Test 3-III - Exam III Fall 2007 Question 1 Your answer is...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Exam III – Fall 2007 Question 1 Your answer is CORRECT. Thick filaments in skeletal muscle are composed of: a) actin b) troponin and tropomyosin c) myosin d) actin, troponin, and tropomyosin e) all of these answers Question 2 Your answer is CORRECT. In an isometric contraction, the muscle: a) changes in length and moves the load b) does not change in length but increases tension c) never converts pyruvate to lactic acid d) rapidly resynthesizes creatine phosphate and ATP Question 3 Your answer is CORRECT. Which of the following statements concerning crossbridges is incorrect? Crossbridges: a) are formed by the globular heads of the myosin molecules as they protrude from the thick filaments. b) bend during muscle contraction. c) bind to actin during muscle contraction. d) bind with troponin and tropomyosin during muscle contraction to pull them away from the actin helical chain. e) None of these Question 4 Your answer is INCORRECT. In twitch summation: a) The muscle fiber is stimulated again before the action potential has returned to resting potential. b) The muscle fiber is stimulated again before the filaments have completely returned to their resting position. c) Stronger muscle contractions occur but stronger action potentials do not occur. d) Both [b] and [c] above e) All of these answers Question 5 Your answer is INCORRECT. Which is not characteristic of smooth muscle? a) it is under involuntary control b) it lacks troponin c) its contraction is initiated neurogenically d) it is found in the walls of hollow tube-like organs e) it is innervated by the ANS
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Question 6 Your answer is CORRECT. Which of the following statements regarding skeletal muscle is true: a) Calcium in muscles cells is required for cross-bridges between actin and myosin. b) ATP binds troponin allowing the myosin-binding site on actin to be made available. c) ATP is stored in the sarcoplasmic reticulum. d) Skeletal muscles lack mitochondria e) All of these Question 7 Your answer is CORRECT. The T tubule travels transversely to the surface of the muscle cell membrane. a) True b) False Question 8 Your answer is CORRECT. Calcium ions are used a second messenger to initiate contraction in a smooth muscle. a) True b) False Question 9 Your answer is INCORRECT. Blood returning from the systemic circulation: a) enters the right atrium. b) enters the left atrium c) is poorly oxygenated. d) both [a] and [c] above e) both [b] and [c] above Question 10 Your answer is CORRECT. The rapid rising phase of the cardiac contractile cells action potential results from the opening of voltage-gated _____ channels in the plasma membrane of the cardiac cell. a) sodium b) potassium c) calcium d) chloride e) magnesium Question 11 Your answer is CORRECT. The QRS complex represents:
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 9

Test 3-III - Exam III Fall 2007 Question 1 Your answer is...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online