Exam # 3 essays

Exam # 3 essays - BIOLOGY 124 - Sample Essay Questions for...

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BIOLOGY 124 - Sample Essay Questions for Exam #3 Name the 3 types of muscle. Compare differences in cell structure, location, function and activation mechanism. Skeletal Muscle- Cylindrical, longest, striations (alternating light/dark bands), Attach to and cover the bony skeleton (one exception: extraocular muscles), Moves bones of skeleton, Rapid contractions, tires easily, adaptable force ranging from a fraction of an ounce to many pounds, Voluntary control (conscious) Cardiac Muscle-Striations, intercalated discs, gap junctions, Heart, Steady rate of contraction to pump blood continuously, Involuntary, Internal pacemaker + other controls to alter rate Smooth Muscle- Spindle-shaped, no striations, gap junctions, Walls of organs (stomach, bladder, respiratory passages, blood vessels, etc.), Maintain internal environment (moves substances through internal body channels), Slow sustained contractions, Involuntary What is the purpose of glycogen and myoglobin in skeletal muscle cells? *Glycogen – stored for energy production Glycogen -> glucose + ATP *Myoglobin- binds oxygen Why does skeletal muscle have such a high blood and nerve supply? Nerve: Must be stimulated before contraction Blood: High metabolic need *ATP required for contraction + relaxation *Nutrients, oxygen, waste + heat removal Draw and label a sarcomere. *Actin-thin *Myosin- thick What structures are included in “triad?” T-tubules + 2 terminal cisterns of SR *Located at A/I band junction *Zipped together via integral proteins (interaction during neural stimulation) Describe the function of the troponin-tropomyosin complex. Regulation of Contraction Describe the role of calcium in muscle contraction. (Explain where it is stored, what causes its release, what happens after it is released, and how does it get put back into storage). Calcium binds to troponin Troponin undergoes a conformational change Tropomyosin moves away from actin’s binding sites
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~Excitation-Contraction Coupling Calcium channels (in axon membrane) open - allows Ca2+ to enter the axon Ca2+ inside the axon terminal causes vesicles of NT to fuse with the axonal membrane
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This note was uploaded on 03/31/2008 for the course BIO 124 taught by Professor Tondi during the Fall '07 term at George Mason.

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Exam # 3 essays - BIOLOGY 124 - Sample Essay Questions for...

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