| 1) Cardiovascular System |
 SlvrDragon |
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| Front | Back | |
What are the two primary functions of the cardiovascular system?
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1) Supply oxygen and nutrients
2) Remove carbon dioxide and wastes
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What are the three required components of the cardiovascular system?
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1) Heart
2) Vasculature
3) Regulatory Mechanisms
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What are two important properties of the heart that are required for it to pump blood?
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1) Volume-Cardiac Output (CO)
2) Pressure-Aterial Pressure (MAP)
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What are the two regulatory mechanisms of the heart and what do they do?
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1) Local: each individual organ can regulate its own blood flow to an extent
2) Global: global control
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Where are action potentials generated in the heart and how are they generated?
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Pace maker in SA Node through spontaneous depolarization
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Does the heart need nerves to contract?
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No
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What are two special characteristics of action potentials in the heart?
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1) Long action potential
2) No summation or tetanus
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What are the two specialized conduction systems of the heart and why are they important?
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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
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Is there recruitment of the fibers of the heart?
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No, all fibers of the heart are recruited at the same time.
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What is the pressure of the systemic circulation?
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~120/80 mmHg
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What is the pressure of the pulmonary circulation?
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~25/8 mmHg
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When do atrioventricular valves open and close?
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Open-Pressure: Atrium > Ventricle
Close-Pressure: Ventricle > Atrium
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When do semilunar valves open and close?
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Open-Pressure: Ventricle > Aorta or Pulmonary
Close-Pressure: Aorta (Pulmonary) > Ventricle
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What is systole?
Diastole?
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Systole: Contraction
Diastole: Relaxation
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In an ECG what does the following letters stand for:
1) P
2) QRS
3) T
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1) Atrial depolarization
2) Ventricular depolarization
3) Ventricular repolarization
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What occurs on an ECG during atrial systole?
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P-wave (atrial depolarization)
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What valves are open/closed during atrial systole?
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Open: atrioventricular valves
Closed: semilunar valves
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What are the three stages of ventricular systole?
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1) Isovolumic contraction
2) Rapid ejection
3) Reduced ejection
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What is "isovolumic" contraction?
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Ventricle contraction with no corresponding volume change
Synonymous with "isovolumetric" and "isometric"
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What occurs on an ECG during isovolumic contraction?
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QRS (ventricle depolarization)
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What valves are open/closed during isovolumic contraction?
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Closed: atrioventricular valve snaps shut
Closed: Aortic valve still closed
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What causes the first heart sound?
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When the atrioventricular valve closes
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What is happening to the atrium during an isovolumic contraction?
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The atrium is still filling
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What valves are open/closed during rapid ejection?
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Open: Semilunar valve
Closed: Atrioventricular valve
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What is the pressure of the aorta during rapid ejection?
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120 mmHg
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What occurs on an ECG during reduced ejection?
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T-wave (ventricle repolarization)
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What are the three stages of ventricular diastole?
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1) Isovolumic relaxation
2) Rapid ventricular filling
3) Slower ventricular filling
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What valves are open/closed during isovolumic relaxation?
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Closed: Semilunar valve closes
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When does the 2nd heart beat sound occur?
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During isovolumic relaxation
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What is a dicrotic notch and when does it occur?
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A slight increase in aortic pressure due to the closing of the semilunar valve
Occurs during isovolumic relaxation
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Why is it important to have a rapid filling phase?
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Diastole will shorten more than systole if heart rate needs to increase
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What valves open/close during rapid ventricular filling?
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Opened: Atrioventriular valve opens
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What is the equation for "stroke volume?"
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Stoke volume = End Diastolic Volume - End Systolic Volume
SV = EDV - ESV
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What are two ways to increase stroke volume?
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1) Decrease End Systolic Volume
2) Increase End Diastolic Volume
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What is the equation for "ejection fraction?"
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Ejection Fraction = Stroke Volume/End Diastolic Volume
EF = SV/EDV
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What is the equation for "Pressure-Volume Work?"
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Pressure-Volume Work = Volume x Developed Pressure
P-V Work = Volume x (Mean Ejection Pressure - End Diastolic Pressure)
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What type of metabolism does the heart use?
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Aerobic (almost exclusively)
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What are the four determinants of myocardial oxygen consumption (MVO2)?
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1) Pressure
2) Radius
3) Inotropic State
4) Heart Rate
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What are the four determinants of cardiac performance?
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1) Preload
2) Afterload
3) Inotropic State
4) Heart Rate
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What are the effects of increasing preload of the heart (afterload, contractility constant)?
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Increase Stroke Volume
Increase End Diastolic Volume
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What limits the effects of increasing preload of the heart?
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Pulmonary edema
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What effects do increasing the load have on muscle?
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Rate of shortening decreases
Extent of shortening decreases
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What are the effects of increasing afterload of the heart (preload, contractility constant)?
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Decrease Stroke Volume
Increase End Systolic Volume
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What are the effects of increasing contractility of the heart (preload, afterload constant)?
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Increase Stroke Volume
Decrease End Systolic Volume
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What is the equation for "Cardiac Output?"
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Cardiac Output = Stroke Volume x Heart Rate
CO = SV x HR
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