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Unformatted text preview: elf, adjust its length), sensory neurons
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) 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 supplied by: Breakdown of CP
Duration of ATP supply: Short (3-15 s)
ATP supplied by: Anaerobic breakdown of glycogen
Duration of ATP supply: A few minutes at most.
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
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This document was uploaded on 01/28/2014.
- Winter '13