09 practice

09 practice - Lesson 9 Practice Set Cardiac...

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Lesson 9 Practice Set Cardiac Electrophysiology, Cardiac Cycle, and Control of Cardiac Output Part 1. Cardiac Electrophysiology 1. Number the following to indicate the normal order of depolarization in the heart. ____ ventricular myocytes ____ atrial myocytes ____ sinoatrial nodal cells ____ atrioventricular nodal cells ____ common bundle of His ____ bundle branches ____ Purkinje fibers 2. Below is an intracellular recording of the transmembrane potential of a single cardiac cell as a function of time. a. Is this recording from an atrial muscle cell, a ventricular muscle cell, or a pacemaker cell? For the following questions, choose one or more of the letters in the figure above. If none of them are correct answers, write “ none .” b. The resting membrane potential of the cell is labeled _____. c. Fast voltage-gated Na + channels open here: _____. d. Fast voltage-gate Na + channels close here: _____. e. Non-selective cation channels permeable mainly to Na + are open during _______. f. T-type calcium channels are open here: ________. g. The maximum diastolic polarization is labeled _______. 0.1 sec -100 0 Membrane potential mV threshold A A B C D E G B
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h. Activation (opening) of voltage-gated L-type Ca ++ channels is responsible for the depolarization in ________ and the duration of the plateau in ______. 3. Below is an intracellular recording of the transmembrane potential of a single cardiac cell as a function of time. a. Is this recording from a cardiac muscle cell or a pacemaker cell? For the following questions, choose one or more of the letters in the figure above. If none of them are correct answers, write “ none .” b.The resting membrane potential of the cell is labeled _____. c.During ________, [Ca ++ ] in the interstitial fluid is greater than the [Ca ++ ] in the cytosol. d. During ________, [Na + ] in the interstitial fluid is greater than the [Na + ] in the cytosol. e. During ________, [K + ] in the interstitial fluid is less than the [K + ] in the cytosol. f. Fast voltage-gated Na + channels open here: _______. g. Fast voltage-gate Na + channels inactivate here: _______. h. T-type calcium channels are open here: ________. i. Voltage-gated L-type Ca ++ channels open at about _____ and inactivate at about ____. j. A drug that binds to fast voltage-gated sodium channels and prevents or slows down their activation would primarily affect the slope of __________. A B C D E A
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200 msec Membrane potential mV 4 0 1 2 3 4 -100 0 4: Resting membrane potential 0: Rapid depolarization 1: Partial repolarization 2: Plateau 3: Rapid repolarization 4. The figure below illustrates a cardiac ventricular action potential. Different phases of cardiac action potentials are given numbers and the names for these phases are shown below the figure. Below is a review
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09 practice - Lesson 9 Practice Set Cardiac...

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