Excercise Pysiology Flashcards
What is the immediate energy source for exercising muscle
Phosphocreatine
How long does it take for muscles to use up phosphocreatine from start of exercise
10 secs
What is the what catalyses the decomposition of phosphocreatine
Creatine kinase
What pathway is used to generate ATP from glucose anaerobically
Glycolytic pathway
When does the body switch to anaerobic metabolism
In heavy exercise When cells receive insufficient oxygen
Why do muscles fatigue
Drop in pH due to lactate build up
What molecule is converted to lactate in anaerobic metabolism
Excess pyruvate
Is aerobic or anaerobic metabolism more effective at generating ATP
Aerobic
Why does aerobic metabolism require oxygen
For oxidative phosphorylation
What is VO2
Volume of oxygen consumed or the rate of O2 uptake by skeletal muscle
What does the Fick equation calculate
VO2
Does increased fitness raise or lower VO2
Raise
VO2 max
Highest peak O2 uptake that an individual can obtain during dynamic exercise using large muscle groups during a few minutes
What does VO2 show
Aerobic physical fitness
When is VO2 max reached
When O2 consumption remains steady despite increased workload
Anaerobic threshold
Point where lactate begins to accumulate in the bloodstream
What can occur when lactate is produced faster than it can be metabolised
Metabolic acidosis
Does increased fitness raise or lower anaerobic threshold
Raise
How does the cardiovascular system react to exercise
Regional muscle vasodilation
Increase CO by increasing SV and HR
How does the body decrease vascular resistance in exercising muscles
Vasoactive substrates and products of muscle metabolism
Vasoactive mediators released by endothelium
Adrenergic receptor activation
Which vasoactive mediators are released by the endothelium
NO
ATP
Adenosine
Prostaglandins
Which adrenergic receptors cause vasodilation
Beta2
How is CO increased during exercise
Increase HR and SV
How is HR increased during exercise
Incr sympathetic activity
What is SV
Stroke volume
Why does SV start to decrease after initial increase during exercise
Diastolic time decreases when HR increases, so there is less time for the heart to fill
How does the heart remodel in response long term to exercise
Cardiac muscle hypertrophy
Increased resting SV
Compensatory bradycardia
Increased resting EDV
How is MAP calculated
(CO X TPR) + CVP
Why does total peripheral resistance decrease during dynamic exercise
Vasodilation in exercising muscles
How does systolic pressure and MAP change during exercise
Increase
How does pulmonary ventilation increase during exercise
Increase resp rate
Increase tidal volume
Why does venous O2 decrease during exercise
More O2 removed from blood
How does the increased difference between venous and arterial pO2 affect o2 transport
Bigger gradient pushes more O2 to diffuse into tissues
How does Hb binding affinity change during exercise
Decrease
Excess post exercise oxygen consumption
Progressive rise in O2 consumption until it matches demand
What initiates physiological changes due to exercise
Inhibition of parasympathetic and increase in sympathetic impulses due to signals from central command
What part of brain controls changes in exercise
Higher brain levels
What does central command do
Initiate autonomic changes due to exercise
Modulate baroreceptor reflex sensitivity
Receives feedback from increased activity in afferent nerves and exercising limbs
Metaboreceptors respond to changes in metabolite concentrations
What gas is a major driver for ventilation
CO2
What type of receptor is involved in respiratory responses
Central and peripheral chemoreceptors
