Lecture 29 Flashcards
What are some physiological changes that must occur during aerobic exercise?
- Rate of aerobic ATP synthesis in skeletal muscles must increase (O2 delivery to skeletal muscle mitochondria must increase)
- Alveolar ventilation rate increase
- Tidal volume increase
- Airway resistance decreases
-Cardiac output increase
-TPR decreases - Delivery of fuel sources for aerobic respiration (ex: glucose, fatty acids) to skeletal muscles mitochondria must increase
- Catabolism of energy storage (shifts to post absorptive state)
SKELETAL GLUCOSE MUST REMAIN HIGH DESPITE FALLING INSULIN LVLS - Body temperature homeostasis must be maintained (sweating and peripheral vasodilation.
Why is the simple model of metabolic demands of aerobic exercise inaccurate?
The model assumes that we are not exercising so intensely.
-Aerobic metabolism does not immediately increase/decrease to meet demands of starting/stopping exercise
What happens if you get up and start to exercise right away?
Cells don’t have an ATP reservoir, so your cells would need to make ATP right away.
What happens after you stop exercising?
Cells continue to use more O2- EPOC excess post-exercise oxygen consumption
What helps generate the initial bursts of exercise?
Powered by fast, low efficiency systems: phosphagens, then aerobic glycolysis
What are the three ways our cells generate ATP
- Phosphagen system
- Glycolysis
- Aerobic system
Describe how ATP generation occurs when you exercise
1.) Initial ATP is generated from phosphagens
2.) Then while ATP is being used, glycolysis occurs
3.) While ATP is being generated by phosphagens and glycolysis, aerobic systems (aerobic atp generation) occurs
What happens after you reach your aerobic capacity when exercising?
You must employ anaerobic metabolism to make up the difference in ATP synthesis rate.
- Fatigue much more quickly under these conditions.
What are some possible neuroendocrine mechanisms that regulate ventilation rate during exercise?
Feedback mechanisms
- Increase in temperature leads to increase in respiratory rate
- Chemoreceptors detect blood gas changes (ph decreases, co2 increase, ventilate more)
- Conditioned response (ex: I am exercising, so i will need to ventilate more.)
Feedforward mechanisms:
- Motor cortex: Generates commands to move muscles which can help increase ventilation rate
When you exercise, what is the redistribution of systemic cardiac output?
- Skeletal muscle will receive most of the blood flow from the left ventricle of your heart
- Skin also gets more blood flow
- Brain is getting roughly around the same
- Digestive system gets less blood flow
Describe what happens to the baroreceptors when exercising
Baroreceptors are reset to tolerate a higher blood pressure
- don’t fire so fast..
(normally they reduce cardiac output when blood pressure goes up)
What are cardiovascular changes after initiating exercise?
- Increase in CO
-TPR decreases (vasodilation instead to help blood flow quicker) - MAP increases
- HR increases
-SV increases
What happens to the venous reserve during exercise?
Venous reserve gets utilized
- the more we exercise, the lower the oxygen content gets
During exercise, how does Bohr and temperature effects oxygen delivery?
Bohr and temperature effects will decrease Hb-O2 affinity in the muscles, so it can deliver more oxygen to the blood
What are the endocrine responses to sustained exercise?
- Glucose levels decrease
- Glucagon levels increase (chatgpt-Glucagon promotes the breakdown of glycogen stored in the liver into glucose, which is then released into the bloodstream to provide a steady supply of energy to cells throughout the body.)
- Insulin levels decrease
