Cardiovascular System Flashcards
(17 cards)
What is the average cardiac output of a person at rest
5 L/min
What is the equation for calculating cardiac output
Heart rate x stroke volume
What is cardiac hypertrophy
Long term structural changes in the size of the left ventricle
What is the equation for constant flow rate
Blood flow velocity x cross sectional area
What do poiseuille’s laws state
- Flow is proportional to the difference between inflow and outflow pressure
- Flow is inversely proportional to length of the vessel
- Flow is proportional to radius of the vessel
- Flow is inversely proportional to the viscosity of the blood
All of the above have different differences in effect size
What is a syncytium
A single multi-nucleated cell formed from many fused cells
Only 99% of cardiac muscle cells are contractile what does the remaining 1% do
They regulate the autonomic rhythm of the heart
What are the 4 events of cardiac excitation
- Atrial depolarisation
- Ventricular depolarisation
- Atrial repolarisation (hidden by the above)
- Ventricle repolarisation
What is systole
Contraction
What is the equation for calculating mean blood pressure
Cardiac output x total peripheral resistance
Useful equations for the cardiovascular system
- Stroke vol = end diastolic volume - end systolic volume
- Cardiac output = stroke v x heart rate
- Pulse pressure = systolic BP - diastolic BP
- Mean BP = diastolic BP + 1/3 of pulse pressure
- Flow = mean BP divided by total peripheral resistance
What are alpha adrenoreceptors responsible for
Contraction of all types of smooth muscle
Where is the sinoatrial node located
In the right atrial wall
Considering action potentials of the sinoatrial node which of the following are false:
1. Depolarisation is caused by efflux of Ca2+
2. Slow depolarisation is caused by sodium/calcium influx and K+ efflux
3. Rapid depolarisation is caused by K+ efflux
4. Sinoatrial node cells do not have a resting potential
1 and 3 are not true
What is phentolamine
A non-selective alpha 1 and alpha 2 adrenoreceptor antagonist
What is furosemide
A loop diuretic
What is the equation to work out systemic mean arterial pressure
MAP = diastolic - 1/3 of systolic - diastolic
