Ex-Physiology, Bioenergetics Flashcards
Name the molecule for all if not most cellular activities
Adenosine Triphosphate
How is ATP synthesized in the Phosphagen system?
Creatinekinase yields phosphate to add to adenosine diphosphate (ADP), resulting in ATP.
What is the length of time for sustained activity of the Phosphagen system?
All out exercise or effort can sustain activity for no more than 30 seconds
What is the Nonoxidative system also known as?
The anaerobic system
Why is oxygen not required in the non-oxidative system?
Only CHO is utilised as energy and produces ATP. The breakdown of CHO results in lactic acid formation, with subsequent muscle fatigue.
What is the length of time for sustained activity of the nonoxidative system?
30 seconds to 3 minutes
What is the Oxidative system also known as?
Aerobic pathway
What is the length of time for sustained activity of the oxidative system?
3 minutes or more
How is ATP synthesised throughout the oxidative system?
With the use of CHO and FAT; resulting in by-product of water and CO2.
Name the three systems by which skeletal muscle is able to produce ATP
- Creatine Phosphate
- Rapid glycolysis, or the nonoxidative/ anaerobic system
- Aerobic oxidation
Oxidation of CHO results in?
via the Krebs cycle and ETC results in a total of 36 ATP p/glucose or 38 p/glycogen
Fats or triglycerides are broken down to?
Broken down to glycerol and fatty acids by hormone-sensitive lipase.
At the onset of muscular work, what systems primarily contribute?
Creatine phosphate and rapid glycolysis.
Name the three common myosin isoforms and their twitch properties.
- I, slow twitch but high oxidative capacity
- IIA, intermediate twitch and oxidative capacity
- IIX or IIB, fast twitch low oxidative
Define minute ventilation (VE).
The volume of air inspired/expired over 1 minute
How much is VE generally at rest?
At rest VE is about 6L/min
The response for the increase in minute ventilation during exercise is due to?
A increase in tidal volume, as well as an increase in respiratory rate.
At rest Stroke Volume is typically?
70 mL
At rest Cardiac Output is typically?
5 L/min
What is the Ejection Fraction range typically for healthy individuals?
50-70%
As exercise intensity increases, what happens to components of the cardiac cycle?
- EDV increases as result of venous return increasing.
- Stroke volume increases as result of EDV increasing.
- Increased contractility increases EF
What are the two common cardiac adaptations to aerobic training?
- Resting HR decreases
2. Resting Q remains unchanged, therefore SV increases to compensate (trained individuals).
How does gravity effect venous return?
- Supine and prone positions cause venous return to be more efficient from the legs.
What effect does supine/prone posture have on the heart?
Causes increased venous return; increased EDV and increased SV. Q is remain unchanged as well as resting HR.
What effect does preload have on SV?
Preload has a positive effect on SV as it relates to wall stress at End Diastole. An increase in EDV results in an increase in SV (Frank Starling).
Define afterload and how it could have a negative effect on SV.
Afterload is LV wall stress during ejection. Increased afterload creates greater resistance to ejection of blood and SV is reduced.
What are the two major modifications the vascular system undergoes during exercise?
- A redistribution of blood flow to meet increased demand of working muscle.
- Overall vasodilation resulting in decreased total peripheral resistance/ systemic vascular resistance.
What are the three main indications for cessation of exercise where cardiovascular response is concerned?
- A sudden drop in systolic pressure
- A significant increase systolic 260 mmHg
- A rise in diastolic pressure >15 mmHg
How is afterload and vascualr compliance related?
- Decreases resistance of blood flow against vessels
- SV is not impaired
- Ventricles have easier contraction
- Decreased risk atherosclerosis
Why is Rate Pressure Product useful?
- Correlates between myocardial O2 uptake and LV workload
2. Provides quantitative values of myocardial stress
What happens to SBP/ DBP at steady-state submaximal workloads?
- It will increase and plateau whereas DBP will remain the same or slightly decrease.
