Cardiovascular System and Response to Exercise Flashcards
End Diastolic Volume
Amount of blood in ventricle at end of ventricular filling
As EDV goes up, better ventricular performance
End Systolic Volume
Amount of blood left in ventricles after systole
Preload
Amount of blood coming into/getting back to heart
Increased in supine
Afterload
What pressure ventricle senses when it contracts
Increased with HTN
Contractility
Extent of squeeze
Increases with activity
Frank-Starling Mechanism
More blood in ventricles cause greater stretch
Contract with increased force
Metabolic-CV-Ventilatory Coupling
- PA causes increase in O2 demand/CO2 production at cellular level
- Peripheral circulation dilates
- CV system increases SV and HR
- Pulmonary system recruited to increase tidal volume and breathing frequency
Cardiac Cycle
Events between 2 heart beats/systole to systole/R wave to R wave
Lasts .9 seconds with HR of 67 bpm
Diastole
Relaxation
Low pressure
Ventricles fill with blood
T to QRS
Systole
Contraction or “squeeze”
Ventricles expel blood
QRS to T
Diastole Function
Ventricular filling
Rapid filling due to pressure difference
Final filling - atrial contraction
Systole Function
Isovolumetric contraction - all valves close and close ventricle begins to contract
Ejection phase - outlet valves open
Isovolumetric relaxation - all valves close and pressure falls rapidly
Parasympathetic NS
Vagus
SA Node - causes depolarization
In control at rest
Light to moderate PA
Sympathetic NS
Epinephrine and Norepinephrine - increased myocardial contractility and blood flow
Near max and max effort
Cardiac Regulation
Done by SA node
AV can pace, but slower than SA
AV passes information to bundle of HIS and Purkinje fibers
Maximal Oxygen Consumption
Measure of CRF
VO2 Max = SV*HR (Q) * arteriovenous oxygen difference
AVO2 Difference
How much oxygen is in arterial system versus how much is left in venous system
Cardiac Output
Amount of blood pumped out of heart per unit of time
Stroke Volume
Amount of blood pumped by left ventricle with one contraction
EDV-ESV
Increases curvilinearly with work rate until it reach near max (about 50% of aerobic capacity)
HR (resting)
Averages 60-80 bpm
Range from 30 bpm to 100 bpm
Can decrease with age (abnormal) but likely to increase due to decreased parasympathetic control
Affected by environmental conditions
HR (max)
HR achieved by all-out effort
220-age
HR (steady state)
Plateau reaching during constant rate of submit work
Lower steady-state, more efficient the heart
HR and Intensity
Increase linearly
HR and Training
HR goes down with training due to maximizing stroke volume
HR during Submax loads
HR decreases proportionately with amount of training complete
HR during Max effort
Remanges unchanged or decreases slightly
Decrease may allow optimal stroke volume
