Review Flashcards
Sympathetic nerve activity
Increase HR
Increase SV
Increase CO
Increase flow for venous return
Constrict arterioles (decrease conductance)
Parasympathetic nerve activity
Decrease HR
Metaboreceptors
Sense changes in metabolites (H+ and Pi)
If metabolites increase, it increases
Activate the medulla
Feedback control
Metaboreceptors
Baroreceptors
Feedforward control
Mechanoreceptors
Motor outflow/drive
(both activate medulla)
Baroreceptor
Sense changes in MAP
Increase with increasing blood pressure
Inhibit the medulla
Medulla
Activates SNA
Inhibits PSNA
What happens to arterioles with increasing intensity?
Dilation
Blood flow and metabolism
Blood flow increases in proportion to metabolism
Theory 1: The vasodilator hypothesis
As metabolism increases so do the bi-products (vasodilators) such as extracellular K+, adenosine, CO2, Lactate and H+
These cause vasodilation which cause increased blood flow
Theory 2: O2/nutrient lack theory
Decreased O2 availability causes there to be less ATP in the arterioles and therefore smooth muscle relaxation occurs
This causes increased dilation and conductance = Increased blood flow
Ways to increase VO2 max
- Increase blood flow, increase CO, increase DO2
- Increase O2 extraction by increasing CaO2
- Increase capillary density
The impact of hypoxia on a-vO2 difference
Decreases due to decreased CaO2
Ventilation
Increases PaO2
Inhibits PaCO2
PaO2
Inhibits peripheral chemoreceptors
PaCO2
Activates peripheral chemorecptors
H+
Directly activates both peripheral and central chemoreceptors
Feedback control of ventilation
Peripheral chemoreceptors and central chemoreceptors
Feedforward control of ventilation
Mechanoreceptors and motor outflow
Activate the respiratory control centre
Triggers ventilation
Key characteristics of substrate use during exercise
- Increasing intensity increases carbohydrate metabolism
- Increasing duration increases fatty acid metabolism
- Training increases fatty acid metabolism at a given intensity
Increased intensity and increased carbohydrate metabolism
Increased intensity increases ADP
ADP activates glycolysis which triggers the PDH reaction to provide acetylCoA for the TCA cycle
Carbohydrate metabolism
The PDH reaction produces CO2 (pyruvate to acetyl CoA)
High maximal power
If this increases RER increases
Increased duration and training and increased fatty acid metabolism
Fat metabolism creates Acetyl CoA via beta oxidation which can enter the Krebs cycle
Increases aerobic ATP production and decreases outflow from ADP
Less ADP= less activation of glycolysis
Less reliance on carbohydrate metabolism
Fatty acid metabolism
Low maximal power
Creation of acetyl CoA vis beta oxidation
Respiratory exchange ratio
VCO2/VO2
Carbohydrate metabolism increases the ratio
Fatty acid metabolism decreases the ratio
What is RER?
Ratio between the volume of CO2 being produced by the body and the amount of O2 being consumed
Purpose of RER?
Gives us an indication as to whether the body is operating aerobically or anaerobically
