Anatomy and Physiology Answer Key

B intrafusal fibers parallel to extrafusal fibers

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Unformatted text preview: elf, adjust its length), sensory neurons are stimulated. Motor neuron synapses: When the motor impulses arrive to adjust state of contraction, both the extrafusal and intrafusal fibers are adjusted appropriately. The Mechanics of Movement (page 60) 1. Muscles can only contract and relax, therefore they can only pull on a bone; they cannot push it. To produce movement, two muscles must act as antagonistic pairs to move a bone to and from different positions. To raise a limb, the flexor contracts pulling the limb bone up (extensor relaxed). To lower the limb, the extensor contracts, pulling the limb down (flexor relaxed). 2. (a) Radius (b) Ulna (b) Rotation of ulna and radius Energy for Muscle Contraction (page 61) 1. 2. Lactic acid quickly builds up as a waste product of the glycolytic pathway. Lactic acid inhibits glycogen breakdown and impedes muscular contraction, so the time period for its use is limited. Energy systems: ATP-CP ATP supplied by: Breakdown of CP Duration of ATP supply: Short (3-15 s) Glycolytic ATP supplied by: Anaerobic breakdown of glycogen Duration of ATP supply: A few minutes at most. Oxidative ATP supplied by: Complete aerobic (oxidative) breakdown of glycogen to CO2 and water. Duration of ATP supply: Prolonged but dependent on ability to supply oxygen to the muscles (fitness). Muscle Fatigue (page 64) 1. Lactic acid accumulation in muscle tissue results in lowered pH and inhibition of cellular activity. 2. (a) Fall in ATP production (b) Fall in calcium release 3. In a long distance race, such as a marathon, ATP continues to be produced aerobically until all energy supplies are exhausted. In a sprint ATP is produced anaerobically until the oxygen debt has been repaid. Muscle Physiology and Performance (page 65) 1. (a)-(c) Any three, in any order. Endurance training improves the oxidative function of muscle through: – Improved oxidation of glycogen, which increases Biozone International 2009 Photocopying Prohibited 11 – – – – – – 2. the capacity of the muscle to generate ATP aerob...
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This document was uploaded on 01/28/2014.

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