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Unformatted text preview: Stored fat contains more kcal/g than glycogen (so more compact) Stored fat is mobilized more slowly than glycogen (as source of ATP) Figure 22-2 Exercise - start with muscle contraction Skeletal muscle is the largest single tissue type in the human body. >640 muscles 30-40% of total body weight ~25% of energy consumed by body at rest ATP and phosphocreatine (PCr)
Figure 25-1 Exercise - start with muscle contraction Figure 25-1 Speed of ATP production vs endurance Figure 25-2 Your questions
If someone is interested in losing weight, is it better to exercise in the "fat-burning" or the "carbohydrate-burning" level of effort?
Energy in (calories) = Energy out (calories burned) + Energy stored (fat and glycogen) Exercise type affects muscle fiber types ....and capillary density and number of mitochondria (endurance training) Figure 12-15 Lack of exercise affects muscle mass Weight-bearing activities ~1/3 of skeletal muscle in immobilized limb can disappear within weeks Aerobic metabolism uses oxygen Figure 25-5 Homeostatic regulation of arterial oxygen and carbon dioxide levels during exercise Figure 25-6 Cardiovascular response to exercise CO >4x proportion >4x blood (liters/min) to skeletal muscles ~20x cause of proportion shift: vasodilation in skeletal muscles vasoconstriction elsewhere
Figure 25-7 Limitations to athletic performance
• oxygen delivery to muscles by blood • oxygen delivery to blood by lungs • oxygen use by muscle cells • force production by muscle cells ventilation reaches 65% of max. when cardiac output reaches 90% of max (so cardio system sets limit before ventilation system) 1999. Scientific American. How do muscle cells respond to exercise by becoming stronger and thicker?
Transcription of muscle proteins affected by large number of factors (sex hormones, thyroid hormones, growth factors, etc.). Example: anabolic steroids (synthetic version of testosterone) combine with transcription factors to turn on genes and make more muscle proteins. [side effects include high cholesterol levels, changes in hair, atrophy of testicles, hair loss, infertility, aggression, etc.] 2005. American Scientist. from: 2005. Exercise controls gene expression. American Scientist. from: 2005. Exercise controls gene expression. American Scientist. ...
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This note was uploaded on 12/01/2010 for the course BIO SCI Bio Sci E1 taught by Professor Catherineloudin during the Spring '10 term at UC Irvine.
- Spring '10