Spring07Exam4 - Name KEY Bio416K Physiology and Functional Anatomy I Lecture Exam 4 Spring 07 1 The sarcoplasmic reticulum has the following role

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Name________________________________ KEY - Bio416K Physiology and Functional Anatomy I Lecture Exam 4 Spring 07 1. The sarcoplasmic reticulum has the following role in skeletal muscle contraction: a. Conduction of the action potential stimulated by the end plate potential b. Contains the dihydropyridine receptor proteins that translate the sarcolemma action potential c. Regulates Na + and K + levels in the sarcoplasm to reduce muscle fatigue d. Supplies glycogen and fatty acids for ATP production in the sarcoplasm e. Initiates contraction by releasing calcium in response to the sarcolemma action potential 2. Manganese ions block the calcium channels in the cell membrane of contractile cardiac muscle cells. How would the presence of manganese in the extracellular fluid affect the contraction of the heart muscle? a. The plateau phase of contraction would be longer b. The action potential refractory period would be longer c. The heart would contract less forcefully d. The heart rate would increase e. The contraction phase would be prolonged 3. An important difference between single-unit and multi-unit smooth muscle is: a. Closely controlled individual fibers in singe-unit smooth muscle allow fine control and graded contractions by selective activation b. Longer actin and myosin filaments in multi-unit smooth muscle allow maximum muscle tension even when fiber is stretched c. Numerous gap junctions in single-unit smooth muscle allow many cells to coordinate their activity and contract as a functional unit d. The ability of single-unit fibers to change into multi-unit fibers when advantageous e. All of the above 4. If a skeletal muscle is functioning normally, all of the following will contribute to increased force of muscle contraction EXCEPT : a. Increased frequency of action potentials per somatic motor neuron b. Increased number of motor units recruited c. More actin and myosin protein per fiber (thicker fiber) d. Optimum sarcomere length at the start of contraction e. A greater (larger) end plate potential at the neuromuscular junction 5. What type of lever system is described by the soleus and gastrocnemius muscles as they plantar flex the foot as when standing on your tip toes? a. First class b. Second class c. Third class d. Speed lever 1
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6. Lidocaine is a chemical that blocks the action of voltage-gated Na + channels in cardiac muscle cells. What will happen to the action potential of a contractile cardiac muscle cell if lidocaine is applied to the cell? a.
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This note was uploaded on 04/07/2008 for the course BIO 416K taught by Professor Findell during the Fall '08 term at University of Texas at Austin.

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Spring07Exam4 - Name KEY Bio416K Physiology and Functional Anatomy I Lecture Exam 4 Spring 07 1 The sarcoplasmic reticulum has the following role

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