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muscle - kashmala - Printable Version +- USMLE Forum - Largest USMLE Community (https://www.usmleforum.com) +-- Forum: USMLE Forum (https://www.usmleforum.com/forumdisplay.php?fid=1) +--- Forum: Step 1 (https://www.usmleforum.com/forumdisplay.php?fid=2) +--- Thread: muscle - kashmala (/showthread.php?tid=165629) |
muscle - kashmala - ArchivalUser - 02-27-2007 A 23-year-old track runner comes to your office complaining of lower extremity pain. The pain is localized to the right lower hamstrings. The patient sensed the pain immediately after completing a 1-mile sprint. Which of the following statements is true regarding muscle fibers? A Cardiac muscle does not have actin and myosin organized into sarcomers. B Red muscle fibers have a large mass per motor unit. C Skeletal cells have limited sarcoplasmic reticulum. D Smooth muscles have high ATPase activity. E White muscles have a high capacity for anaerobic glycolysis 0 - ArchivalUser - 02-27-2007 e? 0 - ArchivalUser - 02-27-2007 d???? 0 - ArchivalUser - 02-27-2007 eee 0 - ArchivalUser - 02-27-2007 eee 0 - ArchivalUser - 02-27-2007 yes E weldone A Cardiac muscle does not have actin and myosin organized into sarcomers. Cardiac muscle does have sarcomers, and they determine the Frank-Starling mechanism. B Red muscle fibers have a large mass per motor unit. Red muscle fibers have a small mass per motor unit because they typically belong to muscles that do not require less power. C Skeletal cells have limited sarcoplasmic reticulum. These muscle fibers typically have extensive sarcoplasmic reticulum because the calcium needs to bind to troponin to activate the muscle fiber. D Smooth muscles have high ATPase activity. Smooth muscles have low ATPase activity. Cardiac and skeletal muscles have a higher ATPase activity because they are involved in more rigorous work. E White muscles have a high capacity for anaerobic glycolysis. White muscles have a high capacity because they are used as large, powerful muscles in short-term bursts of activity 0 - ArchivalUser - 02-27-2007 EE |