Module 5 Flashcards
Cardiac Output
amount of blood pumped by heart (5L/min)
Stroke Volume
amount of blood ejected from left ventricle
occurs during ventricular systole
SV Equation
think about systole/diastole
SV = EDV - ESV
how much blood when full - how much blood after contraction
EDV
what is it also effected by
End Diastolic Volume (total amount of blood filling LV)
affected by
- filling time (slower HR = longer filling time)
- fillimg amount (venous return)
ESV
what is it also affected by
amount of blood left following contraction
affected by
- ventricular preload, contractibility and afterload
What is ESV preload and afterload?
Preload = how much fills ventricles (EDV)
Afterload = pressure the ventricle has to overcome to eject (BP)
Frank Starling Curve
relationship between stroke volume and preload/stretch of ventricles/EDV
Cardiac Output
increases to match need for increased O2 to supply working muscles
AKA ‘Q’
Cardiac Output for resting, sedentary max and athlete max
- 5-6L/min
- 20-22L/min
- 35-40L/min
Q Equation
Q = HR x SV
Why does athletes have lower resting HR
myocardium enriched with blood by coronary arteries
- compensate for better ability to perfuse myocardium + heart tissue gets bigger
Sympathetic Nerves
stimulate SA node = tachycardia (noadrenaline)
- increase firing rate/HR
Parasympathetic Nerves
- bradycardia (acetylcholine)
- decreases HR
What happens if HR is too fast
Why its lower in athletes
cannot feed myocardium leading to chest pain associated with heart attack due to insufficient blood supply to heart
oh no! dont let athlete die mudda bullshit
Mechanisms proposed to increase SV during exercise
- increased blood back to heart (venous return) (increased ventricular filling)
- normal ventricular filling followed by forceful contraction
- Training adaptations (increased BV/plasma)
How does exercise affect SV
eFfEctS
- positive inotropic effect (increased contractility)
- negative inotropic effect (decreased contractility)
Preload and Afterload
Preload = atria to ventricle
Afterload = pressure to overload when pushing blood out (ventricle to aorta to body)
LV Volume and Pressure Overload
eccentric hypertrophy (dilation of cavity) e.g. endurance
concentric hypertrophy (walls thicken) e.g. resistance
Heat effect on prolonged exercise
- SV decreases
- HR increases
Cardiovascular Drift
redirection of BF to skin to dissipate for thermoregulation and sweating where plasma volume decreases
decreased VR, EDV/SV leading to increased HR
