old exam 1 - 1 1 Which of the following contains blood with...

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1 1.  Which of the following contains blood with the lowest oxygen content? (A) aorta (B) left atrium (C) right ventricle (D) pulmonary veins (E) systemic arterioles 2.  Forces responsible for the movement of Na +  across the cell membrane in a resting cardiac contractile cell  include:  1. electrical 2. osmotic 3. concentration gradient 4. hydrostatic (A) 1 and 3 (B) 2 and 4 (C) 1, 2, and 3 (D) 1, 2, 3, and 4 3.  How does norepinephrine modulate the contractility of the beating heart? 1. increases the open time of the voltage-gated calcium channels 2. increases Ca 2+  stores in the SR by increasing the Ca 2+ -ATPase activity 3. speeds up the Na + /Ca 2+  antiport carrier (transporter) 4. inactivates the calcium-induced calcium channels (ryanodine receptor-         channels) on the SR (A) 1 and 2 (B) 3 and 4 (C) 1, 2, and 3 (D) 1 only 4.  Drug “X” blocks voltage-gated Ca 2+  channels ( i.e. , “X” prevents movement of ions through the channels).  If this drug were placed on cardiac contractile cells, how will it alter the contraction of the cells? (A) The relaxation phase of the contraction would last longer. (B) The force of contraction would greatly diminish. (C) The depolarization phase would be shortened. (D) The duration of the contraction would increase. (E) It would have no effect. 5.  If more I f  channels were open, the slope of the pacemaker potential of the autorhythmic cardiac cells  would: (A) be steeper (toward threshold). (B) be more shallow (toward threshold). (C) become flat. (D) be steeper (in a negative direction away from threshold). 6. Which of the following structures is/are  NOT  involved in transmitting electrical impulses from the AV node  to the heart muscle? (A) AV bundle. (B) Bundle branches.
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2 (C) Purkinje fibers. (D) Internodal fibers. 7.  The depolarization phase of the action potential of a contractile cell in the left atrial wall would coincide  with which part of the ECG? (A) Just before the P wave.
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This note was uploaded on 09/19/2008 for the course BIO 416L taught by Professor Lagowski during the Fall '08 term at University of Texas.

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old exam 1 - 1 1 Which of the following contains blood with...

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