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1) Cardiovascular System
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What are the two primary functions of the cardiovascular system?


1) Supply oxygen and nutrients
2) Remove carbon dioxide and wastes


What are the three required components of the cardiovascular system?


1) Heart
2) Vasculature
3) Regulatory Mechanisms


What are two important properties of the heart that are required for it to pump blood?


1) Volume-Cardiac Output (CO)
2) Pressure-Aterial Pressure (MAP)


What are the two regulatory mechanisms of the heart and what do they do?


1) Local:  each individual organ can regulate its own blood flow to an extent
2) Global:  global control


Where are action potentials generated in the heart and how are they generated?


Pace maker in SA Node through spontaneous depolarization


Does the heart need nerves to contract?


No


What are two special characteristics of action potentials in the heart?


1) Long action potential
2) No summation or tetanus


What are the two specialized conduction systems of the heart and why are they important?


1) Rapid (potential to all fibers)
Need synchronous contration essentially all at once
2) Fibrous tissue between atria and ventricles
AV Node has a delay which keeps atriums and ventricles from contracting at the same time



Is there recruitment of the fibers of the heart?


No, all fibers of the heart are recruited at the same time.


What is the pressure of the systemic circulation?


~120/80 mmHg


What is the pressure of the pulmonary circulation?


~25/8 mmHg


When do atrioventricular valves open and close?


Open-Pressure: Atrium > Ventricle
Close-Pressure: Ventricle > Atrium


When do semilunar valves open and close?


Open-Pressure: Ventricle > Aorta or Pulmonary
Close-Pressure: Aorta (Pulmonary) > Ventricle


What is systole?
Diastole?


Systole:  Contraction
Diastole:  Relaxation


In an ECG what does the following letters stand for:
1) P
2) QRS
3) T


1) Atrial depolarization
2) Ventricular depolarization
3) Ventricular repolarization


What occurs on an ECG during atrial systole?


P-wave (atrial depolarization)


What valves are open/closed during atrial systole?


Open: atrioventricular valves
Closed: semilunar valves


What are the three stages of ventricular systole?


1) Isovolumic contraction
2) Rapid ejection
3) Reduced ejection


What is "isovolumic" contraction?


Ventricle contraction with no corresponding volume change

Synonymous with "isovolumetric" and "isometric"


What occurs on an ECG during isovolumic contraction?


QRS (ventricle depolarization)


What valves are open/closed during isovolumic contraction?


Closed:  atrioventricular valve snaps shut
Closed:  Aortic valve still closed


What causes the first heart sound?


When the atrioventricular valve closes


What is happening to the atrium during an isovolumic contraction?


The atrium is still filling


What valves are open/closed during rapid ejection?


Open:  Semilunar valve
Closed:  Atrioventricular valve


What is the pressure of the aorta during rapid ejection?


120 mmHg


What occurs on an ECG during reduced ejection?


T-wave (ventricle repolarization)


What are the three stages of ventricular diastole?


1) Isovolumic relaxation
2) Rapid ventricular filling
3) Slower ventricular filling


What valves are open/closed during isovolumic relaxation?


Closed:  Semilunar valve closes


When does the 2nd heart beat sound occur?


During isovolumic relaxation


What is a dicrotic notch and when does it occur?


A slight increase in aortic pressure due to the closing of the semilunar valve
Occurs during isovolumic relaxation


Why is it important to have a rapid filling phase?


Diastole will shorten more than systole if heart rate needs to increase


What valves open/close during rapid ventricular filling?


Opened:  Atrioventriular valve opens


What is the equation for "stroke volume?"


Stoke volume = End Diastolic Volume - End Systolic Volume
SV = EDV - ESV


What are two ways to increase stroke volume?


1) Decrease End Systolic Volume
2) Increase End Diastolic Volume


What is the equation for "ejection fraction?"



Ejection Fraction = Stroke Volume/End Diastolic Volume
EF = SV/EDV


What is the equation for "Pressure-Volume Work?"


Pressure-Volume Work = Volume x Developed Pressure

P-V Work = Volume x (Mean Ejection Pressure - End Diastolic Pressure)


What type of metabolism does the heart use?


Aerobic (almost exclusively)


What are the four determinants of myocardial oxygen consumption (MVO2)?


1) Pressure
2) Radius
3) Inotropic State
4) Heart Rate


What are the four determinants of cardiac performance?



1) Preload
2) Afterload
3) Inotropic State
4) Heart Rate


What are the effects of increasing preload of the heart (afterload, contractility constant)?


Increase Stroke Volume
Increase End Diastolic Volume


What limits the effects of increasing preload of the heart?


Pulmonary edema


What effects do increasing the load have on muscle?


Rate of shortening decreases
Extent of shortening decreases


What are the effects of increasing afterload of the heart (preload, contractility constant)?



Decrease Stroke Volume
Increase End Systolic Volume


What are the effects of increasing contractility of the heart (preload, afterload constant)?


Increase Stroke Volume
Decrease End Systolic Volume


What is the equation for "Cardiac Output?"


Cardiac Output = Stroke Volume x Heart Rate
CO = SV x HR