SCT III - Muscle Energetics Flashcards
What are the types of muscle?
Speed of Contraction
- Fast
- Slow
Source of Energy
- Oxidative
- Glycolytic
Could be:
1. Fast oxidative
2. Fast glycolytic
3. Slow oxidative
4. Slow glycolytic
What is the classification of slow oxidative skeletal muscles (red)?
Myosin Isoenzyme: Slow
SR Calcium Pumping Capacity: Moderate
Diameter: Moderate
Oxidative capacity: High
Glycolytic capacity: Moderate
Mechanical response: Slow
Basically myosin isoenzyme ^^^
What is the classification of fast glycolytic skeletal muscle (white)?
Myosin Isoenzyme: Fast
SR calcium pumping capacity: High
Diameter: Large
Oxidative capacity: Low
Glycolytic capacity: High
Mechanical response: Fast
What is the classification of fast oxidative skeletal muscle (red)?
Myosin isoenzyme: Fast
SR calcium pumping capacity: High
Diameter: Small
Oxidative capacity: VERY high
Glycolytic capacity: High
Mechanical response: fast
What gives muscle fibers their red color?
Excess of mitochondria
How does the fast oxidative muscle fiber have high oxidative and high glycolytic activity?
High oxidative activity requires metabolites from glycolysis, therefore, it needs to do glycolysis thoroughly before running intense oxidative processes
What is the function of creatine phosphate?
To keep ATP sources constant by:
Creatine-phosphate → Creatine
ADP → ATP via the process
Is glycolysis an aerobic or anaerobic process?
Anaerobic
How is the limit of glycolysis mediated in the body?
Body reaches “anaerobe threshold” where it cannot take anymore lactic acid, and switches to aerobic respiration
What is the optimum load of muscle performance?
1/3 of the maximum force
How long does the creatine phosphate last for during intense exercise?
8-10 seconds
What happens at increased O2 consmption?
Respiratory rate (RR) ↑
Tidal volume (TV) ↑
Maximum stroke volume (SV) ↑
O2 alveolar diffusion ↑
Maximum AV O2 difference ↑
What is the local response to the muscles during physical exercise?
VASODILATION
- Due to sympathetic cholinergic activity
- Due to increased metabolites
- To bring the muscle more blood (nutrients)
What are the changes in systemic circulation that take place during physical exercise?
Heart rate (HR) ↑
Cardiac Output (CO) ↑
Stroke Volume (SV) ↑
Flow of pulmonary circulation ↑
Peripheral resistance (TPR) ↓ - Due to Vasodilation
Redistribution of the circulating blood volume
Summary of circulatory response by the brain to exercise (drawing)