. Fats in the duodenum elicit the release of CCK and GIP. C. Gastrin released from the duodenum enhances both antral contractions and the constriction of the pyloric sphincter. D. Secretin enhances the strength of antral contractions. E. Hypertonicity in the duodenum results in decreased rates of gastric emptying
Question#9 Which statement about gastric motility is NOT correct? A.The gastric slow wave resembles the cardiac action potential in shape. B.Weak contractions of the fundus and body of the storach subserve the reservoir function of the stomach. c Liquids are emptied a good deal more rapidly from the stonach than digestible solids. D.Larger indigestible ob iects.that remain in the stomach during emptving of a neal.are often emptied during the active contractile phase of the migrating myoolectric complex. E.None of the above. Question#10 Which statement about gastric motility is NOT correct? A.When action potential spikes occur.they result in ipcreased contractile force. BA wave of contraction begins in md-body and moves toward the pylorus,gaining in contractilestrength as it moves C.The pylorus is constricted for a longer time than it is relaxed. D.Secretin,a hormone released by the duodenum,acts to increase the rate of gastric emptying. E.None of the above. Question #11 Which of the following statements is NOT true? A.The fundus and body relax in response to being filled.This is called receptive relaxation. B.Peristaltic contractions of the stomach begin in the middle of the body and travel toward the pylorus. gaining in strength as they travel. C.The force of contraction of gastric smooth mscle is independent of the presence of action potentials on top of the slow waves. D.Indigestible objects in the stomach are likely to be emptied during the migrating myoelectric complex. E.When gastric smooth muscle is depolarized,the theshold for contraction is reached before the threshold for firing action potentials. Question#12 Which of the following statements is NOT true? A.Just after a meal,gastric contractions occur at the frequency of gastric slow waves,about 3 per minute. B.CCK and gastrin enhance the force of gastric contractions and increase the tone of the pyloric C.During the contractions of the migrating myoelectric complex in the stomach the pyloric sphincter
-------------------------------------------------------------------------------- Question # 9 Which statement about gastric motility is NOT correct? A. The gastric slow wave resembles the cardiac action potential in shape. B. Weak contractions of the fundus and body of the stomach subserve the reservoir function of the stomach. C. Liquids are emptied a good deal more rapidly from the stomach than digestible solids. D. Larger indigestible objects, that remain in the stomach during emptying of a meal, are often emptied during the active contractile phase of the migrating myoelectric complex. E. None of the above. -------------------------------------------------------------------------------- Question # 10 Which statement about gastric motility is NOT correct? A. When action potential spikes occur, they result in increased contractile force. B. A wave of contraction begins in mid-body and moves toward the pylorus, gaining in contractile strength as it moves. C. The pylorus is constricted for a longer time than it is relaxed. D. Secretin, a hormone released by the duodenum, acts to increase the rate of gastric emptying. E. None of the above. -------------------------------------------------------------------------------- Question # 11 Which of the following statements is NOT true? A. The fundus and body relax in response to being filled. This is called receptive relaxation. B. Peristaltic contractions of the stomach begin in the middle of the body and travel toward the pylorus, gaining in strength as they travel. C. The force of contraction of gastric smooth muscle is independent of the presence of action potentials on top of the slow waves. D. Indigestible objects in the stomach are likely to be emptied during the migrating myoelectric complex. E. When gastric smooth muscle is depolarized, the theshold for contraction is reached before the threshold for firing action potentials. -------------------------------------------------------------------------------- Question # 12 Which of the following statements is NOT true? A. Just after a meal, gastric contractions occur at the frequency of gastric slow waves, about 3 per minute. B. CCK and gastrin enhance the force of gastric contractions and increase the tone of the pyloric sphincter. C. During the contractions of the migrating myoelectric complex in the stomach the pyloric sphincter